Suunto D4 User Manual

EN

1. WELCOME TO THE WORLD OF SUUNTO DIVING INSTRUMENTS .. ... .. .. ... 7

2. WARNINGS, CAUTIONS, AND NOTES .. .... . . . . . ... . . . . . ... . . . . . .. . . . . . ... . . . . . ... . 9

3. SUUNTO D4 AT A GLANCE .... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... 15

3.1. Navigating in the menus . . .. . . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . .. 15

3.2. Button symbols and functions ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . 16

4. GETTING STARTED WITH YOUR SUUNTO D4 . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . 19

4.1. TIME mode settings . . . . . ... . . . . . ... . . . . . .. . . . . . ... . . . . . ... . . . . . .. . . . . . ... . . . . . ... 19

4.1.1. Setting the alarm . . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . . 20

4.1.2. Setting the time . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . 21

4.1.3. Setting the dual time .... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . . 21

4.1.4. Setting the date ... . . . . . ... . . . . . ... . . . . . .. . . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . 22

4.1.5. Setting the units . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... 22

4.1.6. Setting the backlight . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . . 23

4.1.7. Setting the tones . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . 23

4.2. Stopwatch . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . .. 24

4.3. AC water contacts . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . . .. . . . . . ... . . . . . ... . . . . 24

5. BEFORE DIVING ... . . . . . ... . . . . . .. . . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . . 26

5.1. The Suunto RGBM/Deep Stop Algorithm .... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . 27

5.2. Emergency ascents .. ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . 27

5.3. Dive computer limitations .. . . . . . ... . . . . . ... . . . . . .. . . . . . ... . . . . . ... . . . . . ... . . . . ... 28

5.4. Nitrox . . ... . . . . . .. . . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . 28

5.5. Free diving .. . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . 29

5.6. Audible and visual alarms .. . . . . . .. . . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . .. 29

5.7. Error conditions . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . . .. . . . . . ... . . . . . ... . . . . . 32

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5.8. DIVE mode settings . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . . .. . . . . . ... . . . . . ... . . . . 33

5.8.1. Setting the depth alarm . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . . .. . . . . . .. 35

5.8.2. Setting the depth notify alarm (FREE mode) .. ... . . . . ... . . . . . ... . . . . . ... . 36

5.8.3. Setting the dive-time alarm .... . . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . . 36

5.8.4. Setting the nitrox values . . ... . . . . . .. . . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . 37

5.8.5. Setting the personal/altitude adjustments . . . . . ... . . . . . ... . . . . . ... . . . . ... . 37

5.8.6. Setting the surface time notify alarm (FREE mode) . . . . . ... . . . . . ... . . . . . 38

5.8.7. Setting the sample rate . ... . . . . ... . . . . . ... . . . . . ... . . . . . .. . . . . . ... . . . . . ... . . . 38

5.8.8. Setting the Deep Stops . ... . . . . . .. . . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . 39

5.8.9. Setting the RGBM values .. ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . .. 39

5.9. Activation and pre-checks .. . . ... . . . . ... . . . . . ... . . . . . ... . . . . . .. . . . . . ... . . . . . ... . . 39

5.9.1. Accessing DIVE mode . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . 40

5.9.2. DIVE mode activation .. . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . . .. . . . . . .. 40

5.9.3. Battery power indication . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . . .. . . . . . ... . 42

5.9.4. Diving at altitude .... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . . .. . . . . . ... . . . 42

5.9.5. Personal adjustments .. . . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . .. 44

5.10. Safety Stops . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . 46

5.10.1. Recommended Safety Stops . ... . . . . . ... . . . . . .. . . . . . ... . . . . . ... . . . . . ... . . 46

5.10.2. Mandatory Safety Stops .. . ... . . . . . .. . . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . . 47

5.11. Deep stops . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . . .. . . . . 49

6. DIVING . . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . 50

6.1. Diving in AIR mode (DIVEair) . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . . 50

6.1.1. Basic dive data . . . ... . . . . . ... . . . . . .. . . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . 50

6.1.2. Bookmark . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . . .. . . . . . ... . . . . . ... . . . . . .. 52

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6.1.3. Ascent rate indicator ..... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . . 52

6.1.4. Decompression dives . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . 53

6.2. Diving in NITROX mode (DIVEnitrox) . . . . ... . . . . . ... . . . . . .. . . . . . ... . . . . . ... . . . . 58

6.2.1. Before diving in NITROX mode . . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . 58

6.2.2. Oxygen displays . . . . . ... . . . . . ... . . . . . .. . . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . .. 59

6.2.3. Oxygen limit fraction (OLF) ... . . . . ... . . . . . ... . . . . . ... . . . . . .. . . . . . ... . . . . . .. 61

6.3. Diving in FREE mode (DIVEfree) ... . . . . . ... . . . . . ... . . . . . .. . . . . . ... . . . . . ... . . . . 61

6.3.1. Day History ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . . .. . . . . . ... . . . . . ... . . . . . ... . 62

6.3.2. Free dive time limit .. . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . . 64

7. AFTER DIVING . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . 65

7.1. Surface interval . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . 65

7.2. Dive numbering . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . . .. . . . . . ... . . . . . ... . . . . . 66

7.2.1. AIR and NITROX .. . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . . .. . . . . 66

7.2.2. FREE Dive .. . . . . . ... . . . . . .. . . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . 67

7.3. Repetitive dive planning . . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . 67

7.4. Flying after diving .. ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . . 67

7.5. MEMORY mode .. ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . .. 68

7.5.1. Dive Planning mode (MEMPlan) .. ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . .. 69

7.5.2. Dive logbook (MEMLogbook) .. . . .. . . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . 71

7.5.3. Dive history (MEMHistory) .. . ... . . . . . ... . . . . . ... . . . . . .. . . . . . ... . . . . . ... . . . . 73

7.6. Suunto Dive Manager (SDM) ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . . .. . . . 74

7.7. www.suuntosports.com and Suunto Diving World at

www.suunto.com/diving . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . . .. . . . 76

8. CARE AND MAINTENANCE OF MY SUUNTO DIVING COMPUTER ... . . . . . .. 77

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9. BATTERY REPLACEMENT . . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . . .. . . . . . ... . . . . 82

10. TECHNICAL DATA . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . . .. . . . . . ... . . . . . .. 83

10.1. Technical specifications ... . . . . . .. . . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . .. 83

10.2. RGBM . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . . .. . . 86

10.2.1. Suunto RGBM adaptive decompression ..... . . . . ... . . . . . ... . . . . . ... . . . . 87

10.2.2. No-decompression limits ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . . .. . 88

10.2.3. Altitude diving . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . 91

10.3. Oxygen exposure .. . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . . .. . . . . . ... . . . . . ... . . . . . ... 91

11. INTELLECTUAL PROPERTY . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . 93

11.1. Copyright . . . .. . . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . . 93

11.2. Trademark . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . 93

11.3. Patent notice . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . . .. 93

12. DISCLAIMERS . . . ... . . . . . .. . . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . 94

12.1. User’s responsibility ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . . .. . . . . . ... . . . 94

12.2. CE .. . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . 94

13. SUUNTO LIMITED WARRANTY for Suunto diving computers and Suunto Diving

computer accessories . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . 95

14. DISPOSAL OF THE DEVICE .. . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . . .. . . . . . ... . . 101

GLOSSARY .. ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . . ... . . . . . ... . . . . ... . . . . 102

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1. WELCOME TO THE WORLD OF SUUNTO DIVING INSTRU­MENTS

Suunto D4 was designed to help you get the most out of your diving.

Suunto D4 simplifies your diving experience because all the information you need re­lating to depth, time and decompression status is available on one easy-to-read screen.

7

To get the most out of your Suunto D4 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.

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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:

WARNING

is used in connection with a procedure or situation that could
result in serious injury or death

CAUTION

NOTE

Before you go on to read the manual itself, it is extremely important that you read the
following warnings. These warnings are intended to maximize your safety while using
Suunto D4 and must not be ignored.

WARNING

is used in connection with a procedure or situation that could
result in damage to the device

is used to emphasize important information

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.

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WARNING

NOT FOR PROFESSIONAL USE! Suunto dive computers are
intended for recreational use only. The demands of commercial
or professional 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

WARNING

10

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.

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 remain 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.

WARNING

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
SELECTED O2% AND A MAXIMUM PO2OF 1.4 BAR!

WARNING

WARNING

WARNING

DIVES THAT REQUIRE DECOMPRESSION STOPS ARE NOT
RECOMMENDED. YOU SHOULD ASCEND AND BEGIN DE­COMPRESSION IMMEDIATELY WHEN THE DIVE COMPUTER
SHOWS YOUTHAT A DECOMPRESSION STOP IS REQUIRED!
Note the blinking ASC TIME symbol and the upward pointing ar­row.

USE BACK-UP INSTRUMENTS! Make sure that you use back­up instrumentation, including a depth gauge, submersible pressure
gauge, timer or watch, and have access to decompression tables
whenever diving with the dive computer.

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.

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WARNING

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

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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 computer 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 DIVE WITH A CYLINDER OF ENRICHED AIR 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% into your dive computer will result in incorrect dive
planning information.

WARNING

THE DIVE COMPUTER WILL NOT ACCEPT FRACTIONAL
PERCENTAGE 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 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 PO
setting to affect oxygen exposure.

2

WARNING

WARNING

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 calculate 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.

SELECT THECORRECT 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.

13

WARNING

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.

NOTE

14

It is not possible to change between AIR, NITROX and FREE
DIVE modes before the instrument has counted down the no-fly
time.
There is one exception to this: You can change from AIR to NI­TROX mode even during the no-fly time. When planning both air
and nitrox dives during the same dive series, you should set the
instrument in NITROX mode and modify the gas mix accordingly.

3. SUUNTO D4 AT A GLANCE

U

P

D

O

W

N

S

E

L

E

C

T

M

O

D

E

Safety Stop Indicator

No-Fly Icon

Diver Attention Symbol

Date
Dual Time
Maximum Depth
O2(Nitrox Mode)
Time

Ascent Rate Bar Graph

Active Water Contact
Indicator

Seconds Display
Stopwatch
Weekday
Dive Time

Temperature
PO2 (Nitrox Mode)
OLF% (Nitrox Mode)

Current Time Display
Mode Indicator
No-Decompression Time
Total Ascent Time
Ceiling Depth
Safety/Deep Stop Time
Surface Interval Time
No-Fly Time

Dive Alarm Indicator

Daily Alarm Indicator

Dive Number

Low Battery Warning

Present Depth

3.1. Navigating in the menus

Suunto D4 has three main operating modes - TIME mode (TIME), DIVE mode (DIVE),
and MEMORY mode (MEM). To toggle between the main modes, press the MODE
button. To select a submode in DIVE and MEM modes, press the UP/DOWN buttons.

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3.2. Button symbols and functions

The table below explains the main functions of the dive computer's buttons. The buttons
and their use will be explained in more detail in the relevant sections of the manual.

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Table 3.1. Button symbols and functions

Main functionsPressButtonSymbol

ShortMODE

Switch between main modes
Switch from submode to main mode
Activate backlight in DIVE mode

Activate backlight in other modesLongMODE

ShortSELECT

ShortUP

ShortDOWN

Select a submode
Select and accept settings
Displays Day History in FREE mode (free dive mode)

Toggle between alternative displays
Change submode
Increase values
Change shortcuts in TIME and DIVE modes

Toggle between alternative displays
Change submode
Decrease values
Change shortcuts in TIME and DIVE modes

17

18

Main functionsPressButtonSymbol

LongDOWN

Enter Setting mode

4. GETTING STARTED WITH YOUR SUUNTO D4

To get the most out of your Suunto D4, take some time to personalize it and really
make it YOUR computer. Set the correct time and date, as well as the alarms and
tones, unit and backlight settings.

Suunto D4 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 D4, is to set the alarm, time, dual
time, date, units, backlight, and tones. In this section, we look at how to do this.

Before that, however, take a look at the figure below, which shows how to toggle
between different shortcuts in the TIME mode.

NOTE

The seconds display reverts to date display after 5 minutes in
order to save battery power.

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NOTE

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USE UP AND DOWN BUTTONS
TO TOGGLE BETWEEN ALARM, TIME,
DUAL TIME, DATE, UNITS, BACKLIGHT
AND TONES.

The display is illuminated by holding down the MODE button for
more than 5 seconds.

Now that you know how to toggle between the shortcuts, you can start to set them.
The following figure shows how to enter the TIME SETTINGS menu.

4.1.1. Setting the alarm

The dive computer has a daily alarm function. When the daily alarm activates, the
screen blinks and the alarm sounds for 24 seconds. Press any button to stop the
alarm.

20

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4.1.2. Setting the time

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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.

4.1.3. Setting the dual time

In the DUAL TIME SETTING mode you can select the hour and minute of a dual time

- useful when traveling to a different time zone.

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4.1.4. Setting the date

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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.

4.1.5. 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.

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4.1.6. Setting the backlight

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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.

4.1.7. Setting the tones

The TONE SETTING mode allows you to activate or deactivate the tones.

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NOTE

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AC APPEARS IN THE TOP RIGHT

CORNER OF THE DISPLAY, WHEN THE DIVE

COMPUTER IS IN CONTACT WITH WATER.

THIS ALSO ACTIVATES THE DIVE MODE.

When the tones are off, there are no audible alarms.

4.2. Stopwatch

The Suunto D4’s stopwatch measures elapsed and split times.

4.3. AC water contacts

The water and data transfer contact is located on the side 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.

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Contamination or dirt on the water contact may prevent this automatic activation. It is

U

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M

O

D

E

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.

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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 D4 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 D4 is an outstanding tool for assisting properly trained,

certified divers in planning and executing sport dives. It is NOT A SUBSTITUTE FOR
CERTIFIED SCUBA INSTRUCTION, including training in the principles of decompres­sion.

WARNING

Do not attempt to dive with any gas mix other than standard air without first receiving
certified training in this specialty.

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Diving with enriched air mixtures (nitrox) exposes you to risks
that are different from those associated with diving with standard
air. These risks are not obvious, and require training to understand
and avoid. Risks include possible serious injury or death.

5.1. The Suunto RGBM/Deep Stop Algorithm

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YOU ARE ADVISED TO MAKE A

DEEPSTOP AT 12 M. THE SECOND
INDICATOR SHOWS THAT YOU HAVE 58
SECONDS LEFT OF YOUR DEEPSTOP.

Suunto’s Reduced Gradient Bubble Model (RGBM), utilized in the Suunto D4, 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.

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.

5.2. Emergency ascents

In the unlikely event that the dive computer malfunctions during a dive, follow the
emergency procedures provided by your certified dive training agency or, alternatively,
follow these steps:

Assess the situation calmly and then move promptly to less than 18 m/60 ft.

1.
At 18 m/60 ft, slow down your ascent rate to 10 m/33 ft per minute and move to

2.
a depth between 3 and 6 m/10 and 20 ft.

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Stay there for as long as your air supply will safely allow. After reaching the sur-

3.
face, do not dive for at least 24 hours.

5.3. 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.

5.4. Nitrox

Diving with nitrox provides you with an opportunity to increase bottom times or reduce
the risk of decompression illness by reducing the nitrogen content in the gas mix.

However, when the gas mix is altered, the oxygen content of the mix 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
concentrations of oxygen present a fire or explosion hazard. Consult the manufacturer
of your equipment to check its compatibility with nitrox.

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5.5. Free diving

Free diving, and particularly Free diving in combination with scuba diving, may present
risks that have not been researched and are not commonly known.

Anyone who engages in any form of breath hold diving is in danger of shallow-water
blackout (SWB), that is, the sudden loss of consciousness caused by oxygen starvation.

Any breath hold diving results in some nitrogen build-up in the blood and other fast
tissues. Due to the short time spent at depth, this build-up is generally not significant.
Therefore, provided the effort involved in Free diving has not been severe, there is
little risk in diving after breath hold diving. However, the reverse is more unknown and
may significantly increase the risk of DCI. Therefore, FREE DIVING AFTER SCUBA
DIVING IS NOT RECOMMENDED. You should avoid Free diving, and not exceed 5
m/16 ft, for at least two hours after scuba diving.

WARNING

5.6. Audible and visual alarms

The dive computer features 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.

Suunto also recommends that you receive training in Free diving
techniques and physiology before conducting breath hold dives.
No dive computer can replace the need for proper dive training.
Insufficient or improper training may cause a diver to commit errors
that may lead to serious injury or death.

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Table 5.1. Audible and visual alarm types

Alarm reasonAlarm type

Dive computer is activated.Short single beep

Dive computer automatically returns to the TIME mode.

Three beeps with a three
second interval and activated
backlight

Continuous beeps and activ­ated backlight

You are able to preset alarms before the dive for maximum depth, dive time and time.
See also Section 5.8. DIVE mode settings and Section 4.1. TIME mode settings.

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No-decompression dive turns into a Decompression
Stop dive. An arrow pointing upwards and the blinking
ascent warning ASC TIME will appear.

Maximum allowed ascent rate, 10 m per min/33 ft per
min, is exceeded. Ascent rate bar graph blinks and
STOP warning appears.

Decompression ceiling depth is exceeded. An Error
warning (Er) and a downward pointing arrow appear.
You should immediately descend to, or below, the
ceiling. The instrument will otherwise enter a perman­ent Error mode within three minutes, indicated by a
permanent Er symbol.

Table 5.2. Preset alarm types

Continuous beep series for 24 seconds
Maximum depth blinks as long as the current depth

value exceeds the preset value.

Continuous beep series for 24 seconds or until any
button is pressed.

Dive time blinks for one minute.

Continuous beep series for 24 seconds or until any
button is pressed.

Current time blinks for one minute

Table 5.3. Oxygen alarms in NITROX mode

Continuous beeps for 3
minutes and activated back­light

Set oxygen partial pressure limit is exceeded. The al­ternative display is replaced with a current blinking
PO2value. You should immediately ascend above the
PO2depth limit.

OLF value reaches 80%. The OLF value will start to
blink.

OLF value reaches 100%. The OLF value will blink.

Alarm reasonAlarm type

Preset maximum depth has
been exceeded.

Preset dive time has been ex­ceeded.

Preset alarm time is reached.

Alarm reasonAlarm type

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