Rebreather Maintenance

[ghosch]

There are a number of tests that you put a rebreather through prior to diving it.

One of them is a positive test, where you inflate the system until the relief valve relieves, let the system sit, and ensure that there are no positive pressure leaks. In the case of the Dolphin, you set a 5lb weight on the breathing bag, if it drops you know there is a leak. The positive check on the Inspiration is somewhat less scientific.

A negative test is just the opposite. Using your lungs you evacuate all of the gas from the breathing loop and "scrunch" up the breathing hoses. If there is no leak the hoses will stay kinked. If you come back 5 minutes later and find the hoses are no longer kinked, you know you have a leak to find.

Both tests are designed to ensure the integrity of the loop prior to diving the unit.