Suunto Scuba Diving Equipment HELO2 User Manual

EN  
HelO2  
USER’S GUIDE  
 
1.1. Using HelO2 with Dive Manager and Dive Planner ................................. 5  
2. WARNINGS, CAUTIONS, AND NOTES ................................................... 6  
3. SUUNTO HelO2 AT A GLANCE ............................................................ 9  
3.1. Navigating in the menus ............................................................... 9  
3.2. Button symbols and functions ......................................................... 9  
4. GETTING STARTED WITH YOUR SUUNTO HelO2 ................................... 11  
4.1. TIME mode settings ................................................................... 11  
4.1.1. Setting the time .................................................................. 11  
4.1.2. Setting the date .................................................................. 11  
4.1.3. Setting the units .................................................................. 11  
4.1.4. Setting the backlight ............................................................. 12  
4.1.5. Setting the tones ................................................................. 12  
4.2. AC water contacts ..................................................................... 12  
5. BEFORE DIVING ........................................................................... 13  
5.1. Planning your dives ................................................................... 13  
5.2. The Suunto Technical RGBM ........................................................ 13  
5.3. Emergency ascents ................................................................... 14  
5.4. Dive computer limitations ............................................................. 14  
5.5. Mixed gas diving ....................................................................... 14  
5.6. Audible and visual alarms ............................................................ 15  
5.7. Error conditions ........................................................................ 16  
5.8. Wireless transmission ................................................................. 17  
5.8.1. Installing the wireless transmitter .............................................. 17  
5.8.2. Pairing and code selection ...................................................... 17  
5.8.3. Transmitting data ................................................................ 18  
5.9. MIXED GAS DIVE mode settings ................................................... 19  
5.9.1. Setting the gases ................................................................ 19  
5.9.2. Setting the depth alarm ......................................................... 20  
5.9.3. Setting the dive-time alarm ..................................................... 20  
5.9.4. Setting the personal/altitude adjustments ..................................... 20  
5.9.5. Setting the sample rate .......................................................... 21  
5.9.6. Setting the tank pressure alarm ................................................ 21  
5.9.7. Setting the tank pressure ....................................................... 21  
5.9.8. Setting the HP code ............................................................. 21  
5.9.9. Setting the units .................................................................. 22  
5.10. Activation and pre-checks .......................................................... 22  
5.10.1. Accessing DIVE mode ......................................................... 22  
5.10.2. DIVE mode activation .......................................................... 22  
5.10.3. Battery power indication ....................................................... 23  
5.10.4. Diving at altitude ................................................................ 23  
5.10.5. Personal adjustments .......................................................... 24  
5.11. Safety Stops .......................................................................... 25  
5.11.1. Recommended Safety Stops .................................................. 25  
5.11.2. Mandatory Safety Stops ....................................................... 25  
5.12. Deep stops ............................................................................ 26  
6. DIVING ....................................................................................... 27  
6.1. Diving-related information ............................................................ 27  
6.1.1. Basic dive data ................................................................... 27  
6.1.2. Bookmark ......................................................................... 28  
6.1.3. Ascent rate indicator ............................................................. 28  
6.1.4. Safety Stops ...................................................................... 28  
3
 
6.1.5. Decompression dives ........................................................... 28  
6.2. Diving in MIXED GAS mode ......................................................... 31  
6.2.1. Before diving in MIXED GAS mode ............................................ 31  
6.2.2. Oxygen and helium displays .................................................... 31  
6.2.3. Oxygen limit fraction (OLF) ..................................................... 32  
6.3. Diving in GAUGE mode .............................................................. 33  
7. AFTER DIVING ............................................................................. 34  
7.1. Surface interval ........................................................................ 34  
7.2. Dive numbering ........................................................................ 34  
7.3. Repetitive dive planning .............................................................. 35  
7.4. Flying after diving ...................................................................... 35  
7.5. PLAN mode ............................................................................ 35  
7.5.1. Dive Planning mode (PLANnodec) ............................................ 35  
7.6. MEMORY mode ....................................................................... 36  
7.6.1. Dive logbook (MEMLogbook) ................................................... 37  
7.6.2. Dive history ...................................................................... 38  
7.7. Suunto Dive Planner (SDP) .......................................................... 38  
7.8. Suunto Dive Manager (SDM) ........................................................ 39  
www.suunto.com/diving .................................................................... 39  
9. BATTERY REPLACEMENT ............................................................... 43  
9.1. Battery kit ............................................................................... 43  
9.2. Required tools ......................................................................... 43  
9.3. Replacing the battery ................................................................. 43  
9.4. Wireless transmitter battery replacement ........................................... 44  
9.4.1. Transmitter battery kit ........................................................... 45  
9.4.2. Required tools .................................................................... 45  
9.4.3. Replacing the transmitter battery .............................................. 45  
10. TECHNICAL DATA ........................................................................ 47  
10.1. Technical specifications ............................................................. 47  
10.2. RGBM ................................................................................. 48  
10.2.3. Altitude diving ................................................................... 50  
10.3. Oxygen exposure ................................................................... 50  
11. INTELLECTUAL PROPERTY ............................................................ 51  
11.1. Copyright .............................................................................. 51  
11.2. Trademark ............................................................................ 51  
11.3. Patent notice .......................................................................... 51  
12. DISCLAIMERS ............................................................................ 52  
12.1. User’s responsibility ................................................................. 52  
12.2. CE ..................................................................................... 52  
SUUNTO DIVING COMPUTER ACCESSORIES .......................................... 53  
14. DISPOSAL OF THE DEVICE ............................................................ 56  
GLOSSARY .................................................................................... 57  
4
 
1. WELCOME TO THE WORLD OF SUUNTO DIVING INSTRUMENTS  
Suunto HelO2 was designed to help you get the most out of your diving.  
With easy-to-use PC dive planner and gas switching, Suunto HelO2 simplifies your diving  
experience because all the information you need relating to depth, time, tank pressure,  
and decompression status is available on one easy-to-read screen.  
To get the most out of your Suunto HelO2, please read this instruction manual carefully  
and make sure you understand the use, displays, and limitations of the instrument before  
using it. To make life easier, we've included a glossary of dive-specific terminology at the  
back of the manual.  
1.1. Using HelO2 with Dive Manager and Dive Planner  
Suunto HelO2 is designed to be used together with Suunto Dive Planner and Suunto Dive  
Manager. They both are PC programs for planning and managing your dive data. While  
HelO2 is used during a dive, the Dive Manager is used for uploading the dive data to your  
PC and the Dive Planner for planning any subsequent dives using the uploaded dive data  
as a basis.  
5
 
   
2. WARNINGS, CAUTIONS, AND NOTES  
Throughout this manual, important safety icons are displayed. Three classifications are  
used to separate these icons by their order of importance:  
is used in connection with a procedure or situation that could result  
in serious injury or death  
WARNING  
CAUTION  
NOTE  
is used in connection with a procedure or situation that could result  
in damage to the device  
is used to emphasize important information  
Before you go on to read the manual itself, it is extremely important that you read the fol-  
lowing warnings. These warnings are intended to maximize your safety while using Suunto  
HelO2 and must not be ignored.  
READ THIS MANUAL! Carefully read this manual in its entirety,  
paying close attention to all the warnings listed below, including  
Section 5. BEFORE DIVING. Make sure that you fully understand  
the use, displays and limitations of the dive computer, because any  
confusion resulting from neglecting to follow this user's manual or  
from improper use of this device could cause you to commit errors  
that may lead to serious injury or death.  
WARNING  
NOT FOR PROFESSIONAL USE! Suunto dive computers are inten-  
ded for recreational use only. The demands of commercial or profes-  
sional diving may expose the diver to depths and conditions that tend  
to increase the risk of decompression illness (DCI). Therefore, Suunto  
strongly recommends that the device is not used for any commercial  
or professional diving activities.  
WARNING  
ONLY DIVERS TRAINED IN THE PROPER USE OF SCUBA DIVING  
EQUIPMENT SHOULD USE A DIVE COMPUTER! No dive computer  
can replace the need for proper dive training. Insufficient or improper  
training may cause you to commit errors that may lead to serious injury  
or death.  
WARNING  
WARNING  
THERE IS ALWAYS A RISK OF DECOMPRESSION ILLNESS (DCI)  
FOR ANY DIVE PROFILE, EVEN IF YOU FOLLOW THE DIVE PLAN  
PRESCRIBED BY DIVE TABLES OR A DIVE COMPUTER. NO  
PROCEDURE, DIVE COMPUTER, OR DIVE TABLE CAN PREVENT  
THE POSSIBILITY OF DCI OR OXYGEN TOXICITY! An individual’s  
physiological make-up can vary from day to day. The dive computer  
cannot account for these variations. You are strongly advised to re-  
main well within the exposure limits provided by the instrument to  
minimize the risk of DCI. As an added precaution, you should consult  
a physician regarding your fitness before diving.  
SUUNTO STRONGLY RECOMMENDS THAT SPORT DIVERS  
LIMIT THEIR MAXIMUM DEPTH TO 40 M/130 FT OR TO THE  
DEPTH CALCULATED BY THE COMPUTER BASED ON THE SE-  
LECTED O2% AND A MAXIMUM PO2 OF 1.4 BAR!  
WARNING  
6
 
 
DIVES THAT REQUIRE DECOMPRESSION STOPS ARE NOT RE-  
COMMENDED. YOU SHOULD ASCEND AND BEGIN DECOMPRES-  
SION IMMEDIATELY WHEN THE DIVE COMPUTER SHOWS YOU  
THAT A DECOMPRESSION STOP IS REQUIRED! Note the blinking  
ASC TIME symbol and the upward pointing arrow.  
WARNING  
USE BACK-UP INSTRUMENTS! Make sure that you use back-up  
instrumentation, including a depth gauge, submersible pressure gauge,  
timer or watch, and have access to decompression tables whenever  
diving with the dive computer.  
WARNING  
WARNING  
PERFORM PRE-CHECKS! Always activate and check the device  
before diving in order to ensure that all Liquid Crystal Display (LCD)  
segments are completely displayed, that the device has not run out  
of battery power, and that the oxygen, altitude, personal, Safety/Deep  
Stop, and RGBM adjustments are correct.  
YOU ARE ADVISED TO AVOID FLYING ANY TIME THE COMPUTER  
COUNTS DOWN THE NO-FLY TIME. ALWAYS ACTIVATE THE  
COMPUTER TO CHECK THE REMAINING NO-FLY TIME PRIOR  
TO FLYING! Flying or traveling to a higher altitude within the no-fly  
time can greatly increase the risk of DCI. Review the recommendations  
given by Divers Alert Network (DAN) in Section 7.4. Flying after diving.  
WARNING  
WARNING  
THE DIVE COMPUTER SHOULD NEVER BE TRADED OR SHARED  
BETWEEN USERS WHILE IT IS IN OPERATION! Its information will  
not apply to someone who has not been wearing it throughout a dive,  
or sequence of repetitive dives. Its dive profiles must match that of  
the user. If it is left on the surface during any dive, the dive computer  
will give inaccurate information for subsequent dives. No dive com-  
puter can take into account dives made without the computer. Thus,  
any diving activity up to four days prior to initial use of the computer  
may cause misleading information and must be avoided.  
DO NOT EXPOSE THE SUUNTO HelO2'S OPTIONAL PRESSURE  
TRANSMITTER TO ANY GAS MIX CONTAINING MORE THAN 40%  
OXYGEN! Gas with greater oxygen content presents a risk of fire or  
explosion and serious injury or death.  
WARNING  
WARNING  
DO NOT DIVE WITH A GAS IF YOU HAVE NOT PERSONALLY  
VERIFIED ITS CONTENTS AND ENTERED THE ANALYZED VALUE  
INTO YOUR DIVE COMPUTER! Failure to verify cylinder contents  
and enter the appropriate O2% and He% into your dive computer will  
result in incorrect dive planning information.  
THE DIVE COMPUTER WILL NOT ACCEPT FRACTIONAL PER-  
CENTAGE VALUES OF OXYGEN CONCENTRATION. DO NOT  
ROUND UP FRACTIONAL PERCENTAGES! For example, 31.8%  
oxygen should be entered as 31%. Rounding up will cause nitrogen  
percentages to be understated and will affect decompression calcula-  
tions. If you want to adjust the computer to provide more conservative  
calculations, use the personal adjustment feature to affect decompres-  
sion calculations, or reduce the PO2 setting to affect oxygen exposure.  
WARNING  
7
 
SELECT THE CORRECT ALTITUDE ADJUSTMENT SETTING! When  
diving at altitudes greater than 300 m/1,000 ft the Altitude Adjustment  
feature must be correctly selected in order for the computer to calcu-  
late the decompression status. The dive computer is not intended for  
use at altitudes greater than 3,000 m/10,000 ft. Failure to select the  
correct Altitude Adjustment setting, or diving above the maximum  
altitude limit will result in erroneous dive and planning data.  
WARNING  
WARNING  
SELECT THE CORRECT PERSONAL ADJUSTMENT SETTING!  
Whenever it is believed that factors that tend to increase the possibility  
of DCI exist, it is recommended that you use this option to make the  
calculations more conservative. Failure to select the correct Personal  
Adjustment setting will result in erroneous dive and planning data.  
This device contains a Lithium cell battery. To reduce the risk of fire  
or burns, do not disassemble, crush, puncture, short external contacts,  
or dispose of in fire or water. Replace only with manufacturer-specified  
batteries. Recycle or dispose of used batteries properly.  
WARNING  
NOTE  
It is not possible to change between MIXED GAS and GAUGE modes  
before the instrument has counted down the no-fly time.  
8
 
3. SUUNTO HELO2 AT A GLANCE  
3.1. Navigating in the menus  
Suunto HelO2 has four main operating modes:  
1. TIME mode  
2. DIVE mode (MIXED GAS, GAUGE)  
3. PLAN mode (NODEC)  
4. MEMORY mode (HISTORY, LOGBOOK)  
To toggle between the main modes, press the MODE button. To select a submode in DIVE  
and MEMORY modes, press the UP/DOWN buttons.  
PLAN  
MEMORY  
SUB-MODE  
SUB-MODES  
Gases  
Depth Alarm  
Dive Time Alarm  
Personal/Altitude  
Sample rate  
Mixed gas  
Gauge  
NoDec  
Logbook  
History  
Tank Pressure  
Tank Pressure Alarm  
Units  
3.2. Button symbols and functions  
The table below explains the main functions of the dive computer's buttons. The buttons  
and their use is explained in more detail in the relevant sections of the manual.  
Table 3.1. Button symbols and functions  
Symbol  
Button Press Main functions  
Switch between main modes  
MODE  
Short  
Switch from submode to main mode  
Activate backlight in DIVE mode  
MODE  
Long  
Activate backlight in other modes  
Select a submode  
SELECT Short  
Select and accept settings  
Toggle between alternative displays  
Change submode  
Increase values  
UP  
Short  
Long  
Short  
UP  
Activate gas switching in MIXED GAS mode  
Toggle between alternative displays  
Change submode  
DOWN  
Decrease values  
9
 
     
Symbol  
Button Press Main functions  
Enter Setting mode  
DOWN  
Long  
10  
 
4. GETTING STARTED WITH YOUR SUUNTO HELO2  
To get the most out of your Suunto HelO2, take some time to personalize it and really  
make it YOUR computer. Set the correct time and date, tones, unit and backlight settings.  
Suunto HelO2 is a very user-friendly dive computer, and you will quickly become familiar  
with its functions. Make absolutely sure that you know your computer and have it set up  
as you want it BEFORE getting into the water.  
4.1. TIME mode settings  
The first thing you'll want to do with your Suunto HelO2, is to modify the TIME mode settings:  
the time, date, units, backlight, and tones. In this section, we look at how to do this.  
The display is illuminated by holding down the MODE button for more  
than 2 seconds.  
NOTE  
The following figure shows how to enter the TIME SETTINGS menu.  
USE UP AND DOWN BUTTONS  
UNITS, BACKLIGHT AND TONES  
TO TOGGLE BETWEEN TIME, DATE  
4.1.1. Setting the time  
In the TIME SETTING mode, you are able to set the hour, minute, and second, as well as  
choose between 12 and 24 hour display.  
ADJUST WITH UP AND  
DOWN BUTTONS. ACCEPT  
WITH SELECT BUTTON.  
4.1.2. Setting the date  
Use the DATE SETTING mode to set the year, month, and day. The day of the week is  
automatically calculated in accordance with the date.  
ADJUST WITH UP AND  
DOWN BUTTONS. ACCEPT  
WITH SELECT BUTTON.  
4.1.3. Setting the units  
In the UNITS SETTING mode you can choose to have the units displayed in either the  
metric or imperial system - meters/feet, Celsius/Fahrenheit etc.  
11  
 
         
ADJUST WITH UP AND  
DOWN BUTTONS. ACCEPT  
WITH SELECT BUTTON.  
4.1.4. Setting the backlight  
Use the BACKLIGHT SETTING mode to turn the backlight on or off and to define how  
long it stays on for (5, 10, 20, 30, or 60 seconds). When the backlight is turned off, it does  
not illuminate when an alarm sounds.  
ADJUST WITH UP AND  
DOWN BUTTONS. ACCEPT  
WITH SELECT BUTTON.  
4.1.5. Setting the tones  
The TONE SETTING mode allows you to activate or deactivate the tones.  
ADJUST WITH UP AND  
DOWN BUTTONS. ACCEPT  
WITH SELECT BUTTON.  
When the tones are off, there are no audible alarms.  
NOTE  
4.2. AC water contacts  
The water and data transfer contact is located on the rear of the case. When submerged,  
the water contact poles are connected by the conductivity of the water and the “AC” symbol  
appears on the display. The AC text is shown until the water contact deactivates.  
AC APPEARS IN THE TOP RIGHT  
CORNER OF THE DISPLAY, WHEN THE DIVE  
COMPUTER IS IN CONTACT WITH WATER.  
Contamination or dirt on the water contact may prevent this automatic activation. It is  
therefore important that the water contact is kept clean. The contact can be cleaned with  
fresh water and a soft brush, for example a tooth brush.  
12  
 
     
5. BEFORE DIVING  
Do not attempt to use the dive computer without reading this user's manual in its entirety,  
including all the warnings. Make sure that you fully understand the use, displays, and  
limitations of the instrument. If you have any questions about the manual or the Suunto  
HelO2, please contact your Suunto representative before diving with the dive computer.  
Always remember that YOU ARE RESPONSIBLE FOR YOUR OWN SAFETY!  
When used properly, Suunto HelO2 is an outstanding tool for assisting properly trained,  
certified divers in planning and executing technical dives. It is NOT A SUBSTITUTE FOR  
CERTIFIED SCUBA INSTRUCTION, including training in the principles of decompression  
and/or multi-gas diving.  
Diving with gas mixtures (nitrox, trimix, heliox, oxygen) exposes you  
to risks that are different from those associated with diving with  
standard air. These risks are not obvious, and require training to un-  
derstand and avoid. Risks include possible serious injury or death.  
WARNING  
Do not attempt to dive with any gas mix other than standard air without first receiving  
certified training in this specialty.  
5.1. Planning your dives  
The Suunto HelO2 is designed for computer-aided technical diving. You plan and modify  
your dive profiles with Suunto Dive Planner and download the gases required for the profile  
to the dive computer. During a dive, the dive computer alerts you about the gas switches  
and stops, as well as monitors the dive. The dive computer records data of the actual dive.  
After a dive you upload the data back to the Suunto Dive Planner for comparing the plan  
to the actual dive and adjusting the plan for the next dive.  
The Suunto HelO2 can store up to eight different gas mixes of oxygen, helium or nitrogen  
into its memory. The minimum O2% on the dive computer is 8%.  
With the Suunto Dive Planner you can:  
1. plan a dive including a depth plan, decompression schedule, and gas mixes for use  
during a dive.  
2. simulate the dive and create backup plans for printing them on slates. The information  
on a slate includes the gases, depth, dive time, and ascent profile.  
3. create recipes for gas mixes, either for partial pressure or continuous flow filling, and  
print them out for ordering or mixing.  
4. download gases, maximum PO2, alarms and settings to the dive computer, as well  
as confirm and set primary and secondary gases.  
5. upload data of the last dive to Suunto Dive Planner and use the data for planning the  
next dive or for comparing the actual dive to the planned one.  
After filling the cylinders with the required gas mixes, their oxygen and helium percentages  
must be analyzed and the dive computer settings modified accordingly either with the  
Suunto Dive Planner or directly in the dive computer.  
When creating a dive series, the real tissue pressures are calculated by uploading the  
actual dives to the Suunto Dive Planner with the Suunto Dive Manager. You can then plan  
the next dive based on this information.  
5.2. The Suunto Technical RGBM  
Suunto’s Reduced Gradient Bubble Model (RGBM), utilized in the Suunto HelO2, predicts  
both dissolved and free gas in the blood and tissues of divers. It is a significant advance  
on the classic Haldane models, which do not predict free gas. The advantage of Suunto  
RGBM is additional safety through its ability to adapt to a variety of situations and dive  
profiles.  
13  
 
     
YOU ARE ADVISED TO MAKE A  
DEEPSTOP AT 18 M. THE SECOND  
INDICATOR SHOWS THAT YOU HAVE 110  
SECONDS LEFT OF YOUR DEEPSTOP.  
In order to optimize the response to different increased risk situations, an additional category  
of stop, referred to as a Mandatory Safety Stop, has been introduced. The combination  
of stop types depends on the user settings and the specific dive situation.  
To get the most from the RGBM safety benefits, refer to Section 10.2. RGBM.  
5.3. Emergency ascents  
Before you dive, you must have the dive plan created with the Suunto Dive Planner printed  
out on a slate. You must also have a back-up plan for lost gases. In the unlikely event that  
the dive computer malfunctions during a dive, start using an alternative depth gauge and  
timer and following the ascent schedule and gas switches that are on the slate. If you dive  
using only air, follow these steps:  
Assess the situation calmly and then move promptly to less than 18 m/60 ft.  
At 18 m/60 ft, slow down your ascent rate to 10 m/33 ft per minute and move to a  
depth between 3 and 6 m/10 and 20 ft.  
1.  
2.  
Stay there for as long as your gas supply will safely allow. After reaching the surface,  
do not dive for at least 24 hours.  
3.  
In the event that the dive computer functions but a required gas is not available, you can  
use your diving partner's gas, which is set as a secondary gas on the dive computer.  
Displayed ASC TIME is not correct, but the decompressions are calculated correctly.  
In the event that a required gas is not available at all, decompress for as long as you can  
by using the next most suitable gas that has the highest oxygen content. Notice that the  
oxygen content should be low enough to not violate the maximum partial pressure of  
oxygen (PO2).  
5.4. Dive computer limitations  
While the dive computer's calculations are based on current decompression research and  
technology, it is important to realize that the computer cannot monitor the actual  
physiological functions of an individual diver. All decompression schedules currently known  
to the authors, including the U.S. Navy Tables, are based on theoretical mathematical  
models, which are intended to serve as a guide to reduce the probability of decompression  
illness.  
5.5. Mixed gas diving  
Diving with gas mixes provides you with an opportunity to increase bottom times, shorten  
decompression times, decrease the oxygen partial pressure at depth, and reduce the risk  
of nitrogen narcosis or decompression illness by reducing the nitrogen content in the gas  
mix.  
However, when the gas mix is altered or depth increased, the oxygen partial pressure is  
generally increased. This increase exposes the diver to an oxygen toxicity risk not usually  
considered in recreational diving. In order to manage this risk, the dive computer tracks  
the time and intensity of the oxygen exposure and provides the diver with information to  
adjust the dive plan in order to maintain oxygen exposure within reasonably safe limits.  
In addition to the physiological effects of enriched air on the body, there are operational  
considerations to be addressed when handling altered breathing mixes. Elevated concen-  
trations of oxygen present a fire or explosion hazard. Consult the manufacturer of your  
equipment to check its compatibility with nitrox.  
14  
 
     
5.6. Audible and visual alarms  
The dive computer has audible and visual alarms that advise when important limits are  
approached or that prompt you to acknowledge preset alarms. The table below describes  
the different alarms and their meanings.  
Table 5.1. Audible and visual alarm types  
Alarm indication  
Alarm reason  
Three beeps with a one second interval for PO2 value is greater than the adjusted value.  
the maximum of three minutes. The PO2  
value blinks.  
Current depth is too deep for the gas in use.  
You should immediately ascend or change  
to a gas with a lower oxygen percentage.  
Three beeps with a one second interval for PO2 value is smaller than 0.18 bar. The  
the maximum of 24 seconds. The PO2 value  
blinks.  
depth is too shallow and the ambient pres-  
sure is too low for the current gas. The oxy-  
gen content is too low to keep you con-  
scious. You should immediately switch the  
gas.  
Two beeps with a one-and-a-half second In MIXED GAS mode, the OLF value  
interval. The OLF% value blinks if the PO2 reaches the fixed 80% or 100%. You can  
acknowledge the alarm.  
value is greater than 0.5 bar.  
Two beeps with a one-and-a-half second Decompression ceiling depth is exceeded.  
interval for three minutes. The Er symbol You should immediately descend to, or be-  
blinks and an arrow points downwards.  
low, the ceiling.  
Two beeps with a one-and-a-half second Mandatory safety stop is violated. You  
interval for three minutes. An arrow points should immediately descend.  
downwards.  
Three beeps with a one second interval for Maximum allowed ascent rate, 10 m per min  
24 seconds. The SLOW symbol blinks.  
/ 33 ft per min, is exceeded.  
Two beeps with a one and a half second in- Mandatory deepstop is violated. You should  
terval for the duration of the deepstop viola- immediately descend.  
tion. DEEPSTOP blinks and an arrow points  
downwards.  
Two beeps with a one-and-a-half second Cylinder pressure reaches the selected  
interval. Tank pressure blinks.  
alarm pressure, 10 - 200 bar.  
Cylinder pressure reaches the fixed alarm  
pressure, 50 bar.  
Two beeps with a one-and-a-half second No-decompression dive turns into a decom-  
interval for 24 seconds. ASC TIME blinks pression stop dive.  
and an arrow points upwards.  
Depth is below the decompression floor  
level. You should immediately ascend to, or  
above, the floor.  
Two beeps with a one-and-a-half second Gas change is required. You should imme-  
interval. Gas mix value (O2%, O2%|He%) diately change to a gas more favorable to  
decompression. ASC TIME assumes that  
the gas is changed immediately and is accur-  
ate only if you change the gas.  
blinks.  
Three beeps with a one second interval.  
The deepstop depth is reached. Make the  
mandatory deepstop for the duration shown  
by the timer.  
15  
 
 
Alarm indication  
Alarm reason  
Three beeps with a one second interval for The selected depth (3 - 120 m / 10 - 394 ft)  
24 seconds. Maximum depth blinks.  
is exceeded.  
The fixed maximum depth (120 m / 394 ft)  
is exceeded.  
Three beeps with a one second interval for The selected dive time (1 - 999 min) is ex-  
24 seconds. Dive time blinks. ceeded.  
When the backlight is turned OFF, it does not illuminate when an  
alarm is activated.  
NOTE  
WHEN THE OXYGEN LIMIT FRACTION INDICATES THAT THE  
MAXIMUM LIMIT IS REACHED, YOU MUST IMMEDIATELY TAKE  
ACTION TO REDUCE OXYGEN EXPOSURE. Failure to take action  
to reduce oxygen exposure after the warning is given can rapidly in-  
crease the risk of oxygen toxicity, injury, or death.  
WARNING  
5.7. Error conditions  
The dive computer has warning indicators that alert you to react to certain situations that  
would significantly increase the risk of DCI. If you do not respond to its warnings, the dive  
computer will enter an Error mode, indicating that the risk of DCI has greatly increased.  
If you understand the dive computer and operate it sensibly, it is very unlikely you will ever  
put the instrument into the Error mode.  
Out of calculation limits  
Suunto uses state of the art memory and microprocessors, however, there are limitations  
to the memory capacity of decompression calculations. Therefore Suunto must limit the  
maximum saturation of tissues on Suunto HelO2 and limit the maximum bottom times on  
dives performed using the dive computer. The bottom times include decompression calcu-  
lation. While it is highly unlikely that the following bottom times are confronted by open-  
circuit divers, it is important to warn you of their possibility.  
The same limits are used in the Suunto Dive Planner and so repetitive dives will be checked  
while planning a dive because a dive plan must be created in any case.  
Table 5.2. Possible decompression dive times  
Gas mix  
O2%/He%  
Depth  
Bottom time Ceiling  
First deep-  
stop  
Tx  
Tx  
Tx  
Tx  
20/35  
15/50  
12/60  
10/60  
60 m  
250 min  
260 min  
120 min  
90 min  
33 m  
50 m  
61 m  
73 m  
46 m  
65 m  
80 m  
96 m  
80 m  
100 m  
120 m  
Descent at the rate of 10 m/min is included in the time. The times allow for a safe ascent  
using the bottom gas all the way to the surface without exceeding tissue pressures.  
If a diver violates these limits, the dive computer goes to an error mode and the rest of  
the dive must be conducted using the diveplan on the slate.  
16  
 
 
Omitted decompression  
The Error mode results from omitted decompression, i.e. when you stay above the ceiling  
for more than three minutes. During this three-minute period the Er warning is shown and  
the audible alarm beeps. After this, the dive computer will enter a permanent Error mode.  
The instrument will continue to function normally if you descend below the ceiling within  
this three-minute period.  
Once in the permanent Error mode, only the Er warning is shown in the center window.  
The dive computer will not show times for ascent or stops. However, all the other displays  
will function as before to provide information for ascent.You should immediately follow  
through the decompression schedule in your backup plan.  
After surfacing, you should not dive for a minimum of 48 hours. During the permanent  
Error mode, the Er text will be displayed in the center window and the planning mode will  
be disabled.  
5.8. Wireless transmission  
The HelO2 can be used together with a wireless cylinder pressure transmitter that easily  
attaches to the high-pressure port of the regulator. By using the transmitter, you can be-  
nefit from receiving cylinder pressure data direct to your wrist.  
In order to use the transmitter, the wireless integration needs to be enabled in your Suunto  
HelO2 settings. To enable or disable the wireless integration refer to Section 5.9.7. Setting  
the tank pressure.  
5.8.1. Installing the wireless transmitter  
When purchasing the Suunto HelO2, we strongly recommend that you have your Suunto  
representative attach the transmitter to the first stage of your regulator.  
However, if you decide to attach it yourself, do the following:  
Remove the high pressure (HP) port plug on the first stage of your regulator using an  
appropriate tool.  
1.  
Thread the high pressure transmitter of the Suunto into the HP port of your regulator  
with your fingers. DO NOT OVERTIGHTEN! Maximum torque is 6 Nm/4.4 lbsft or 53  
lbsin. The seal is based on a static O-ring, not force!  
2.  
Attach the regulator to the scuba cylinder and slowly open the valve. Check for leaks  
by submerging the regulator first stage in water. If leaks are detected, check the  
condition of the O-ring and sealing surfaces.  
3.  
5.8.2. Pairing and code selection  
In order to receive wireless data, the transmitter and the Suunto HelO2 need to be paired.  
During the pairing procedure, the transmitter and dive computer select a common trans-  
mission code.  
The transmitter is activated when the pressure exceeds 15bar/218 psi and it then starts  
sending pressure data together with a code number. During the pairing procedure, the  
Suunto HelO2 stores the code number and starts displaying pressure values that are re-  
ceived with that code. This coding procedure inhibits data mix-up from other divers also  
using a Suunto HelO2 transmitter.  
When there is no stored code, the Suunto HelO2 displays “cd:--” and receives data with  
lowered sensitivity from a very short distance only. By taking the Suunto HelO2 close to  
the transmitter, it will store the received code and start receiving with full sensitivity and  
display data received with this code only. The code is stored until you reset it manually.  
To pair the transmitter and the Suunto HelO2 dive computer:  
Make sure that the transmitter is properly attached to the regulator’s HP port and that  
the regulator is properly attached to the cylinder.  
1.  
17  
 
     
Ensure that the Suunto HelO2 is turned on, and that the wireless integration is enabled  
in the Suunto HelO2 settings (HP set ON, see Section 5.9.8. Setting the HP code).  
The HelO2 should display “cd:--” in the lower left corner of the alternative display.  
Slowly open the cylinder valve fully and pressurize the regulator. The transmitter starts  
transmitting when the pressure exceeds 15 bar/218 psi.  
Take the Suunto HelO2 wrist unit close to the transmitter. The unit will then quickly  
display the selected code number and then start displaying the transmitted cylinder  
pressure. The wireless transmitter indicator is displayed every time the Suunto receives  
a valid signal.  
2.  
3.  
4.  
If there are several divers using Suunto HelO2 with wireless transmis-  
sion, always ensure that each diver is using a different code before  
starting the dive.  
WARNING  
You can manually change the transmitter’s code by reducing the  
pressure to less than 10 bar/145 psi and then immediately (within 10-  
12 seconds) increasing the pressure to above 15 bar/220 psi.  
Reset the transmitter's code manually, see Section 5.9.8. Setting the  
HP code.  
The transmitter will then select a new code. The Suunto HelO2 must  
be in “cd:--“ mode to pair on the new code. This procedure can be  
used if, for example, your dive buddy has the same code and you  
need to change it.  
In order to save battery energy, the transmitter shuts off if the pressure  
remains unchanged for more than 10 minutes, and it will continue  
transmitting with the saved code when any pressure change is  
measured.  
NOTE  
5.8.3. Transmitting data  
After the pairing procedure, the Suunto HelO2 will receive cylinder pressure data from the  
transmitter. The pressure is displayed in either bars or psi, depending on the unit selected.  
Any time the Suunto HelO2 receives an appropriate signal it flashes the wireless transmitter  
indicator in the display’s lower left corner.  
Table 5.3. Pressure transmission related displays  
Display Indication  
Figure  
Set Code. No code stored, Suunto HelO2 ready for pairing with trans-  
Cd:--  
A
mitter.  
Pressure reading over 360 bar/5220 psi.  
- - -  
B
C
Pressure reading has not been updated for more than one minute.  
The latest valid pressure reading is displayed intermittently. After five  
minutes, "FAIL" is displayed intermittently with "---".  
FAIL  
Transmitter is out of range, in power saving mode or on another  
channel. Activate the transmitter by breathing off the regulator, and  
recode the wrist unit if necessary.  
Pressure transmitter battery voltage is low. The pressure reading is  
displayed intermittently. Change the transmitter battery!  
LOb  
OFF  
D
E
Pairing has not been conducted between the dive computer and the  
transmitter before start of dive. No cylinder data available.  
18  
 
 
A
B
C
D
E
5.9. MIXED GAS DIVE mode settings  
Suunto HelO2 has several user-definable functions, as well as depth and time-related  
alarms that you can set according to your personal preferences. The DIVE mode settings  
are dependent on the dive submode chosen (MIXED GAS, GAUGE), so that, for example,  
gas mix settings are only available in the MIXED GAS submode.  
With Suunto HelO2, most of the settings are planned with the Suunto Dive Planner and  
downloaded to the dive computer. If necessary, they can be changed manually.  
The following figure shows how to enter the DIVE mode settings menu.  
USE UP AND DOWN BUTTONS  
TO  
TOGGLE BETWEEN DIVE SETTINGS  
Some settings cannot be changed until 5 minutes has elapsed after  
the dive.  
NOTE  
5.9.1. Setting the gases  
If set to the MIXED GAS mode, the correct oxygen and helium percentages of the gas in  
your cylinders (and additional gases) must always be entered into the dive computer to  
ensure correct tissue and oxygen calculation. In addition, the oxygen partial pressure  
limit must be set. You can either modify the dive plan with the Suunto Dive Planner or  
enter the correct values directly into the dive computer after analyzing the gas mixes in  
your cylinders.  
ADJUST WITH  
UP AND DOWN  
BUTTONS.  
ADJUST WITH  
UP AND DOWN  
BUTTONS.  
ACCEPT WITH  
SELECT BUTTON.  
ACCEPT WITH  
SELECT BUTTON.  
When in the MIXED GAS setting mode, the equivalent maximum operating depth, based  
on the chosen setting, is also be displayed.  
After entering values for MIX1, you can set additional mixes, MIX2 - MIX8, similarly. You  
can set them to "PRIMARY", "SECONDARY" or "OFF". MIX 1 is always set as a primary  
gas.  
In order to minimize the risk of error during a dive, it is highly recommended that the mixes  
are set in the proper order. This means that as the mix number rises, so does oxygen  
content, and this is the order they are usually used during the dive. Before a dive, only  
enable the mixes you actually have available and remember to check the set values to  
make sure they are correct.  
19  
 
   
The ASC time is calculated based on the assumption that you start the ascent profile im-  
mediately and all the PRIMARY gases are changed as soon as their maximum operating  
depth allows it. That is, using the gases that are set as primary, the most optimal ascent  
schedule for the moment is calculated.  
To see the most pessimistic ascent schedule, that is, a schedule for the situation when  
gases are not changed at all, you can set the gases as secondary and the time it takes to  
finish the decompression using the current breathing gas is shown as the ASC time.  
Showing the most pessimistic ascent schedule during a long dive can easily result in the  
ascent time no longer fitting the reserved field and the dive computer displays "---" (max.  
199 min).  
While setting the gases, notice that the calculated maximum operating  
depth is displayed in the upper field. You cannot change to this gas  
before you have ascended above this depth.  
NOTE  
The default oxygen percentage (O2%) setting is 21% (air) and oxygen partial pressure  
(PO2) setting 1.4 bar.  
5.9.2. Setting the depth alarm  
You can set a depth alarm in the dive computer.  
ADJUST WITH UP AND  
DOWN BUTTONS. ACCEPT  
WITH SELECT BUTTON.  
The depth alarm is factory-set to 50 m/160 ft, but you can adjust it according to your per-  
sonal preference, or switch it off altogether. The depth range can be set from 3 m to 120  
m/10 ft to 394 ft.  
5.9.3. Setting the dive-time alarm  
The Suunto HelO2 has a dive-time alarm setting which, when activated, can be used for  
several purposes to add to your diving safety.  
ADJUST WITH UP AND  
DOWN BUTTONS. ACCEPT  
WITH SELECT BUTTON.  
With a range of 1 - 999 minutes, the alarm can be set to your planned  
bottom time, for example.  
NOTE  
5.9.4. Setting the personal/altitude adjustments  
The current Altitude and Personal Adjustment settings are displayed in the startup screen  
when entering the DIVE mode. If the mode does not match the altitude or personal condi-  
tions (see Section 5.10.4. Diving at altitude and Section 5.10.5. Personal adjustments), it  
is imperative that you enter the correct selection before diving. Use Altitude Adjustment  
to select the correct altitude and use Personal Adjustment to add an extra level of conser-  
vatism or aggressiveness.  
20  
 
     
ADJUST WITH UP AND  
DOWN BUTTONS. ACCEPT  
WITH SELECT BUTTON.  
5.9.5. Setting the sample rate  
The sample rate controls how often the depth, time, tank pressure, and water temperature  
is stored in the memory.  
You can set the dive profile sample rate to 10, 20, 30, or 60 seconds. The factory default  
setting is 20 seconds.  
ADJUST WITH UP AND  
DOWN BUTTONS. ACCEPT  
WITH SELECT BUTTON.  
5.9.6. Setting the tank pressure alarm  
The tank pressure alarm can be set "ON" or "OFF" and in the range of 10 - 200 bar. The  
alarm is the secondary cylinder pressure alarm point. The alarm is activated when the  
tank pressure drops below the set limit. You can acknowledge this alarm.  
The 50 bar alarm, however, is fixed and cannot be changed. You cannot acknowledge  
this alarm.  
ADJUST WITH UP AND  
DOWN BUTTONS. ACCEPT  
WITH SELECT BUTTON.  
5.9.7. Setting the tank pressure  
The wireless transmission can be set “ON” or “OFF” depending whether the wireless  
pressure transmitter is used or not. No cylinder pressure-related data is shown, nor data  
reception made, when this selection is “OFF”.  
ADJUST WITH UP AND  
DOWN BUTTONS. ACCEPT  
WITH SELECT BUTTON.  
5.9.8. Setting the HP code  
The HP Code setting allows you to verify the selected code and to erase the stored code.  
It also enables re-pairing if necessary.  
21  
 
       
ADJUST WITH UP AND  
DOWN BUTTONS. ACCEPT  
WITH SELECT BUTTON.  
SELECT TANK  
PRESSURE ON.  
5.9.9. Setting the units  
Use Unit Settings to choose between metric (meters/celsius/bar) and imperial  
(feet/fahrenheit/psi) units.  
ADJUST WITH UP AND  
DOWN BUTTONS. ACCEPT  
WITH SELECT BUTTON.  
5.10. Activation and pre-checks  
This section describes how to activate the DIVE mode and explains the pre-checks that  
it is highly recommended you perform before you get into the water.  
5.10.1. Accessing DIVE mode  
The Suunto HelO2 has two diving modes: MIXED GAS mode for diving with gas mixes  
and GAUGE mode for use as a bottom timer.  
The chosen dive mode is displayed when the DIVE mode is accessed, and you can toggle  
between the submodes by pressing the UP/DOWN buttons.  
5.10.2. DIVE mode activation  
The dive computer activates automatically when submerged deeper than 0.5 m/1.5 ft.  
However, it is necessary to activate the DIVE mode BEFORE diving to check the  
altitude and personal adjustment settings, battery condition, oxygen settings etc.  
After activation, all graphical display elements are turned on, and the backlight and the  
beep are activated. A few seconds later the battery power indicator is shown.  
At this time, perform your pre-checks, making sure that:  
the instrument operates in the correct mode and provides a complete display (MIXED  
GAS/GAUGE mode)  
the battery level is ok  
22  
 
       
the altitude and personal adjustment settings are correct  
the instrument displays correct units of measurement (Metric/Imperial)  
the instrument displays the correct temperature and depth (0.0 m/0 ft)  
the alarm beeps  
If the optional wireless pressure transmitter is used ensure that:  
the pressure transmitter has been properly attached and the cylinder valve is open  
the transmitter and the wrist unit have been properly paired on a suitable code  
the pressure transmitter is working (wireless transmitter indicator blinks, cylinder  
pressure is displayed), and that there is no low battery warning displayed  
you have enough gas for your planned dive. You should also check the pressure  
reading against your back-up pressure gauge  
And, if set to MIXED GAS mode, make sure that:  
the oxygen partial pressure limits are set correctly  
For more information on the MIXED GAS mode, refer to Section 6.2. Diving in MIXED  
GAS mode .  
The dive computer is now ready for diving.  
5.10.3. Battery power indication  
Temperature or internal oxidation of the battery affect the battery voltage. If the instrument  
is stored for a long period, or used in cold temperatures, the low battery warning may be  
displayed even though the battery has enough capacity. In these cases, re-enter DIVE  
mode to receive the battery power indication.  
After the battery check, the low battery warning is indicated by the battery symbol.  
If the battery symbol is displayed in the Surface mode, or if the display is faded or weak,  
the battery may be too low to operate the dive computer, and battery replacement is re-  
commended.  
For safety reasons, the backlight cannot be activated when the low  
battery warning is indicated by the battery symbol.  
NOTE  
The optional wireless pressure transmitter sends out a low battery (LOb) warning when  
its battery voltage is getting low. This is shown intermittently instead of the pressure  
reading. When you get this warning, the pressure transmitter's battery needs to be replaced.  
5.10.4. Diving at altitude  
The dive computer can be adjusted both for diving at altitude and also to increase the  
conservatism of the mathematical nitrogen model.  
When programming the instrument for the correct altitude, you need to select the correct  
Altitude Adjustment settings according to Table 5.4, Altitude Adjustment settings. The dive  
computer will adjust its mathematical model according to the entered altitude setting, giving  
shorter no-decompression times at higher altitudes.  
Table 5.4. Altitude Adjustment settings  
Alt. adjustment value  
Altitude range  
A0  
A1  
0 - 300 m / 0 - 1000 ft  
300 - 1500 m / 1000 - 5000 ft  
23  
 
   
Alt. adjustment value  
Altitude range  
A2  
1500 - 3000 m / 5000 - 10 000 ft  
Section 5.9.4. Setting the personal/altitude adjustments describes  
how the Altitude value is set.  
NOTE  
Traveling to a higher elevation can temporarily cause a change in the  
equilibrium of dissolved nitrogen in the body. It is recommended that  
you acclimatize to the new altitude by waiting at least three hours  
before diving.  
WARNING  
5.10.5. Personal adjustments  
There are personal factors that can affect your susceptibility to DCI, which you can predict  
in advance, and input into the decompression model. Such factors vary between divers  
and also for the same diver from one day to another. The five-step Personal Adjustment  
setting is available if a more conservative or aggressive dive plan is desired.  
The personal factors which tend to increase the possibility of DCI include, but are not  
limited to:  
cold exposure - water temperature less than 20 °C/68 °F  
below average physical fitness level  
fatigue  
dehydration  
previous history of DCI  
stress  
obesity  
patent foramen ovale (PFO)  
exercise on or after dive  
This feature is used to adjust the computer to be more conservative, according to personal  
preference, by entering the suitable Personal Adjustment setting with the help of Table 5.5,  
Personal Adjustment settings. In ideal conditions, retain the default setting, P0. If conditions  
are more difficult, or any of the factors which tend to increase the possibility of DCI exist,  
select P1, or even the most conservative P2. For very experienced divers willing to take  
high personal risks and full responsibility of their own condition, two negative values of  
the personal adjustments, P-2 and P-1, exist.The dive computer then adjusts its mathem-  
atical model according to the entered Personal Adjustment setting, giving shorter no-de-  
compression times.  
Table 5.5. Personal Adjustment settings  
Personal adjust-  
ment value  
Condition  
Desired tables  
P-2  
P-1  
P0  
Ideal conditions, excellent physical Progressively less conservative  
fitness, highly experienced with a lot  
of dives in the near past  
Ideal conditions, good physical fit-  
ness, well experienced with dives in  
the near past  
Ideal conditions  
Default  
24  
 
 
Personal adjust-  
ment value  
Condition  
Desired tables  
P1  
P2  
Some risk factors or conditions exist Progressively more conservative  
Several risk factors or conditions  
exist  
Personal adjustment setting P0 – P-2 causes a high risk of DCI, or  
other personal injury, and death.  
WARNING  
5.11. Safety Stops  
Safety Stops are widely considered good diving practice for recreational and technical  
diving, and are an integral part of most dive tables. The reasons for performing a Safety  
Stop include: reducing sub-clinical DCI, microbubble reduction, ascent control, and orient-  
ation before surfacing.  
The Suunto HelO2 displays two different types of Safety Stops: Recommended Safety  
Stop and Mandatory Safety Stop.  
5.11.1. Recommended Safety Stops  
With every dive over 10 meters, there is a three minute countdown for the Recommended  
Safety Stop, to be taken in the 6 - 3 m/10 ft - 20 ft range. This is shown with the STOP  
sign and a three-minute countdown in the center window instead of the no-decompression  
time.  
WHEN STOP IS DISPLAYED,  
MAKE A RECOMMENDED SAFETY  
STOP FOR 3 MINUTES.  
The Recommended Safety Stop, as the name implies, is recommen-  
ded. If it is ignored, there is no penalty applied to the following surface  
intervals and dives.  
NOTE  
5.11.2. Mandatory Safety Stops  
When the ascent rate exceeds 10 m/33 ft per minute continuously for more than 5 seconds,  
the microbubble build-up is predicted to be more than is allowed for in the decompression  
model. The Suunto RGBM calculation model responds to this by adding a Mandatory  
Safety Stop to the dive. The time of this Mandatory Safety Stop depends on the severity  
of the ascent rate excess.  
The STOP sign appears in the display and when you reach the depth zone between 6 m  
and 3 m/20 ft and 10 ft, the CEILING label, ceiling depth, and the calculated Safety Stop  
time also appear in the display. You should wait until the Mandatory Safety Stop warning  
disappears. The total length of the Mandatory Safety Stop time depends on the seriousness  
of the ascent rate violation.  
25  
 
     
WHEN CEILING AND STOP ARE  
DISPLAYED, MAKE A ONE MINUTE  
MANDATORY SAFETY STOP IN THE  
DEPTH ZONE BETWEEN 6 M AND 3 M.  
You must not ascend shallower than 3 m/10 ft with the Mandatory Safety Stop warning  
on. If you ascend above the Mandatory Safety Stop ceiling, a downward pointing arrow  
will appear and a continuous beeping starts. You should immediately descend to, or below,  
the Mandatory Safety Stop ceiling depth. If you correct this situation at any time during  
the dive, there are no effects on the decompression calculations for future dives.  
WHEN CEILING AND STOP  
ARE DISPLAYED, IMMEDIATELY  
(WITHIN 3 MINUTES) DESCEND  
TO OR BELOW CEILING.  
If you continue to violate the Mandatory Safety Stop, the tissue calculation model is affected  
and the dive computer shortens the available no-decompression time for your next dive.  
In this situation, it is recommended that you prolong your surface interval time before your  
next dive.  
5.12. Deep stops  
The most significant factor limiting the ascent is the ceiling depth. It is the maximum depth  
a diver can ascend to before tissue pressures have decreased low enough. In addtion,  
separate safety stops are used. Their purpose is to increase the safety margin even if  
decreasing the tissue pressures does not require them. Such stops are safety stop when  
surfacing and deep stops.  
According to UHMS, deep stops are stops that occur deeper than the traditional decom-  
pression model suggests. The purpose of deep stops is to slow down a long continuous  
ascent and minimize microbubble formation and excitation.  
While the Suunto Technical RGBM model is based on M-values, the use of deep stops  
brings the model closer to the full RGBM model. The way of implementing deep stops is  
conducted by Dr. Bruce Wienke.  
If deep stop is broken it does not cause the dive computer to go into error mode. However  
there is penalty applied to the following decompressions.  
DURING ASCENT, YOU  
DURING DESCENT,  
YOU ARE SHOWN  
THAT A DEEPSTOP IS  
NEEDED AT THE  
ARE ADVISED TO MAKE A  
DEEPSTOP AT 25 M FOR THE  
DURATION SHOWN BY THE  
TIMER (42 SEC. REMAINING).  
DEPTH OF 25 M.  
26  
 
 
6. DIVING  
This section contains instructions on how to operate the dive computer and interpret its  
displays. You’ll find that this dive computer is easy to use and read. Each display shows  
only the data relevant to that specific diving mode.  
6.1. Diving-related information  
In this section, we look at how to make the most of the dive computer when diving with  
gas mixes. To activate MIXED GAS DIVE mode, please see Section 5.10.1. Accessing  
DIVE mode.  
DIVE HAS JUST BEGUN AND  
AVAILABLE NO-DECOMPRESSION  
TIME IS OVER 199 MINUTES SO NO  
VALUE IS DISPLAYED.  
The dive computer will remain in the Surface mode at depths less  
than 1.2 m/4 ft. At depths greater than 1.2 m/4 ft the instrument will  
go into the DIVE mode automatically. However, it is recommended  
that you activate the Surface mode manually before entering the water  
in order to perform the necessary dive pre-checks.  
NOTE  
NOTE  
The default fields shown on your dive computer in diving mode are  
the ones you select while in surface mode.  
6.1.1. Basic dive data  
During a No-decompression dive, the following information is displayed:  
your present depth in meters/feet  
the available no-decompression time in minutes as NO DEC TIME  
the ascent rate presented as a bar graph on the right side  
DIVE DISPLAY - PRESENT DEPTH IS 15 M,  
MAX DEPTH OF DIVE IS 33.5 M AND  
NO-DECOMPRESSION STOP TIME LIMIT IS 38 MIN.  
ELAPSED DIVE TIME IS 13 MIN.  
Alternative displays, by pressing the UP/DOWN buttons, show:  
the elapsed dive time in minutes, shown as DIVE TIME  
the water temperature in °C/°F  
the maximum depth during this dive in meters/feet, indicated as MAX  
the current time, shown as TIME  
UP BUTTON TOGGLES  
BETWEEN DIVE TIME AND  
WATER TEMPERATURE.  
In addition, with the optional wireless transmission enabled:  
the cylinder pressure in bar (or psi) displayed in the lower left corner  
the cylinder pressure graphically displayed on the left side  
27  
 
     
6.1.2. Bookmark  
It is possible to record bookmarks in the profile memory during a dive. These bookmarks  
are displayed when scrolling the profile memory on the display. The bookmarks will also  
be shown as annotations in the downloadable Suunto Dive Manager PC software.  
The bookmark logs the depth, time, water temperature, and tank pressure when available.  
To make a bookmark in the profile memory during a dive, press the SELECT button. A  
brief confirmation will be given.  
A BOOKMARK IS PLACED  
IN THE PROFILE MEMORY  
DURING A DIVE BY PRESSING  
THE SELECT BUTTON.  
6.1.3. Ascent rate indicator  
The ascent rate is shown graphically along the right hand side. When the maximum allowed  
ascent rate is exceeded, the lower segments start to blink with the top segment staying  
solid, indicating that the maximum ascent rate has been exceeded continuously or that  
the current ascent rate is significantly above the allowed rate.  
ACTIVATED BACKLIGHT,  
ALARM AND A BLINKING ASCENT  
RATE BAR GRAPH INDICATE YOU  
ARE ASCENDING FASTER THAN 10  
M/MIN. YOU ARE ADVISED TO  
MAKE A MANDATORY SAFETY  
STOP WHEN YOU REACH A  
DEPTH OF 6 M.  
NORMAL  
ASCENT  
RATE.  
DO NOT EXCEED THE MAXIMUM ASCENT RATE! Rapid ascents  
increase the risk of injury. You should always make the Mandatory  
and Recommended Safety Stops after you have exceeded the max-  
imum recommended ascent rate. If this Mandatory Safety Stop is not  
completed, the decompression model will penalize your next dive(s).  
Continuous ascent rate violations will result in Mandatory Safety Stops.  
When Recommended Deep Stop is enabled, the length is indicated  
in seconds.  
WARNING  
6.1.4. Safety Stops  
A 3 minute Recommended Safety Stop is prompted after every dive to over 10m.  
6.1.5. Decompression dives  
When your NO DEC TIME becomes zero, your dive becomes a decompression dive so  
you must perform one or more decompression stops on your way to the surface. The NO  
DEC TIME on your display will be replaced by an ASC TIME, and a CEILING notation will  
appear. An upward pointing arrow will also prompt you to start your ascent.  
If you exceed the no-decompression limits on a dive, the dive computer will provide the  
decompression information required for ascent. After this, the instrument will continue to  
provide subsequent interval and repetitive dive information.  
Rather than requiring you to make stops at fixed depths, the dive computer lets you de-  
compress within a range of depths (continuous decompression).  
28  
 
       
The ascent time (ASC TIME) is the minimum amount of time needed to reach the surface  
in a decompression dive. It includes:  
the time needed at the deep stop  
the time needed to ascend to the ceiling at an ascent rate of 10 m/33 ft per minute.  
The ceiling is the shallowest depth to which you should ascend  
the time needed at the ceiling  
the time needed at the Mandatory Safety Stop (if any)  
the time needed to reach the surface after the ceiling and Safety Stops have been  
completed  
YOUR ACTUAL ASCENT TIME MAY BE LONGER THAN DIS-  
PLAYED BY THE INSTRUMENT! The ascent time will increase if  
you:  
WARNING  
remain at depth  
ascend slower than 10 m/33 ft per minute  
make your decompression stop deeper than at the ceiling  
do not use optimal decompression gas  
These factors will also increase the amount of gas required to reach  
the surface.  
Ceiling, ceiling zone, floor and decompression range  
When in decompression, it is important that you understand the meaning of ceiling, floor,  
and decompression range.  
The ceiling is the shallowest depth to which you should ascend when in decompression.  
At this depth, or below, you must perform all stops  
The ceiling zone is the optimum decompression stop zone. It is the zone between the  
minimum ceiling and 1.2 m/4 ft below the minimum ceiling  
The floor is the deepest depth at which the decompression stop time will not increase.  
Decompression will start when you pass this depth during your ascent  
The decompression range is the depth range between the ceiling and floor. Within this  
range, decompression takes place. However, it is important to remember that the de-  
compression will be very slow at, or close to, the floor  
The depth of the ceiling and floor will depend on your dive profile. The ceiling depth will  
be fairly shallow when you enter the decompression mode, but if you remain at depth, it  
will move downward and the ascent time will increase. Likewise, the floor and ceiling may  
change upwards while you are decompressing.  
When conditions are rough, it may be difficult to maintain a constant depth near the surface.  
In such cases, it is more manageable to maintain an additional distance below the ceiling,  
to make sure that the waves do not lift you above the ceiling. Suunto recommends that  
decompression takes place deeper than 4 m/13 ft, even if the indicated ceiling is shallower.  
It will take more time and more gas to decompress below the ceiling  
than at the ceiling.  
NOTE  
29  
 
NEVER ASCEND ABOVE THE CEILING! You must not ascend above  
the ceiling during your decompression. In order to avoid doing so by  
accident, you should stay somewhat below the ceiling.  
WARNING  
Display below the floor  
The blinking ASC TIME and an upward pointing arrow indicate that you are below the  
floor. The ceiling depth is shown on the left side, and the minimum total ascent time on  
the right side, of the center window. Below is an example of a decompression dive above  
Deep Stops, below the floor.  
UPWARD POINTING ARROW, BLINKING ASC  
TIME AND AN ALARM TELL YOU TO ASCEND. MINIMUM  
TOTAL ASCENT TIME INCLUDING MANDATORY SAFETY  
STOP IS 15 MINUTES. CEILING IS AT 3 M.  
Display above the floor  
When you ascend above the floor, the ASC TIME display stops blinking and the upward  
pointing arrow disappears. Below is an example of a decompression dive above the floor.  
UPWARD POINTING ARROW HAS  
DISAPPEARED AND ASC TIME LABEL HAS  
STOPPED BLINKING, MEANING YOU ARE IN  
THE DECOMPRESSION RANGE.  
Decompression will now begin, but is very slow. You should therefore continue your ascent.  
Display at the ceiling zone  
When you reach the ceiling zone, the display will show you two arrows pointing at each  
other (the “hour glass” icon). Below is an example of a decompression dive at the ceiling  
zone.  
TWO ARROWS POINT AT EACH OTHER  
“HOUR GLASS. YOU ARE IN THE OPTIMUM CEILING  
ZONE AT 3 M.AND YOUR MINIMUM ASCENT TIME IS  
15 MINUTES.  
During the decompression stop, ASC TIME will count down towards zero. When the ceiling  
moves upwards, you can ascend to the new ceiling. You may surface only after the ASC  
TIME and CEILING labels have disappeared, which means that the decompression stop  
and any Mandatory Safety Stop have been completed. You are advised, however, to stay  
until the STOP sign has also disappeared. This indicates that the three minute Recommen-  
ded Safety Stop has also been completed.  
Display above the ceiling  
If you ascend above the ceiling during a decompression stop, a downward pointing arrow  
will appear and a continuous beeping starts.  
30  
 
DECOMPRESSION DIVE,ABOVE CEILING.  
NOTE DOWNWARD POINTING ARROW, ER WARNING  
AND ALARM. YOU SHOULD IMMEDIATLY (WITHIN  
3 MINUTES) DESCEND TO OR BELOW CEILING.  
In addition, an Error warning (Er) reminds you that you have only three minutes to correct  
the situation. You must immediately descend to, or below, the ceiling.  
If you continue to violate the decompression, the dive computer will go into a permanent  
Error Mode. In this mode, the instrument can only be used as a depth gauge and timer.  
You must not dive again for at least 48 hours. (See Section 5.7. Error conditions).  
6.2. Diving in MIXED GAS mode  
MIXED GAS mode is the first dive mode available in Suunto HelO2. The mode is used  
when diving with air or with oxygen- or helium-enriched gas mixes.  
6.2.1. Before diving in MIXED GAS mode  
If set to the MIXED GAS mode, the correct oxygen and helium percentage of the gas in  
your cylinders must always be entered into the computer to ensure correct inert gas and  
oxygen calculations. The dive computer adjusts its mathematical inert gas and oxygen  
calculation models accordingly. The dive computer will not accept fractional percentage  
values of oxygen and helium concentration. Do not round up fractional percentages. For  
example, 31.8% oxygen should be entered as 31%. Rounding up will cause inert gas  
percentages to be understated and will affect decompression calculations. If you want to  
adjust the computer to provide more conservative calculations, use the personal adjustment  
feature to affect decompression calculations, or reduce the PO2 setting to affect oxygen  
exposure according to the entered O2% and PO2 values. Calculations based on nitrox use  
result in longer no-decompression times and shallower maximum depths than diving with  
air.  
As a safety precaution, the oxygen calculations in the computer are made with an oxygen  
percentage of 1% + set O2% .  
When the dive computer is set in MIXED GAS mode, the Dive Planning mode calculates  
using the O2% and PO2 values that are currently in the computer.  
To set the nitrox, trimix and/or or heliox mixes, refer to Section 5.9.1. Setting the gases.  
Default gas mix settings  
In MIXED GAS mode, the Suunto HelO2 allows you to set 1 – 8 gas mixes containing 8 –  
99% oxygen and 0 – 92% helium.  
In the MIXED GAS mode, the default setting is standard air (21% O2 and 0% He). It remains  
in this setting until the O2% is adjusted to any other percentage of oxygen (8% – 99%).  
The default setting for maximum oxygen partial pressure is 1.4 bar, however you are able  
to set it in the range of 0.5 - 1.6 bar.  
6.2.2. Oxygen and helium displays  
When MIXED GAS mode is activated, the display will show the information in the figure  
below. In MIXED GAS mode, the maximum operational depth is calculated based on set  
O2%, He% and PO2 values.  
31  
 
     
MIXED GAS DIVE MODE ACTIVATION,  
MAXIMUM OPERATIONAL DEPTH BASED ON  
SET O2% (14%), HE2% (32%), AND PO2 (1.4) IS  
83.3 M.  
If set to MIXED GAS mode, the Suunto HelO2 will additionally show on the alternative  
display:  
the oxygen percentage, labeled O2%  
the helium percentage, labeled He%  
the set oxygen partial pressure limit, labeled PO2  
the current oxygen toxicity exposure, labeled OLF  
maximum depth  
current time  
water temperature  
dive time  
tank pressure  
DOWN BUTTON  
TOGGLES  
BETWEEN O2:HE,  
MAXIMUM DEPTH  
TANK PRESSURE  
AND CURRENT  
TIME.  
UP BUTTON  
TOGGLES  
BETWEEN PO2,  
OLF, DIVE TIME  
AND WATER  
TEMPERATURE.  
6.2.3. Oxygen limit fraction (OLF)  
If set to MIXED GAS mode, in addition to tracking the diver's exposure to inert gas, the  
instrument tracks the exposure to oxygen. These calculations are treated as entirely sep-  
arate functions.  
The dive computer calculates separately for Central Nervous System oxygen toxicity (CNS)  
and Pulmonary Oxygen toxicity, the latter measured by the addition of Oxygen Toxicity  
Units (OTU). Both fractions are scaled so that the maximum tolerated exposure for each  
is expressed as 100%.  
The Oxygen Limit Fraction (OLF) displays only the value of the higher of the two calcula-  
tions. The oxygen toxicity calculations are based on the factors listed in Section 10.3.  
Oxygen exposure .  
6.2.4. Gas change and multiple breathing gas mixes  
The Suunto HelO2 allows gas changes to enabled gas mixes during the dive.When the  
maximum operating depth allows for a gas change, the dive computer prompts you to  
change the gas. When PO2 permits better decompression gas to be used, the dive computer  
prompts it automatically if it is set as primary. Gas changes are made by following the  
procedure below:  
32  
 
   
CHANGING GAS MIX. SCROLL  
THROUGH ENABLED MIXES BY  
PRESSING THE UP OR DOWN  
BUTTONS. SELECT NEW MIX BY  
PRESSING THE SELECT BUTTON.  
Mix number, O2%, He% and PO2 for the mixes are shown when  
scrolling. If the set PO2 limit is exceeded , it will be shown with the  
PO2 value blinking. The dive computer does not allow you to change  
to a gas whose set PO2 is exceeded. In such a case, the mix is shown  
but cannot be selected. If the PO2 is less than 0.18 bar, the dive  
computer gives an alarm.  
NOTE  
NOTE  
If no button is pressed in 15 seconds, the dive computer will go back  
to the dive display without changing the gas mix. Upon ascent, the  
computer prompts you to change gas when the PO2 level you have  
set for the next mix allows a gas change. The prompt is an audible 3  
beeps and the current O2 or O2: He mix starts to blink.  
6.3. Diving in GAUGE mode  
If set to GAUGE mode, the dive computer can be used as a bottom timer.  
In the GAUGE mode, the total dive time is always displayed in minutes in the lower right  
corner. In addition, a Dive Timer in the center window displays time in minutes and seconds.  
The center window Dive Timer is activated at the start of the dive and it can be reset during  
the dive and used as a stopwatch by pressing the SELECT button.  
BY PRESSING THE SELECT BUTTON DURING A DIVE, A BOOKMARK  
IS WRITTEN IN THE PROFILE MEMORY, THE DIVE TIMER IS RESET,  
AND THE PREVIOUSLY-TIMED INTERVAL IS DISPLAYED BELOW.  
Tank pressure (if enabled) is also displayed during the dive.  
The GAUGE mode does not provide decompression information.  
NOTE  
NOTE  
If you dive with the GAUGE mode, it is not possible to change between  
the modes before the no fly time (48 h) has counted down.  
33  
 
 
7. AFTER DIVING  
Once back at the surface, Suunto HelO2 continues to provide post-dive safety information  
and alarms. Calculations to enable repetitive dive planning also help to maximize diver  
safety.  
Table 7.1. Alarms  
Symbol on display  
Indication  
Diver Attention Symbol - Extend Surface Interval  
Violated Decompression Ceiling or Too Long Bottom Time  
Do Not Fly Symbol  
7.1. Surface interval  
An ascent to any depth shallower than 1.2 m/4 ft will cause the DIVING display to be re-  
placed by the SURFACE display:  
IT IS 15 MINUTES SINCE YOU SURFACED  
FROM A 6-MINUTE DIVE. THE PRESENT DEPTH IS  
0.0 M. THE AIRPLANE SYMBOL AND NO-FLY VALUE  
INDICATE THAT YOU SHOULD NOT FLY FOR 20  
HOURS.  
Or, in the alternative displays, the following information will be shown:  
maximum depth of last dive in meters/feet  
dive time of last dive in minutes, shown as DIVE TIME  
the current time, shown as TIME  
the current temperature in °C/°F  
If set to MIXED GAS mode, the following information will also be shown:  
the oxygen percentage labeled O2%  
the helium percentage labeled He%  
the oxygen partial pressure labeled PO2  
the current oxygen toxicity exposure labeled OLF  
7.2. Dive numbering  
Several repetitive dives are considered to belong to the same repetitive dive series when  
the dive computer has not counted the no-fly time to zero. Within each series, the dives  
are given individual numbers. The first dive of the series will be numbered as DIVE 1, the  
second as DIVE 2, the third as DIVE 3, etc.  
If you start a new dive with less than 5 minutes of surface interval time, the dive computer  
interprets this as a continuation of the previous dive and the dives are considered to be  
the same. The diving display will return, the dive number will remain unchanged, and the  
dive time will begin where it left off. After 5 minutes on the surface, subsequent dives are,  
by definition, repetitive. The dive counter displayed in the Planning mode will increment  
to the next number if another dive is made.  
34  
 
     
7.3. Repetitive dive planning  
The Suunto HelO2 includes a dive planner that allows you to review the no-decompression  
limits on a subsequent dive, taking the residual nitrogen loading of previous dives into  
consideration. The dive plan mode is not meant for technical dive planning which the  
Suunto Dive Planner PC software is meant for. However, the dive plan mode can be used  
to plan short recreational dives.  
The PC software takes the residual inert gas of the previous dives into consideration when  
the dive profile is downloaded from the dive computer. It is also possible to check how the  
planned air consumption corresponded to the actual air consumption. The Dive Planning  
7.4. Flying after diving  
In DIVE mode, the no-fly time is shown in the center window next to the airplane image.  
In TIME mode, the airplane image is shown in the top left corner.The no-fly time and the  
surface time are shown in TIME mode as well. Flying or traveling to a higher altitude should  
be avoided at any time when the computer is counting down the no-fly time.  
The no-fly time is always at least 12 hours, or equivalent to the so-called desaturation time  
(if longer than 12 hours). For desaturation times lower than 70 minutes, no no-fly time is  
given.  
In the Permanent Error mode and GAUGE mode, the no-fly time is 48 hours.  
The Divers Alert Network (DAN) recommends the following on no-fly times:  
A minimum surface interval of 12 hours would be required in order to be reasonably  
assured a diver will remain symptom free upon ascent to altitude in a commercial jetliner  
(altitude up to 2,400 m/8,000 ft)  
Divers who plan to make daily, multiple dives for several days, or make dives that require  
decompression stops, should take special precautions and wait for an extended interval  
beyond 12 hours before a flight. Further, the Undersea and Hyperbaric Medical Society  
(UHMS) suggests divers using standard air cylinders and exhibiting no symptoms of  
decompression illness wait 24 hours after their last dive to fly in an aircraft with cabin  
pressure up to 2,400 m/8,000 ft. The only two exceptions to this recommendation are:  
If a diver has less than 2 hours total accumulated dive time in the last 48 hours, a  
12 hour surface interval before flying is recommended  
Following any dive that required a decompression stop, flying should be delayed  
for at least 24 hours, and if possible, for 48 hours  
Suunto recommends that flying is avoided until all the DAN and UHMS guidelines, as  
well as the dive computer’s no-fly conditions, are satisfied  
7.5. PLAN mode  
The PLAN mode includes a dive planner (PLANnodec).  
7.5.1. Dive Planning mode (PLANnodec)  
The Dive Planning mode displays no-decompression times for a new dive, taking into ac-  
count the effects of previous dives. No-decompression times are calculated by using the  
bottom gas.  
When entering the PLANnodec mode, the display first briefly shows the remaining desat-  
uration time and no-decompression time at the depth of 9 m/30 ft before going into plan  
mode.  
35  
 
       
By pressing the UP/DOWN buttons, you can scroll the no-decompression limits in 3 m/10  
ft increments ending at 45 m/150 ft. No-decompression limits longer than 99min are dis-  
played as “—“.  
WHEN ENTERING THE PLANNODEC MODE THE DISPLAY FIRST BRIEFLY  
SHOWS THE REMAINING DESATURATION TIME BEFORE GOING INTO PLAN MODE. USE UP  
AND DOWN BUTTONS TO SCROLL DIFFERENT NO-DECOMPRESSION LIMITS.  
NO-DECOMPRESSION LIMITS LONGER THAN 99 MINUTES ARE DISPLAYED AS “–”.  
The Planning mode takes into account the following information from previous dives:  
any calculated residual inert gas  
all dive history for the past four days  
The no-decompression times given for different depths will therefore be shorter than before  
your first “fresh” dive.  
You can exit the planning mode by pressing the MODE button.  
The Planning mode is disabled in GAUGE mode and in Error mode  
(see Section 5.7. Error conditions). The planning mode calculates no-  
decompression times for MIX1 only. If an additional mix is enabled  
in the MIXED GAS mode, it does not affect the calculations in  
PLANNoDec mode.  
NOTE  
Higher Altitude and conservative Personal Adjustment settings will shorten the no-decom-  
pression time limits. These limits at different Altitude and Personal Adjustment setting  
selections are explained in Section 5.10.4. Diving at altitude and in Section 5.10.5. Personal  
adjustments  
Dive numbering shown during dive planning  
Dives belong to the same repetitive dive series if the instrument was still counting down  
the no-fly time at the beginning of the dive.  
The surface interval must be at least 5 minutes for a dive to be considered a repetitive  
dive. Otherwise, it is considered a continuation of the same dive. The dive number will not  
change and the dive time will continue where it left off. (See also Section 7.2. Dive num-  
bering ).  
7.6. MEMORY mode  
The memory options include a dive logbook (MEMLogbook) and dive history (MEMHistory).  
36  
 
 
The dive time and date are registered in the Logbook memory. Always check before diving  
that the time and date are correctly set, especially after traveling between different time  
zones.  
7.6.1. Dive logbook (MEMLogbook)  
The Suunto HelO2 has a very sophisticated, high capacity Logbook and Profile Memory.  
The data is recorded in the profile memory based on the selected sample rate.  
The END OF LOGS text is displayed between the oldest and most recent dive. The following  
information will be shown on three pages:  
THERE ARE THREE PAGES OF LOGBOOK DIVE  
INFORMATION. USE SELECT BUTTON TO SCROLL  
BETWEEN LOGBOOK PAGES I, II,AND III. THE DATA OF  
THE MOST RECENT DIVE IS SHOWN FIRST.  
Page I, main display  
maximum depth  
date of dive  
type of dive (MIXED GAS, GAUGE)  
dive start time  
dive number  
oxygen percentage for Mix used in the beginning of the dive  
helium percentage for Mix used in the beginning of the dive  
dive time  
Page II  
maximum depth  
surface time after previous dive  
average depth  
warnings  
consumed tank pressure  
37  
 
 
OLF percentage of MIXED GAS dive  
Page III  
scrolling  
dive profile (temperature, depth, tank pressure, gases)  
The memory will retain approximately the last 42 hours of dive time.  
After that, when new dives are added, the oldest dives are deleted.  
The contents of the memory will remain when the battery is changed  
(providing that the battery has been replaced according to the instruc-  
tions).  
NOTE  
Several repetitive dives are considered to belong to the same repetitive  
dive series if the no-fly time has not ended. See Section 7.2. Dive  
numbering for further information.  
NOTE  
7.6.2. Dive history  
The dive history is a summary of all the dives recorded by the dive computer.  
DIVE HISTORY DISPLAY.  
TOTAL NUMBER OF DIVES, DIVE  
HOURS AND MAXIMUM DEPTH.  
7.7. Suunto Dive Planner (SDP)  
Suunto Dive Planner is an essential part of your dive. It is used for creating dive plans.  
Using the Suunto Dive Planner software is not a substitute for proper  
dive training. Diving with mixed gases has dangers that are not famil-  
iar to divers diving with air. To dive with trimix, triox, heliox and nitrox  
or all of them, divers must have specialized training for the type of  
diving they are doing.  
WARNING  
Start creating a dive plan by defining the maximum depth and bottom time. Next, plan  
travel, bottom and decompression gases. Based on the gases, the Dive Planner calculates  
the decompression schedule, gas change and decompression depths. After the decom-  
pression schedule is ready, the needed gas volume for the dive is calculated based on  
the Surface Air Consumption (SAC) rate that can be checked from Suunto Dive Manager.  
Always use realistic SAC rates and conservative turn pressures during  
dive planning. An over-optimistic or erroneous gas planning can result  
in the exhaustion of breathing gas during decompression or in a cave  
or a wreck.  
WARNING  
After you finish planning your dive with Suunto Dive Planner, download the gases, settings  
and alarms into your dive computer. You can use your Suunto HelO2 to fine-tune the set-  
tings and gases manually.  
Always use alternative dive planning methods, such as dive tables, when you plan the  
dive. After planning your dive, analyze your dive gases and if they differ substantially from  
the planned gases, replan your dive. Also check the lost gas scenarios in case your de-  
compression gases are altered during a dive, for example, due to a lost cylinder or a broken  
valve.  
38  
 
   
For emergency ascents, always print out the dive plan from Suunto  
Dive Planner. It ensures that you have a valid decompression  
schedule at hand in an unlikely event that the dive computer malfunc-  
tions.  
NOTE  
For more information about the warnings, such as Isobaric Counterdiffusion (ICD), and  
settings in Suunto Dive Planner, refer to Suunto Dive Planner Help.  
7.8. Suunto Dive Manager (SDM)  
Suunto Dive Manager (SDM) is optional PC software that greatly enhances the function-  
ality of your Suunto HelO2.  
With the SDM software, you can download dive data from your dive computer to your PC.  
You can then view and organize all the data recorded with your Suunto HelO2. You can  
also transfer dive profiles to Suunto Dive Planner, print copies of your dive profiles and  
upload your dive logs to share with your friends at SuuntoSports.com.  
Please check for updates regularly as new features are constantly being developed.  
The following data is transferred to your PC:  
depth profile of the dive  
dive time  
preceding surface interval time  
dive number  
dive start time (year, month, day and time)  
dive computer settings  
oxygen and helium percentage settings and maximum OLF (in MIXED GASmode)  
tissue calculation data  
real-time water temperature  
real-time tank pressure (with optional wireless transmitter in use)  
additional dive information (e.g. SLOW and Mandatory Safety Stop violations, Diver  
Attention Symbol, Bookmark, Surfaced Mark, Decompression Stop Mark, Ceiling Error  
Mark)  
dive computer serial number  
personal information (30 characters)  
tank pressure consumption (with optional wireless transmitter in use)  
Using SDM, you are able to enter setup options such as:  
input a personal, 30-character field into the Suunto HelO2  
reset the Dive History’s maximum depth to zero  
It is also possible to manually add comments, multimedia and other personal information  
to the PC-based dive data files.  
When you have dived and transferred your dive data to your Suunto Dive Manager, you  
can share your best experiences with other diving enthusiasts at SuuntoSports.com. It's  
a free and open Internet community where you can compare your underwater experiences  
with other Suunto users and learn from each other.  
SuuntoSports.com includes three sections.  
In My Suunto you can register your dive computer and manage your membership profile.  
The section also contains a personal event calendar.  
39  
 
   
The Communities section is meeting a place for smaller groups of SuuntoSports.com  
members. Here you can create and manage your own communities and search for others.  
All communities have a home page that lists the latest group activities. Community members  
can also use group-specific bulletin boards and calendars, create their own link lists and  
group activities. All registered SuuntoSports.com users automatically become members  
of the ‘World of Suunto Sports’ community.  
The Sport forums include sport-specific news, bulletin boards, event calendars, ranking  
lists and discussions. You can also exchange experiences and read travel reports written  
by other members.  
To learn more about SuuntoSports.com’s functions and activities, visit the site, try them  
and, if necessary, use the site Help. The Help is available on the right side of the bar that  
divides the screen.  
40  
 
8. CARE AND MAINTENANCE OF MY SUUNTO DIVING COMPUTER  
The SUUNTO dive computer is a sophisticated precision instrument. Although it is designed  
to withstand the rigors of scuba diving, you must treat it with the same proper care and  
caution as any other precision instrument.  
WATER CONTACTS AND PUSH BUTTONS  
Contamination or dirt on the water contacts/connector or push buttons may prevent  
the automatic activation of the Dive Mode and cause problems during the data transfer.  
Therefore, it is important that the water contacts and push buttons are kept clean. If  
the water contacts are active (AC text remains on display) or the Dive Mode activates  
on its own, the reason for this is probably contamination or invisible marine growth,  
which may create an electric current between the contacts. It is important that the dive  
computer is carefully washed in fresh water after the day’s diving is completed. The  
contacts can be cleaned with fresh water and, if necessary, a mild detergent and a soft  
brush. Sometimes it might be necessary to remove the instrument from the protective  
boot for cleaning.  
CARE OF YOUR DIVE COMPUTER  
NEVER try to open the case of the dive computer.  
Have your dive computer serviced every two years or after 200 dives (whichever  
comes first) by an authorized dealer or distributor. This service will include a general  
operational check, replacement of the battery, and water resistance check. The  
service requires special tools and training. Therefore, it is advisable to contact an  
authorized SUUNTO dealer or distributor for the biennial service. Do not attempt  
to do any servicing that you are not sure of.  
Should moisture appear inside the case, immediately have the instrument checked  
by your SUUNTO dealer or distributor.  
Should you detect scratches, cracks or other such flaws on the display that may  
impair its durability, immediately have it replaced by your SUUNTO dealer or dis-  
tributor.  
Wash and rinse the unit in fresh water after every use.  
Protect the unit from shock, extreme heat, direct sunlight, and chemical attack. The  
dive computer cannot withstand the impact of heavy objects like scuba cylinders,  
nor chemicals like gasoline, cleaning solvents, aerosol sprays, adhesive agents,  
paint, acetone, alcohol, etc. Chemical reactions with such agents will damage the  
seals, case and finish.  
Store your dive computer in a dry place when you are not using it.  
The dive computer will display a battery symbol as a warning when the power gets  
too low. When this happens, the instrument should not be used until the battery  
has been replaced.  
Do not fasten the strap of your dive computer too tightly. You should be able to insert  
your finger between the strap and your wrist. Shorten the strap by cutting it if you  
do not expect to need the extra length.  
MAINTENANCE  
The instrument should be soaked, thoroughly rinsed with fresh water, then dried with  
a soft towel after each dive. Make sure that all salt crystals and sand particles have  
been flushed out. Check the display for possible moisture or water. DO NOT use the  
dive computer if you detect any moisture or water inside. Contact an authorized Suunto  
dealer for battery replacement or other service.  
CAUTION!  
Do not use compressed air to blow water off the unit.  
Do not use solvents or other cleaning fluids that might cause damage.  
Do not test or use the dive computer in pressurized air.  
WATER RESISTANCE INSPECTION  
41  
 
 
The water resistance of the unit must be checked after replacing the battery or after  
other service operations. The check requires special equipment and training. You must  
frequently check the display for any sign of leaks. If you find moisture inside your dive  
computer, there is a leak. A leak must be corrected without delay as moisture will ser-  
iously damage the unit, even beyond repair. SUUNTO does not take any responsibility  
for damage caused by moisture in the dive computer unless the instructions of this  
manual are carefully followed. In the event of a leak, immediately take the dive computer  
to an authorized SUUNTO dealer or distributor.  
FAQs  
WHAT CAN I DO TO MY SUUNTO DIVING COMPUTER MYSELF?  
It is advisable to contact an authorized Suunto service, distributor or  
NOTE  
retailer for any repairs. Batteries and straps can be replaced by the  
user when the change is made in a proper manner to avoid any  
leakage of water into the battery compartment or computer. Original  
battery replacement and strap kits must be used.  
Batteries can be changed by the user in all diving computers except Stinger, D4, D6 and  
D9.  
Instructions for changing batteries and straps can be found in the user manuals or at  
WHAT ARE ORIGINAL SUUNTO ACCESSORIES?  
Original Suunto accessories are only distributed through Suunto`s worldwide network of  
authorized Suunto distributors and retailers.  
Original Suunto accessories are tested to be compatible with Suunto products and can  
be used safely.  
Damage caused by non-original accessories will not be covered by  
warranty.  
NOTE  
HOW TO GET MORE INFORMATION  
You can find service & warranty information in these pages by searching the FAQs.  
If you do not find the answer in the FAQs, you can also send a support request. To be  
able to send a support request you have to register in the system. REGISTER NOW.  
You can also contact our European help desk by telephone at +358 2 284 1160. The cost  
of the call is that of a normal call to Finland. The call center is open Mon-Fri, 24h/day. The  
service is provided in English all the time. Other languages - French, German, Swedish,  
Japanese, Spanish and Finnish – are only provided during local business hours. Call  
center professionals can answer customer questions regarding diving products, outdoor  
products and compasses.  
HOW DO I KNOW IF MY SUUNTO PRODUCT IS COVERED BY WARRANTY?  
You can check the proof pf purchase, which has to be 2 years or less. You can also check  
the serial number of your unit.  
Does repairing my Suunto product extend the warranty?  
As far as the national laws permit, repairing the product does not extend or otherwise affect  
the warranty period. However, part(s) repaired or replacement product(s) provided during  
the warranty period will be warranted for the remainder of the original warranty period or  
for three (3) months from the date of repair or replacement, whichever is longer.  
42  
 
9. BATTERY REPLACEMENT  
It is advisable to contact an authorized Suunto representative for  
NOTE  
battery replacement. It is imperative that the change is made in a  
proper manner to avoid any leakage of water into the battery compart-  
ment or computer.  
Defects caused by improper battery installation are not covered by  
the warranty.  
CAUTION  
CAUTION  
When the battery is changed, all nitrogen and oxygen uptake data is  
lost. Therefore, the no-fly time shown by the computer should have  
reached zero or you must wait for 48 hours, or preferably up to 100  
hours, before you dive again.  
All history and profile data, as well as the altitude, personal, and alarm settings, will remain  
in the dive computer memory after the battery change. However, the clock time and time  
alarm settings are lost. In the MIXED GAS mode, the gas mix settings also revert back to  
default settings (MIX1 21% O2, 0% He, 1.4 bar PO2).  
9.1. Battery kit  
The battery kit includes a 3.0 V coin type lithium cell battery and a lubricated O ring. When  
handling the battery do not make contact with both of the poles at the same time. Do not  
touch the surfaces of the battery with your bare fingers.  
9.2. Required tools  
A flat 1.5 mm screwdriver or a special tool for spring bars (K5857).  
Soft cloth for cleaning.  
Needlenose pliers or small screwdriver for turning securing ring.  
9.3. Replacing the battery  
The battery and the buzzer are located in the back of the instrument in a separate com-  
partment. To change the battery:  
Thoroughly rinse and dry the computer.  
1.  
2.  
Open the securing ring of the battery compartment lid by pushing it down and rotating  
it clockwise. You may use a pointed nose pliers or a small screwdriver as an aid in  
the rotating. Put the pliers ends into the holes of the securing ring or the screwdriver  
onto the side of the right tooth on the ring and turn the ring clockwise. Be careful not  
to damage any of the parts.  
Remove the ring.  
3.  
4.  
Carefully remove the lid with the beeper attached to it. You can remove the lid by  
pressing with your finger on the outermost edge of the lid while simultaneously pulling  
with your nail at the opposite side. Don't use sharp metal objects as they might damage  
the O-ring or the sealing surfaces.  
Remove the O-ring and the battery retainer.  
Carefully remove the battery. Do not damage the electrical contacts or the sealing  
surface.  
5.  
6.  
Check for any traces of flooding, particularly between the beeper and the lid, or for  
any other damage. In case of a leak or any other damage, bring the dive computer  
to an authorized SUUNTO dealer or distributor for check and repair.  
Check the condition of the O-ring; a defective O-ring may indicate sealing or other  
problems. Dispose the old O-ring, even if it seems to be in good condition.  
Check that the battery compartment, battery holder and lid are clean. Clean with soft  
cloth if necessary.  
7.  
8.  
9.  
Reinstall the battery retainer in its correct position.  
10.  
43  
 
       
Check that the new lubricated O-ring is in good condition. Put it in the right position  
on the battery compartment lid. Be very careful not to get any dirt on the o-ring or its  
sealing surfaces.  
11.  
Carefully press the lid onto the battery compartment with your thumb, while making  
sure that the O-ring is not at any point protruding out on the edge.  
Put your other thumb through the locking ring. Press this thumb firmly against the lid  
and release the other one. Make sure that the lid is pressed completely down!  
Turn the locking ring counterclockwise with your free thumb and fingers until it snaps  
into its locked position.  
12.  
13.  
14.  
15.  
The dive computer should now active its timekeeping mode and show time 18:00  
[6:00 PM] and date SA 01,01. Activate the instrument. Check that  
all display segments work.  
the low battery warning is off.  
the buzzer beeps and backlight works.  
all the settings are correct. Reset if necessary.  
Check after the first dives for possible moisture under the transparent  
battery compartment lid, indicating a leak.  
CAUTION  
Securing Ring  
HelO2  
Battery Compartment  
Lid with buzzer  
Battery  
O-Ring  
Battery Retainer  
9.4. Wireless transmitter battery replacement  
It is advisable to contact an authorized Suunto representative for  
transmitter battery replacement. It is imperative that the change is  
made in a proper manner to avoid any leakage of water into the  
transmitter.  
NOTE  
44  
 
 
Defects caused by improper battery installation are not covered by  
the warranty.  
CAUTION  
9.4.1. Transmitter battery kit  
The transmitter battery kit includes a 3.0 V CR ½ AA lithium cell battery and a lubricated  
O-ring. When handling the battery, do not make contact with both of the poles at the same  
time. Do not touch the metal surfaces of the battery with your bare fingers.  
9.4.2. Required tools  
A Phillips-head screwdriver  
Soft cloth for cleaning  
9.4.3. Replacing the transmitter battery  
To change the transmitter battery:  
Remove the transmitter from the regulator HP port.  
Unscrew and remove the four Phillips screws on the back of the transmitter.  
Pull off the transmitter cover.  
Carefully remove the o-ring. Be careful not to damage the sealing surfaces.  
Carefully remove the battery. Do not touch the electrical contacts or the circuit board.  
1.  
2.  
3.  
4.  
5.  
Check for any traces of leakage, or for any other damage. If there is a leak or any  
other damage, take the transmitter to an authorized Suunto representative or distrib-  
utor for checking and repair.  
Check the condition of the O-ring. A defective O-ring may indicate sealing or other  
problems. Dispose of the old O-ring, even if it seems to be in good condition  
Check that the O-ring groove and the sealing surface of the cover are clean. Clean  
them with a soft cloth if necessary.  
Gently insert the new battery into the battery compartment. Check the polarity of the  
battery. The "+" mark should point toward the top of the compartment and the "-" mark  
towards the bottom.  
6.  
7.  
8.  
It is imperative that you wait at least 30 seconds before re-in-  
stalling the transmitter battery.  
NOTE  
When the battery is re-installed, the transmitter sends an overpressure (“---“) signal  
on code 12 for 10 seconds, after which it goes to normal operation, and shuts down  
after 5 minutes.  
Check that the new lubricated O-ring is in good condition. Put it in the right position  
in the O-ring groove. Be very careful not to get any dirt on the O-ring or its sealing  
surfaces.  
9.  
Carefully put the transmitter cover into place. Note that the cover will only fit in one  
position. Match the three slots on the inside of the cover with the three ledges below  
the battery.  
10.  
11.  
Screw the four screws back into place.  
45  
 
     
Wireless transmitter parts. The code stands for spare part order number.  
46  
 
10. TECHNICAL DATA  
10.1. Technical specifications  
Dimensions and weight:  
Diameter: 61.0 mm/2.4 in  
Thickness: 28 mm/1.1 in  
Weight: 68 g/2.4 oz  
Transmitter:  
Max. diameter: 40 mm/1.57 in  
Length: 80 mm/3.15 in  
Weight: 118 g/4.16 oz  
Rated working pressure: 300 bar/4000 psi, maximum allowed pressure 360 bar/5,000  
psi  
Display resolution: 1 bar/1 psi  
Depth gauge:  
Temperature compensated pressure sensor  
Fresh water calibrated (calibrated in compliance with EN 13319)  
Maximum depth of operation: 120 m/393 ft (complying with EN 13319)  
Accuracy: ± 1% of full scale or better from 0 to 120 m/394 ft at 20°C/68°F (complying  
with EN 13319)  
Depth display range: 0 to 150 m/492 ft  
Resolution: 0.1 m from 0 to 100 m, 1 m from 100 to 150 m/1 ft from 0 to 492 ft  
Temperature display:  
Resolution: 1°C/1°F  
Display range: -20 to +50°C/-9 to +122°F  
Accuracy: ± 2°C/± 3.6°F within 20 minutes of temperature change  
Calendar clock:  
Accuracy: ± 25 s/month (at 20°C/68°F)  
12/24 h display  
Displays only in MIXED GAS mode:  
Oxygen %: 8 - 99  
Helium %: 0 – 92  
Oxygen partial pressure display: 0.0 – 3.0 bar.  
Oxygen Limit Fraction: 0 - 200% with 1% resolution  
Logbook/dive profile memory:  
Recording interval: 20 seconds adjustable (10,20,30,60s).  
Memory capacity: approximately 80 hours of diving with 20 second recording interval  
Depth resolution: 0.3 m/1 ft  
Operating conditions:  
Operating altitude range: 0 to 3,000 m/10,000 ft above sea level  
Operating temperature: 0°C to 40°C/32°F to 104°F  
Storage temperature: -20°C to +50°C/ -4°F to +122°F  
It is recommended that the instrument be stored in a dry place at room temperature.  
Do not leave the dive computer in direct sunlight!  
Tissue calculation model:  
NOTE  
Suunto Technical RGBM algorithm (developed by Suunto and Bruce R. Wienke, BSc,  
MSc, PhD)  
9 tissue compartments  
Tissue compartment halftimes: 2.5, 5, 10, 20, 40, 80, 120, 240 and 480 minutes (on  
gassing). The off gassing halftimes are slowed down  
47  
 
   
Helium halftimes:1, 2, 3.5, 7.5, 15, 30, 45, 90, 181 minutes (on gassing). The off  
gassing halftimes are slowed down.  
Reduced gradient (variable) "M" values based on diving habit and dive violations. The  
"M" values are tracked up to 100 hours after a dive  
The EAN and oxygen exposure calculations are based on recommendations by R.W.  
Hamilton, PhD and currently accepted exposure time limit tables and principles  
Battery:  
One 3 V lithium battery: CR 2450  
Battery storage time (shelf life): Up to three years  
Replacement: Every three years, or more often depending on dive activity  
Life expectancy at 20°C/68°F:  
100 dives/year –>1 year  
Transmitter:  
One 3V lithium battery: 1/2AA (K5546) and O-ring 2.00 mm x 2.00 mm (K5538)  
Battery storage time (shelf life): Up to three years  
Replacement: Every two years, or more often depending on dive activity  
Life expectancy at 20°C/68°F:  
0 dives/year –> 3 years  
100 dives/year –> 2 years  
400 dives/year –> 1 year  
The following conditions have an effect on the expected battery lifetime:  
The length of the dives  
The conditions in which the unit is operated and stored (e.g. temperature/cold condi-  
tions). Below 10°C/50°F the expected battery lifetime is about 50-75% of that at  
20°C/68°F  
The use of the backlight and audible alarms  
The quality of the battery. (Some lithium batteries may exhaust unexpectedly, which  
cannot be tested in advance)  
The time the dive computer has been stored until it gets to the customer. (The battery  
is installed in the unit at the factory)  
Low temperature or an internal oxidation of the battery may activate  
the battery warning even though the battery has enough capacity. In  
this case, the warning usually disappears when the DIVE mode is  
activated again.  
NOTE  
10.2. RGBM  
The Suunto Reduced Gradient Bubble Model (RGBM) is a modern algorithm for predicting  
both dissolved and free gas in the tissues and blood of divers. It was developed in co-op-  
eration between Suunto and Bruce R. Wienke BSc, MSc, PhD. It is based on both labor-  
atory experiments and diving data, including data from DAN.  
It is a significant advance on the classical Haldane models, which do not predict free gas  
(microbubbles). The advantage of Suunto RGBM is additional safety through its ability to  
adapt to a wide variety of situations. Suunto RGBM addresses a number of diving circum-  
stances outside the range of dissolved-gas-only models by:  
Monitoring continuous multiday diving  
Computing closely spaced repetitive diving  
Reacting to a dive deeper than the previous dive  
Adapting to rapid ascents which produce high microbubble (silent-bubble) build-up  
Incorporating consistency with real physical laws for gas kinetics  
48  
 
 
10.2.1. Suunto Technical RGBM decompression model  
Suunto's decompression model development originates from the 1980s when Suunto im-  
plemented Bühlmann's model based on M-values in Suunto SME. Since then research  
and development has been ongoing with the help of external and internal experts. In the  
late 1990s Suunto implemented Dr. Bruce Wienke's RGBM bubble model to work with the  
M model. The first commercial products with the feature were Vyper and Stinger. With  
these products the improvement of diver safety was significant.  
Now Suunto has taken another leap in decompression modeling by introducing Suunto  
Technical RGBM decompression model with He tissues.  
Suunto Technical RGBM model is a modified version of the M-value model. Calculation  
of the M-value model can be found in common dive literature. Modifications have been  
made to have the model follow RGBM theory as closely as possible. The modifications  
have been conducted with the help of Dr. Bruce Wienke. Functionality of Suunto Technical  
RGBM has been validated and verified to the depth of 120 m/393 ft with hundreds of test  
dives both in the field and in laboratory. The algorithm should not be used in deeper depths  
than the verified depth.  
Suunto technical algorithm models the human body by using nine tissue groups. In theory  
the model is accurate if there are more tissue groups, but using more than nine tissue  
groups has no practical significance.  
Tissue calculation aims to model the amount of nitrogen (N2) and helium (He) saturated  
in tissues. Ongasing and offgasing of saturated gas is modelled using the ideal gas  
equation. In practice this means that the total pressure of the nitrogen and helium tissues  
can be higher than the total pressure of the breathing gas, even without any exposure to  
pressure. For example, when a diver dives an air dive soon after a demanding trimix dive,  
the residual pressure of helium combined with a high nitrogen content cause the diver a  
decompression obligation very fast.  
10.2.2. Diver safety and Suunto Technical RGBM model  
Because any decompression model is purely theoretical and does not monitor the actual  
body of a diver, no decompression model can guarantee the absence of DCI. Suunto  
Technical RGBM model has many features that reduce the risk of DCI. The Suunto  
Technical RGBM algorithm adapts its predictions of both the effects of microbubble build-  
up and adverse dive profiles in the current dive series. The pattern and speed of decom-  
pression is adjusted according to the microbubble influence. The adjustment is also applied  
to the maximum combined nitrogen and helium overpressure in each theoretical tissue  
group. To add diver safety, offgasing is also slowed down compared to ongasing and the  
amount of slowing down depends on the tissue group.  
Experimentally it has been shown that the body adapts to decompression to some degree  
when diving is constant and frequent. Two personal adjustment settings (P-1 and P-2) are  
available for divers who dive constantly and are ready to accept greater personal risk.  
Always use the same personal and altitude adjustment settings for  
the actual dive than for the planning. Increasing the personal adjust-  
ment setting from the planned setting as well as increasing the altitude  
adjustment setting can lead to longer decompression times deeper  
and thus to larger required gas volume. You can run out of breathing  
gas underwater if the personal adjustment setting has been changed  
after dive planning.  
CAUTION  
49  
 
   
10.2.3. Altitude diving  
The atmospheric pressure is lower at high altitudes than at sea level. After traveling to a  
higher altitude, you will have additional nitrogen in your body, compared to the equilibrium  
situation at the original altitude. This "additional" nitrogen is released gradually over time  
and equilibrium is restored. It is recommended that you acclimatize to a new altitude by  
waiting at least three hours before making a dive.  
Before high-altitude diving, the instrument must be set to the Altitude Adjustment mode  
to adjust the calculations for the new altitude. The maximum partial pressures of nitrogen  
allowed by the mathematical model of the dive computer are reduced according to the  
lower ambient pressure.  
As a result, the allowed no-decompression-stop limits are considerably reduced.  
10.3. Oxygen exposure  
The oxygen exposure calculations are based on currently accepted exposure time limit  
tables and principles. In addition to this, the dive computer uses several methods to con-  
servatively estimate the oxygen exposure. For example:  
the displayed oxygen exposure calculations are raised to the next higher percentage  
value  
for recreational scuba diving, the recommended upper limit of 1.4 bar PO2 is used as  
a default  
the CNS % limits up to 1.6 bar are based on 1991 NOAA Diving Manual limits  
the OTU monitoring is based on the long-term daily tolerance level and the recovery  
rate is reduced  
Oxygen related information displayed by the dive computer is also designed to ensure  
that all warnings and displays occur at the appropriate phases of a dive. For example, the  
following information will be shown before and during a dive when the computer is set in  
mode:  
the selected O2% on the alternative display  
OLF% alternative display for either CNS% or OTU% (whichever is larger)  
audible alarms are given and the OLF value starts to blink when the 80% and 100%  
limits are exceeded  
audible alarms are given and the actual PO2 value blinks when it exceeds the preset  
limit  
in dive planning, the maximum depth according to the O2% and maximum PO2 selected  
50  
 
   
11. INTELLECTUAL PROPERTY  
11.1. Copyright  
This user's manual is copyrighted and all rights are reserved. It may not, in whole or in  
part, be copied, photocopied, reproduced, or translated to any media without prior written  
consent from Suunto.  
11.2. Trademark  
Suunto, HelO2, Consumed Bottom Time (CBT), Oxygen Limit Fraction (OLF), Suunto  
Reduced Gradient Bubble Model (RGBM), and Continuous Decompression and their logos  
are all registered or unregistered trademarks of Suunto. All rights are reserved.  
11.3. Patent notice  
This product is protected by the following patents and patent applications: US 5,845,235  
and US11/152,075. Other patents have been applied for.  
51  
 
       
12. DISCLAIMERS  
12.1. User’s responsibility  
This instrument is intended for recreational use only. Suunto HelO2 must not be used for  
obtaining measurements that require professional or industrial precision.  
12.2. CE  
The CE mark is used to mark conformity with the European Union EMC directive  
89/336/EEC  
FIOH, Topeliuksenkatu 41 a A, FI-00250 Helsinki, Finland, notified body no.0430, has EC  
type-examined this type of personal protective equipment.  
EN 250 Respiratory equipment - Open circuit self-contained compressed air diving appar-  
atus – Requirements, testing, marking.  
EN 13319 ”Diving accessories – Depth gauges and combined depth and time measuring  
devices – Functional and safety requirements, test methods” is a European diving depth  
gauge standard. The Suunto is designed to comply with this standard.  
52  
 
     
13. SUUNTO LIMITED WARRANTY FOR SUUNTO DIVING COM-  
PUTERS AND SUUNTO DIVING COMPUTER ACCESSORIES  
This Limited Warranty is valid as of January 1st, 2007.  
Suunto Oy ("Suunto") provides this limited warranty to those who have purchased the  
Suunto Diving computer and/or Suunto diving computer accessories ("Product").  
Suunto warrants that during the Warranty Period Suunto or a Suunto Authorized Service  
Center will, at its sole discretion, remedy defects in materials or workmanship free of  
charge either by a) repairing the Product or the parts, or b) replacing the Product or the  
parts, or c) refunding the purchase price of the Product, subject to the terms and conditions  
of this Limited Warranty. Your mandatory legal rights under your applicable national laws  
relating to the sale of consumer products are not affected by this Limited Warranty.  
This Limited Warranty is only valid and enforceable in the country in which you purchased  
the Product, provided that Suunto has intended the Product for sale in that country. If,  
however, you purchased the Product in a member state of the European Union, Iceland,  
Norway, Switzerland or Turkey, and Suunto originally intended the Product for sale in one  
of these countries, this Limited Warranty is valid and enforceable in all of these countries.  
The warranty service may be limited due to the possible country-specific elements in the  
Products.  
In countries outside the European Union, Iceland, Norway, Switzerland or Turkey, subject  
to your agreement to pay a service fee and compensation for the possible shipment costs  
incurred by Suunto or a Suunto Authorized Service Centre, you can have warranty service  
other than in the country in which you purchased the Product. Any spare parts will be  
provided free of charge in this case.  
Warranty Period  
The Warranty Period starts at the date of retail purchase by the original end-user purchaser.  
The Product may consist of several different parts, and the different parts may be covered  
by a different warranty period (hereinafter "Warranty Period"). The different Warranty  
Periods are:  
a. Two (2) years for the diving computers;  
b. One (1) year for the consumable parts and accessories, including (but not limited to)  
chargeable batteries, chargers, docking stations, straps, cables and hoses (whether in-  
cluded in the diving computer sales package or sold separately).  
To the extent your national laws permit, the Warranty Period will not be extended or re-  
newed or otherwise affected due to subsequent resale, Suunto authorized repair or re-  
placement of the Product. However, part(s) repaired or replaced during the Warranty  
Period will be warranted for the remainder of the original Warranty Period or for three (3)  
months from the date of repair or replacement, whichever is longer.  
Exclusions and Limitations  
This Limited Warranty does not cover:  
a) normal wear and tear, b) defects caused by rough handling (including, without  
limitation, defects caused by sharp items, by bending, compressing or dropping, etc.),  
or c) defects or damage caused by misuse of the Product, including use that is contrary  
to the instructions provided by Suunto (e.g. as set out in the Product's user guide  
and/instruction manual), and/or e) other acts beyond the reasonable control of Suunto;  
user manuals or any third-party software (even if packed or sold with the Suunto  
hardware), settings, content or data, whether included or downloaded in the Product,  
or whether included during installment, assembly, shipping or at any other time in the  
delivery chain or otherwise and in any way acquired by you;  
1.  
2.  
defects or alleged defects caused by the fact that the Product was used with, or  
connected to, any product, accessory, software and/or service not manufactured or  
supplied by Suunto, or was used otherwise than for its intended use;  
3.  
4.  
replaceable batteries.  
53  
 
 
This Limited Warranty is not enforceable if:  
the Product has been opened, modified or repaired by anyone other than Suunto or  
a Suunto Authorized Service Centre;  
1.  
the Product has been repaired using unauthorized spare parts;  
the Product's serial number has been removed, erased, defaced, altered or made il-  
legible in any way - and this shall be determined at the sole discretion of Suunto;  
the Product has been exposed to influence from chemical products including (but not  
limited to) mosquito repellents.  
2.  
3.  
4.  
Suunto does not warrant that the operation of the Product will be uninterrupted or error  
free, or that the Product will work in combination with any hardware or software provided  
by a third party.  
Access to Suunto warranty service  
tomer service or referred to in the Product manual before seeking warranty service.  
If a claim under this Limited Warranty appears to be necessary, please contact your local  
authorized Suunto retailer – for contact information please visit the Suunto website  
further details on how to make a claim. You will then be advised on how to bring your  
Product for warranty service. Should you wish to return the Product by shipping it to your  
local authorized Suunto retailer, please use prepaid freight. When making a claim under  
this Limited Warranty you are required to include your name and address, proof of purchase  
sidered adequate for this purpose), as required in your country, which clearly indicates  
the serial number, name and address of the seller, the date and place of purchase, and  
the product type. The claim will be honored and the Product repaired or replaced at no  
charge and returned in a reasonable amount of time. This shall be determined at the sole  
discretion of Suunto or a Suunto Authorized Service Center. If the Product is found not to  
be covered by the terms and conditions of this Limited Warranty, Suunto or a Suunto Au-  
thorized Service Centre reserve the right to charge a handling fee.  
Any claim under this Limited Warranty is subject to you notifying Suunto or a Suunto Au-  
thorized Service center of the alleged defect within a reasonable time of it having come  
to your attention, and in any event no later than before the expiry of the Warranty Period.  
Other important notices  
Please remember to take backup copies of all important content and data stored in your  
Product because content and data may be lost during repair or replacement of the Product.  
Suunto or a Suunto Authorized Service Centre is not responsible for any damage or loss  
of any kind whatsoever resulting from loss of, damage to, or corruption of content or data  
during repair or replacement of the Product.  
When the Product or a part is replaced, any replaced item becomes the property of Suunto.  
If a refund is given, the Product for which the refund is given must be returned to a Suunto  
Authorized Service Centre as it becomes the property of Suunto and/or Suunto Authorized  
Service Centre.  
When repairing or replacing the Product, Suunto or a Suunto Authorized Service Centre  
may use products or parts that are new, equivalent to new or re-conditioned.  
Limitation of Liability  
TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE MANDATORY LAWS, THIS  
LIMITED WARRANTY IS YOUR SOLE AND EXCLUSIVE REMEDY AND IS IN LIEU OF  
ALL OTHER WARRANTIES EXPRESSED OR IMPLIED. SUUNTO SHALL NOT BE LIABLE  
FOR SPECIAL, INCIDENTAL, PUNITIVE OR CONSEQUENTIAL DAMAGES, INCLUDING  
BUT NOT LIMITED TO LOSS OF ANTICIPATED BENEFITS OR PROFITS, LOSS OF  
SAVINGS OR REVENUE, LOSS OF DATA, PUNITIVE DAMAGES, LOSS OF USE OF  
THE PRODUCT OR ANY ASSOCIATED EQUIPMENT, COST OF CAPITAL, COST OF  
ANY SUBSTITUTE EQUIPMENT OR FACILITIES, DOWNTIME, THE CLAIMS OF ANY  
THIRD PARTIES, INCLUDING CUSTOMERS, AND INJURY TO PROPERTY RESULTING  
54  
 
FROM THE PURCHASE OR USE OF THE PRODUCT OR ARISING FROM BREACH  
OF THE WARRANTY, BREACH OF CONTRACT, NEGLIGENCE, STRICT TORT, OR  
ANY OTHER LEGAL OR EQUITABLE THEORY, EVEN IF SUUNTO KNEW OF THE  
LIKELIHOOD OF SUCH DAMAGES. SUUNTO SHALL NOT BE LIABLE FOR DELAY IN  
RENDERING SERVICE UNDER THE LIMITED WARRANTY, OR LOSS OF USE DURING  
THE TIME THE PRODUCT IS BEING REPAIRED.  
55  
 
14. DISPOSAL OF THE DEVICE  
Please dispose of the device in an appropriate way, treating it as electronic waste. Do not  
throw it in the garbage. If you wish, you may return the device to your nearest Suunto  
representative.  
56  
 
 
GLOSSARY  
Altitude dive  
Ascent rate  
ASC RATE  
Ascent time  
A dive made at an elevation greater than 300 m/1000 ft above sea level.  
The speed at which the diver ascends toward the surface.  
Abbreviation for ascent rate.  
The minimum amount of time needed to reach the surface on a decompression  
stop dive.  
ASC TIME  
Ceiling  
Abbreviation for ascent time.  
On a decompression stop dive, the shallowest depth to which a diver may as-  
cend based on computed nitrogen load.  
Central nervous system toxicity  
Toxicity caused by oxygen. Can cause a variety of neurological symptoms.  
The most important of which is an epileptic-like convulsion which can cause a  
diver to drown.  
CNS  
Abbreviation for central nervous system toxicity.  
Central nervous system toxicity limit fraction. Also note Oxygen Limit Fraction  
See "Tissue group".  
CNS%  
Compartment  
DAN  
Abbreviation for Divers Alert Network.  
DCI  
Abbreviation for decompression illness.  
Decompression  
Time spent at a decompression stop, or range, before surfacing, to allow ab-  
sorbed nitrogen to escape naturally from tissues  
Decompression range  
Decompression illness  
On a decompression stop dive, the depth range between the floor and the  
ceiling within which a diver must stop for some time during ascent.  
Any of a variety of maladies resulting either directly or indirectly from the  
formation of nitrogen bubbles in tissues or body fluids, as a result of inad-  
equately controlled decompression. Commonly called "the bends" or "DCI".  
Dive series  
Dive time  
A group of repetitive dives between which the dive computer indicates some  
nitrogen loading is present. When nitrogen loading reaches zero the dive  
computer deactivates.  
Elapsed time between leaving the surface to descend, and returning to the  
surface at the end of a dive.  
EAD  
Abbreviation for equivalent air depth.  
Abbreviation for enriched air nitrox.  
EAN  
Enriched air nitrox  
Also called nitrox or Enriched Air = EANx. Air that has some oxygen added.  
Standard mixes are EAN32 (NOAA Nitrox I = NN I) and EAN36 (NOAA Nitrox  
II = NN II).  
Equivalent air depth  
Floor  
Nitrogen partial pressure equivalent table.  
The deepest depth during a decompression stop dive at which decompression  
takes place.  
Half time  
After a change in ambient pressure, the amount of time required for the partial  
pressure of nitrogen in a theoretical compartment to go half way from its previ-  
ous value to saturation at the new ambient pressure.  
He%  
Helium percentage or helium fraction in the breathing gas.  
A breathing gas mix of helium and oxygen.  
Heliox  
Multi level dive  
A single or repetitive dive that includes time spent at various depths and whose  
no decompression limits are therefore not determined solely by the maximum  
depth attained.  
Nitrox  
In sports diving, refers to any mix with a higher fraction of oxygen than standard  
air.  
NOAA  
United States National Oceanic and Atmospheric Administration.  
No decompression time  
The maximum amount of time a diver may remain at a particular depth without  
having to make decompression stops during the subsequent ascent.  
57  
 
 
No decompression dive  
Any dive which permits a direct, uninterrupted ascent to the surface at any  
time.  
NO DEC TIME  
OEA = EAN = EANx  
OLF  
Abbreviation for no decompression time limit.  
Abbreviations for oxygen enriched air nitrox.  
Abbreviation for oxygen limit fraction.  
OTU  
Abbreviation for oxygen tolerance unit.  
Used to measure the whole-body-toxicity.  
Oxygen tolerance unit  
Oxygen limit fraction  
A term used by Suunto for the values displayed in the oxygen toxicity bar graph.  
The value is either the CNS% or the OTU%.  
O2%  
Oxygen percentage or oxygen fraction in the breathing gas. Standard air has  
21% oxygen.  
Oxygen partial pressure  
Limits the maximum depth to which the nitrox mixture can be safely used. The  
maximum partial pressure limit for enriched air diving is 1.4 bar. The contingency  
partial pressure limit is 1.6 bar. Dives beyond this limit risk immediate oxygen  
toxicity.  
PFO  
Abbreviation for patent foramen ovale. It is a form of congenital heart defect  
that enables blood flow between the left and right atria via the interatrial septum.  
PO2  
Abbreviation for oxygen partial pressure.  
RGBM  
Abbreviation for Reduced Gradient Bubble Model.  
Modern algorithm for tracking both dissolved and free gas in divers.  
Reduced Gradient Bubble Model  
Repetitive dive  
Any dive whose decompression time limits are affected by residual nitrogen  
absorbed during previous dives.  
Residual nitrogen  
SURF TIME  
The amount of excess nitrogen remaining in a diver after one or more dives.  
Abbreviation for surface interval time.  
Surface interval time  
Elapsed time between surfacing from a dive and beginning a descent for the  
subsequent repetitive dive.  
Technical dive  
Tissue group  
A dive made with two or more breathing gas mixes.  
Theoretical concept used to model bodily tissues for the construction of decom-  
pression tables or calculations.  
Trimix  
A breathing gas mix of helium, oxygen and nitrogen.  
UHMS  
Abbreviation for Undersea and Hyperbaric Medical Society.  
Whole-body toxicity  
Another form of oxygen toxicity, which is caused by prolonged exposure to  
high oxygen partial pressures. The most common symptoms are irritation in  
the lungs, a burning sensation in the chest, coughing and reduction of the vital  
capacity. Also called Pulmonary Oxygen Toxicity. See also OTU.  
58  
 
CUSTOMER SERVICE CONTACTS  
Global Help Desk +358 2 284 11 60  
Suunto USA Phone +1 (800) 543-9124  
Canada Phone  
Suunto website  
+1 (800) 267-7506  
COPYRIGHT  
This publication and its contents are proprietary to Suunto Oy.  
Suunto, Dive Computer, Suunto HelO2 and their logos are registered or unregistered  
trademarks of Suunto Oy. All rights reserved.  
Whilewehavetakengreatcaretoensurethatinformationcontainedinthisdocumentation  
is both comprehensive and accurate, no warranty of accuracy is expressed or implied.  
Its content is subject to change at any time without notice.  
 
 
 
 
 
© Suunto Oy 4/2009  
 

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