PADI Scuba Equipment Assembly & Function 2 — Questions and Answers
Question 1: When attaching a BCD to a scuba cylinder, what is the correct position of the tank valve relative to the BCD backpack?
- Valve facing left
- Valve facing forward, away from the diver
- Valve facing the diver's back with the opening up (Correct answer)
- Valve facing right
Correct answer: Valve facing the diver's back with the opening up
The tank valve should face the diver's back with the opening pointing upward so the regulator first stage can be attached correctly.
Question 2: What is the purpose of the purge button on a second stage regulator?
- To adjust breathing resistance
- To flood the regulator for easy clearing
- To manually release air to clear the mouthpiece (Correct answer)
- To lock the regulator in standby mode
Correct answer: To manually release air to clear the mouthpiece
Pressing the purge button manually opens the valve to flush air through the mouthpiece, clearing water or debris.
Question 3: Which type of BCD inflator mechanism uses the diver's breath to add air to the bladder?
- Power inflator
- Oral inflator (Correct answer)
- Dump valve
- Integrated inflator
Correct answer: Oral inflator
The oral inflator allows divers to blow air into the BCD bladder by breathing into the inflator mouthpiece.
Question 4: A diver notices the submersible pressure gauge reads full even after several minutes of breathing. What is the most likely cause?
- The tank was overfilled
- The SPG hose is kinked or the gauge is faulty (Correct answer)
- The regulator is in environmental seal mode
- The first stage DIN fitting is loose
Correct answer: The SPG hose is kinked or the gauge is faulty
A gauge that doesn't move despite active breathing likely has a blocked hose or a defective pressure gauge that should not be used.
Question 5: What does it mean when a regulator is described as 'environmentally sealed'?
- It can only be used in saltwater
- Internal parts are protected from freezing water or contaminants (Correct answer)
- It is rated for zero-visibility diving
- The second stage is made of corrosion-proof plastic
Correct answer: Internal parts are protected from freezing water or contaminants
An environmentally sealed first stage uses a dry chamber or special diaphragm to prevent water from contacting internal parts, reducing freeze-up risk.
Question 6: When threading a DIN regulator first stage onto a cylinder valve, how should you verify a proper connection?
- Check that the valve knob turns freely
- Confirm the O-ring is visible and hand-tighten until snug with no gaps (Correct answer)
- Tighten with a wrench until resistance stops
- Ensure the SPG reads zero before opening the valve
Correct answer: Confirm the O-ring is visible and hand-tighten until snug with no gaps
The DIN fitting should be hand-tightened until flush and snug; gaps or cross-threading indicate a poor seal.
Question 7: What should a diver do if they hear continuous bubbling from the first stage regulator during the pre-dive equipment check?
- Adjust the breathing resistance knob
- Proceed with the dive and monitor air consumption
- Do not dive — the regulator has a leak and needs servicing (Correct answer)
- Turn the tank valve to half-open position
Correct answer: Do not dive — the regulator has a leak and needs servicing
Continuous bubbling indicates a leak in the first stage, which can rapidly deplete air supply and should be serviced before diving.
PADI Scuba Equipment Assembly & Function 2
When attaching a BCD to a scuba cylinder, what is the correct position of the tank valve relative to the BCD backpack?