The purpose of the pre-check is to check the gas cylinder pressure, adapter hose non-return valves, low gas whistle and RED pressure.

1. RED Cylinder pressure:

Set the DPX switch valve in DECO position.

Connect a RED adaptor hose to a RED gas cylinder and the second adaptor hose to the gas outlet.

Open and close the cylinder valve to pressurize the system.

Check that the gas cylinder has more than 200 bar.

1. RED Non-return valve

Open the bleed valve on the gas cylinder side slowly.

Check that the pressure does not drop (Non-return valve OK)

1. RED low gas whistle

Open the bleed valve on the gas outlet side slowly.

Check that the RED low gas whistle sounds at approximately 55 bar. (RED low gas whistle OK)

1. RED pressure

Depressurize and disconnect the adaptor hose from the gas outlet.

Connect a BLUE adaptor hose to the gas outlet.

Open and close the RED cylinder valve to pressurize the system.

Check that the BLUE pressure gauge shows 25 bar (RED pressure OK)

Depressurize and disconnect the BLUE adapter hose.

1. RED 2:nd cylinder pressure and 2:nd non-return valve

Connect a second gas cylinder to the loose adapter hose.

Move the first adapter hose from the first gas cylinder to the gas outlet.

Repeat the test instructions 1 to 3 above.

Depressurize and reconnect the first cylinder to the first adapter hose so that two cylinders are connected.

If further gas cylinders shall be used, test instruction 1 above can be used to check the cylinder pressure. The DPX can now be prepared for diving.