BAT Backflow Assembly Tester Evaluation & Troubleshooting 3 — Questions and Answers
Question 1: A Pressure Vacuum Breaker (PVB) is being tested and the air inlet valve fails to open when the supply pressure is reduced to zero. What should the tester do?
- Record as a pass because the check held
- Record the PVB as failed due to a malfunctioning air inlet (Correct answer)
- Add lubricant to the air inlet and re-test on site
- Test again with higher inlet pressure
Correct answer: Record the PVB as failed due to a malfunctioning air inlet
If the air inlet valve does not open fully when pressure is reduced to zero, the PVB fails because it cannot provide an air break during a backsiphonage event.
Question 2: Which backflow preventer type provides protection ONLY against backsiphonage and NOT backpressure?
- Reduced Pressure Assembly (RP)
- Double Check Valve Assembly (DCVA)
- Pressure Vacuum Breaker (PVB) (Correct answer)
- Spill-Resistant Vacuum Breaker (SVB)
Correct answer: Pressure Vacuum Breaker (PVB)
A PVB is only rated for backsiphonage protection; it must be installed at least 12 inches above all downstream piping and cannot withstand sustained backpressure.
Question 3: A tester measures an RP relief valve opening point at 1.5 psi. The manufacturer's specification requires it to open at 2.0 psi or below the zone 1 differential. What is the correct action?
- Pass — the opening point is below the maximum allowed (Correct answer)
- Fail — the relief valve opens too early and must be repaired
- Conditional pass — document and retest in 60 days
- No action required since check #1 is still holding
Correct answer: Pass — the opening point is below the maximum allowed
An RP relief valve that opens at 1.5 psi meets the requirement since it must open before the zone 1 differential drops below 2.0 psi, preventing backflow.
Question 4: What test method is used to verify the relief valve opening point on an RP assembly?
- Close both shutoff valves and observe discharge
- Slowly bleed the high-side hose while watching for relief valve discharge (Correct answer)
- Fully open needle valve #2 and monitor middle chamber pressure
- Apply downstream backpressure to the zone and observe relief valve
Correct answer: Slowly bleed the high-side hose while watching for relief valve discharge
Slowly bleeding the high-side hose reduces the check #1 differential until the relief valve opens, indicating its opening threshold.
Question 5: During an RP test, the tester observes the relief valve discharging continuously even at full supply pressure with no downstream flow. What is the most likely cause?
- Supply pressure is too high for the assembly
- Check valve #1 has failed, collapsing the differential below the relief valve threshold (Correct answer)
- The downstream isolation valve is closed
- Test cock #2 is clogged with debris
Correct answer: Check valve #1 has failed, collapsing the differential below the relief valve threshold
If check valve #1 fails to hold the required differential, the zone pressure rises until the relief valve must open continuously to prevent backflow.
Question 6: A DCVA is installed to protect against a high-hazard connection. What action should the tester take?
- Test it normally — DCVAs are appropriate for all hazard levels
- Fail the installation and recommend upgrading to an RP assembly (Correct answer)
- Pass the assembly if both checks hold 1 psi
- Notify the authority having jurisdiction that the DCVA may be undersized
Correct answer: Fail the installation and recommend upgrading to an RP assembly
DCVAs are only approved for low-hazard (non-health) connections; a high-hazard connection requires an RP assembly per plumbing and water codes.
Question 7: A tester finds that test cock #3 on an RP assembly will not open fully and produces only a trickle of water. How should the tester proceed?
- Complete the test using the reduced flow and note it in the report
- Abort the test and report the test cock as obstructed — the assembly cannot be accurately tested (Correct answer)
- Use test cock #2 as a substitute for test cock #3
- Force the test cock open using pliers
Correct answer: Abort the test and report the test cock as obstructed — the assembly cannot be accurately tested
A clogged or malfunctioning test cock prevents reliable zone pressure readings, making an accurate test impossible; the assembly must be flagged for maintenance before retesting.
BAT Backflow Assembly Tester Evaluation & Troubleshooting 3
A Pressure Vacuum Breaker (PVB) is being tested and the air inlet valve fails to open when the supply pressure is reduced to zero.
What should the tester do?