BAT Troubleshooting & Diagnostics 2 — Questions and Answers
Question 1: During a field test of a double check valve assembly (DCVA), the #1 check valve shows a differential pressure reading of 0.8 psi. What does this indicate?
- The check valve is functioning correctly
- The check valve has failed and must be repaired or replaced (Correct answer)
- The check valve requires lubrication only
- The test kit gauge is malfunctioning
Correct answer: The check valve has failed and must be repaired or replaced
A differential pressure below 1.0 psi across a check valve in a DCVA indicates the check valve has failed and cannot hold the required minimum pressure.
Question 2: A reduced pressure principle assembly (RPBA) is found with the relief valve discharging continuously during normal system operation. What is the MOST likely cause?
- High supply pressure exceeding system design
- The #2 check valve is fouled or failed, allowing backpressure to exceed zone pressure (Correct answer)
- The test cock #1 is partially open
- The air gap is obstructed
Correct answer: The #2 check valve is fouled or failed, allowing backpressure to exceed zone pressure
Continuous relief valve discharge typically indicates a failed or fouled #2 check valve allowing downstream pressure to rise and compress the zone pressure above the relief valve opening point.
Question 3: When testing a pressure vacuum breaker (PVB), the air inlet valve fails to open at 1.0 psi differential. What should the tester do?
- Re-test the assembly three more times before making a determination
- Record the assembly as passed since it still prevents backflow
- Record the assembly as failed and require repair or replacement (Correct answer)
- Adjust the air inlet valve spring tension in the field
Correct answer: Record the assembly as failed and require repair or replacement
If the air inlet valve does not open at 1.0 psi differential, the PVB has failed the test and must be repaired or replaced per certification standards.
Question 4: A tester notices that test cock #4 of an RPBA is dripping during a test. What is the correct action?
- Ignore it since test cocks are not part of the assembly rating
- Note it in the report but continue testing as normal
- Stop the test and repair the test cock before proceeding (Correct answer)
- Replace the entire assembly immediately
Correct answer: Stop the test and repair the test cock before proceeding
A leaking test cock can compromise test accuracy and introduce contamination risk, so it must be repaired before completing the field test.
Question 5: During an RPBA test, the tester opens test cock #2 and the gauge reads the same pressure as supply. What does this most likely indicate?
- The relief valve is functioning correctly
- Check valve #1 is fully open and not holding differential pressure
- The zone pressure is correctly maintained
- The shutoff valve #1 is leaking by (Correct answer)
Correct answer: The shutoff valve #1 is leaking by
If TC #2 reads supply pressure, it suggests shutoff valve #1 is not fully closed and is allowing supply pressure to bleed through into the test setup.
Question 6: A DCVA field test shows the #2 check valve holds but the #1 check valve does not open when differential is applied. What is the correct interpretation?
- The assembly passes; only #2 check valve needs to hold
- The assembly fails because #1 check valve must open freely under differential (Correct answer)
- Both check valves must be replaced regardless
- The assembly requires retesting with a calibrated kit
Correct answer: The assembly fails because #1 check valve must open freely under differential
Both check valves in a DCVA must hold at least 1.0 psi differential; a #1 check valve that does not perform correctly constitutes a failure requiring repair.
Question 7: During testing, a tester finds the supply pressure to an RPBA is fluctuating widely. What is the best course of action?
- Proceed with testing and average the readings
- Contact the water purveyor to stabilize pressure before testing (Correct answer)
- Test only the check valves and skip the relief valve test
- Increase the test kit gauge range to compensate
Correct answer: Contact the water purveyor to stabilize pressure before testing
Fluctuating supply pressure produces unreliable differential readings, so the water purveyor should be contacted to stabilize pressure before a valid test can be completed.
BAT Troubleshooting & Diagnostics 2
During a field test of a double check valve assembly (DCVA), the #1 check valve shows a differential pressure reading of 0.8 psi.
What does this indicate?