Switch to dive mode when pressure testing Suuntos

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I just wanted to share a piece of advice I discovered while pressure testing a Suunto computer (D4f, but it's likely that most of them work the same way) - when you pressurize it in air, turn it on and switch to some kind of dive mode (free/gauge). If left in "TIME" mode, it will perform some kind of ambient pressure compensation and the depth readings when you switch it to dive mode again will be off by the amount of pressure it measured while in "TIME" mode. In "DIVE" mode, it will happily dive even when water contacts are not activated.

If you accidentally pressurize it in "TIME" mode, like I did, it will re-calibrate itself after some time at ambient pressure (provided it's left on in "TIME" mode).


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Fort Lauderdale, FL
# of dives
2500 - 4999

You're right and we are aware of the behavior you describe. Is definitely true with the Suunto D4's and D6's. It happens sometimes with the D9's whereas never happens with the older Stinger and Spyder. Our non-destructive Bergeon testing chamber requires pressurizing first the dive computer or watch under test in air and afterward dunking it in water. In the case of a leaky unit, when depressurizing the chamber you would see bubbles coming out from the leak point but the water never gets in the computer. So, when we pressure test a Suunto dive computer we set them in dive mode before closing the lid.

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