Dive Computer Pressure Testing
Whenever we carry out repair work or a battery change to a dive computer we perform a pressure test which will indicate whether all the dive computer seals are fully intact and properly seated. We always follow a set routine when pressure testing that will make it obvious to the technician that there is a problem without causing any water damage to the internals of the computer.
To carry out the test we need a chamber that provides both air and water pressurisation like the one shown here. As with all things, a good, reliable and accurate test chamber is expensive. To begin we suspend the computer in the air and then pressurise the chamber to approximately four atmospheres. Should the dive computer have a damaged seal around any of the push buttons or battery compartment this will allow harmless air to be forced into the spaces. Once a suitable amount of time has passed the computer is submerged into the water before being rapidly depressurised, causing the air to expand quickly. If there is a leak it will be visible as a stream of bubbles that the technician will be able to identify.
Assuming the air pressure test is passed successfully then dive computer moves on to a function test in which the computer is submerged and pressurised to 30m. The purpose of the test is to ensure the dive computer accurately measures the depth compared to the chamber analogue gauge, records time and nitrogen loading. After a short dive period the chamber is quickly depressurised to safety stop depth to trigger the ascent alarms and stop warnings. The computer is then left to finish any mandatory stops to prevent unnecessary penalisation before being slowly ascended to surface pressure and removed from the water. A final check of the memory log and no-fly timer before the dive computer is prepared for return to the customer.
This provides a thorough test of all the critical elements of the dive computer and can take some time to complete which is why a customer walking into the store for a battery change may need to wait a while, especially if our technicians are already busy performing tests. If you need to bring in your dive computer for an urgent battery change we always calling the store directly before hand to let us know you're coming.
