Suunto is committed to achieving Level AA conformance for this website in conformance with the Web Content Accessibility Guidelines (WCAG) 2.0 and achieving compliance with other accessibility standards. Please contact Customer Service at USA +1 855 258 0900 (toll free), if you have any issues accessing information on this website.

Suunto D4i User Guide

Tank pressure

When using the optional Suunto Wireless Transmitter, the pressure of your tank is shown in the lower left of the display.

Whenever you start a dive, the remaining air time calculation begins. After 30-60 seconds, the first estimation of remaining air time is shown in the left center of the display.

The calculation is always based on the actual pressure drop in your tank and automatically adapts to your tank size and current air consumption.

tank pressure Dseries

The change in your air consumption is based on constant one second interval pressure measurements over periods of 30–60 seconds. An increase in air consumption decreases the remaining air time rapidly, while a drop in air consumption increases the air time slowly. In this way, an overly optimistic air time estimate, caused by a temporary drop in air consumption, is avoided.

The remaining air time calculation includes a 35 bar (500 psi) safety reserve. This means that when the instrument shows the air time to be zero, there is still a small reserve.


Filling your BCD affects the air time calculation due to the temporary increase in air consumption.

The remaining air time is not displayed when either deepstops or the decompression ceiling has been activated. You can check remaining air time by keeping DOWN pressed.

Temperature changes affect the tank pressure and consequently the air time calculation.

Low air pressure warnings

The dive computer warns you with two (2) audible double beeps and a blinking pressure display when the tank pressure reaches 50 bar (700 psi).

Two (2) double beeps sound when the tank pressure reaches the defined alarm pressure and when the remaining time reaches zero.

Wireless transmission

To enable wireless transmission of tank pressure data to Suunto D4i requires:

  1. Installation of Suunto Wireless Transmitter onto your regulator.
  2. Pairing the transmitter to your Suunto D4i.
  3. Enabling the wireless integration in your Suunto D4i settings.

The transmitter enters power saving mode with slower data transmission rate if the tank pressure remains unchanged for more than five (5) minutes.

The optional transmitter sends out a low battery (batt) warning when its battery voltage is getting low. This is shown intermittently instead of the pressure reading. When you get this warning, the tank pressure transmitter's battery needs to be replaced.

Installing and pairing transmitter

When purchasing the Suunto Wireless Transmitter, we strongly recommend that you have your Suunto representative attach the transmitter to the first stage of your regulator.

The unit needs to be undergo a pressure test after installation and typically this requires a trained technician.

In order to receive wireless data, the transmitter and the Suunto D4i need to be paired.

The wireless transmitter activates when the tank pressure exceeds 15 bar (300 psi). The transmitter then starts sending pressure data together with a code number.

When your Suunto D4i is within 0.3 m (1 ft) of the transmitter, it receives and stores that code. The transmitter and Suunto D4i are now paired. Suunto D4i will then display the pressure data it receives with this code. This coding procedure prevents data mix-up from other divers also using a Suunto Wireless Transmitter.


The pairing procedure normally only needs to be done once. You may need to redo the pairing procedure if another diver in your group uses the same code.

To assign a new transmitter code:

  1. Slowly open the tank valve fully to pressurize the system.
  2. Immediately close the tank valve.
  3. Quickly depressurize the regulator so that the pressure is reduced to less than 10 bar (145 psi).
  4. Wait about 10 seconds, and slowly open the tank valve again to re-pressurize above 15 bar (300 psi).

The transmitter assigns a new code automatically. To re-pair the transmitter with your Suunto D4i:

  1. While in a dive mode other than Free, keep DOWN pressed to enter the settings.
  2. Press DOWN to scroll to Tank Press Pairing and press SELECT.
  3. Make sure Tank Press Pairing is set to On and press SELECT.
  4. A code number is displayed. Press UP to clear the code.
  5. Press SELECT.
  6. Press MODE to exit.

With the system pressurized to above 15 bar (300 psi), bring your Suunto D4i close to the transmitter. When pairing is completed, the dive computer displays the new code number and the transmitted tank pressure.

The wireless transmitter indicator is displayed every time a valid signal is received.

Transmitted data

After pairing, your Suunto D4i receives tank pressure data from the transmitter.

Any time the Suunto D4i receives a signal, one of the following symbols is shown in the lower left corner of the display.

Cd:–No code stored, the dive computer is ready for pairing with the transmitter.
Cd:10Current code number. Code number can be from 01 to 40.
- - -The flash symbol is blinking. Pressure reading exceeds allowed limit (over 360 bar (5220 psi)).
Last pressure reading followed by no connTank pressure data has not been updated for 1 minute. See below for solutions.
- - - followed by no connTank pressure data has not been updated for 5 minutes. See below for solutions.
no conn

Text no conn is displayed when the unit receives no data from the transmitter.

The pressure reading has not been updated for over a minute. The last received pressure blinks on and off. The flash symbol is not displayed.

This state may be caused by the :

  1. Transmitter being out of range (>1.2 m (4 ft))

  2. Transmitter is in power saving mode

  3. Transmitter is using a different code. To correct this:

Activate the transmitter by breathing off the regulator. Bring the dive computer closer to the transmitter and check if the flash symbol appears. If it does not, re-pair the transmitter to get a new code.

battPressure transmitter battery voltage is low. Change the transmitter battery!

Tank pressure alarm

There are two tank pressure alarms. The first is fixed at 50 bar (700 psi) and cannot be changed.

The second is user configurable. It can be turned on or off and can be used for a pressure range of 10–200 bar (200-3000 psi).

To set the tank pressure alarm value:

  1. While in a dive mode, keep DOWN pressed to enter settings.
  2. Press DOWN to scroll to Tank Press Alarm and press SELECT.
  3. Press UP to turn the alarm on and confirm with SELECT.
  4. Adjust the pressure level with UP or DOWN and confirm with SELECT.
  5. Press MODE to exit.

Air time

Air time can only be displayed when a wireless tank pressure transmitter is installed and in use.

To activate air time:

  1. While in a dive mode, keep DOWN pressed.
  2. Press DOWN to scroll to Air Time.
  3. Press UP to turn on the air time reading.
  4. Press SELECT.
  5. Press MODE to exit.

Table of Content