BAT Backflow Assembly Tester Evaluation & Troubleshooting 2 — Questions and Answers
Question 1: During a RP assembly test, the differential pressure across check valve #1 drops below the minimum threshold. What is the correct next step?
- Record it as a pass since any reading is acceptable
- Record the assembly as failed and tag it for repair (Correct answer)
- Re-test immediately without resetting the test kit
- Increase supply pressure and re-test
Correct answer: Record the assembly as failed and tag it for repair
If check valve #1 fails to hold the minimum required differential, the assembly must be recorded as failed and removed from service for repair.
Question 2: What condition is indicated when the middle chamber bleed-off of an RP backpressure reads HIGHER than supply pressure during testing?
- The relief valve is functioning correctly
- Backpressure is being applied from the downstream side (Correct answer)
- The differential pressure gauge is miscalibrated
- Check valve #2 has opened prematurely
Correct answer: Backpressure is being applied from the downstream side
A middle chamber pressure exceeding supply pressure indicates downstream backpressure is entering the zone through a failed check valve #2.
Question 3: When testing a Double Check Valve Assembly (DCVA), the tester finds that check valve #2 holds but check valve #1 leaks at 0.5 psi. What is the correct disposition?
- Pass — check valve #2 provides adequate protection
- Fail — both check valves must independently meet minimum hold pressure (Correct answer)
- Conditional pass pending re-test in 30 days
- Fail only if both checks fail simultaneously
Correct answer: Fail — both check valves must independently meet minimum hold pressure
Each check valve in a DCVA must independently hold a minimum differential pressure (typically 1.0 psi); a failure of either check requires the assembly to fail.
Question 4: A reduced pressure (RP) assembly's relief valve opens during normal flow conditions when no backflow condition exists. What is the most likely cause?
- Check valve #1 is fouled and not holding differential
- The relief valve seat is worn or debris-fouled, causing premature opening (Correct answer)
- Supply pressure is too low for the assembly
- The test cocks are partially open
Correct answer: The relief valve seat is worn or debris-fouled, causing premature opening
A worn or debris-fouled relief valve seat allows water to weep or open under normal pressure differentials, causing continuous or intermittent discharge.
Question 5: What is the minimum differential pressure an RP assembly's check valve #1 must hold during a field test per the USC FCCCHR standard?
- 0.5 psi
- 1.0 psi
- 3.0 psi
- 5.0 psi (Correct answer)
Correct answer: 5.0 psi
USC FCCCHR requires RP check valve #1 to maintain a minimum of 5.0 psi differential pressure to pass field testing.
Question 6: A tester closes needle valve #1 on the differential pressure gauge kit and the gauge reading drops to zero immediately. What does this indicate?
- Check valve #1 is holding tight
- There is a leak or failure at check valve #1 (Correct answer)
- The gauge is faulty and needs calibration
- Supply pressure has dropped to zero
Correct answer: There is a leak or failure at check valve #1
An immediate drop to zero when needle valve #1 is closed indicates check valve #1 is not holding and water is bleeding back through it.
Question 7: When performing a DCVA test, why must the tester bleed off the hose between the gauge and test cock #4 before reading check valve #2?
- To reset the gauge to atmospheric pressure for an accurate differential reading (Correct answer)
- To allow downstream pressure to enter the gauge freely
- To confirm test cock #4 is fully open
- To drain residual chlorine from the test hose
Correct answer: To reset the gauge to atmospheric pressure for an accurate differential reading
Bleeding the high-side hose to atmosphere establishes a true reference point so the differential gauge accurately reads the hold pressure across check valve #2.
BAT Backflow Assembly Tester Evaluation & Troubleshooting 2
During a RP assembly test, the differential pressure across check valve #1 drops below the minimum threshold.
What is the correct next step?