PADI - Professional Association of Diving Instructors Scuba Equipment Assembly & Function Questions and Answers

Question 1

What is the primary function of the first stage of a scuba regulator?

Accepted Answer

To reduce the high pressure from the cylinder to an intermediate pressure.

Answer

To connect the Buoyancy Control Device (BCD) to the cylinder for inflation.

Answer

To provide the diver with a mouthpiece to breathe from.

Answer

To display the remaining air pressure in the cylinder.

Question 2

After attaching your regulator to the cylinder and slowly opening the valve, you hear a loud, continuous hissing sound coming from the connection point. What is the most likely cause and immediate correct action?

Accepted Answer

The yoke or DIN O-ring is missing, damaged, or improperly seated; you should turn off the air and inspect the O-ring.

Answer

The second stage is free-flowing; you should press the purge button repeatedly to stop it.

Answer

The cylinder is overfilled; you should immediately close the valve and seek professional assistance.

Answer

This is normal pressurization of the system; you should continue with your pre-dive check.

Question 3

Which of the following is a critical safety feature of a scuba cylinder valve designed to prevent catastrophic failure from over-pressurization?

Accepted Answer

The burst disk

Answer

The DIN/Yoke insert

Answer

The handwheel

Answer

The dip tube

Question 4

When performing the 'A' (Air) step of the PADI pre-dive safety check (BWRAF), what should you and your buddy do after confirming the cylinder valve is fully open?

Accepted Answer

Breathe several times from the primary second stage while watching the SPG for any needle fluctuation.

Answer

Orally inflate the BCD completely to test the over-pressure valves.

Answer

Disconnect and reconnect the low-pressure inflator hose.

Answer

Check that all releases are secure and know how to operate them.

Question 5

When assembling your scuba unit, what is the correct procedure for attaching the regulator to the cylinder valve?

Accepted Answer

Align the first stage with the valve outlet, tighten the yoke screw or DIN fitting until it is snug (finger tight), and then attach the low-pressure inflator hose.

Answer

Attach the low-pressure inflator hose to the BCD first, then attach the first stage to the cylinder.

Answer

Open the cylinder valve slightly to blow out any debris, then attach the first stage without inspecting the O-ring.

Answer

Tighten the yoke screw with a wrench to ensure it is completely sealed, then open the valve as fast as possible.

Question 6

The Submersible Pressure Gauge (SPG) is connected to which part of the regulator first stage?

Accepted Answer

A high-pressure (HP) port.

Answer

A low-pressure (LP) port.

Answer

The same port as the primary second stage.

Answer

The over-pressure relief valve.