Test Procedures Practice Questions

Explanation: Air pockets in hoses create false readings and sluggish gauge response. Bleeding air ensures the hydraulic fluid directly contacts the pressure source and gauge, providing accurate and stable PSID measurements.

Explanation: A 0.7 PSID reading fails the minimum 1.0 PSID requirement for DC check valves. The assembly cannot protect against backpressure and must be removed from service and repaired or replaced.

Explanation: The low side needle valve must be fully closed when recording a reading to obtain the true pressure differential across the check valve. An open low side valve will bleed pressure and provide false low readings.

Explanation: Many jurisdictions commonly require annual calibration so the kit stays within its ±0.2 PSID accuracy. An expired calibration can lead to false pass or fail results and is commonly treated as invalidating test reports.

Explanation: Proper return to service requires closing all test cocks and slowly opening the downstream shutoff while checking for leaks. This confirms the assembly and shutoff valves function correctly in normal operation.

Explanation: RPZ Check Valve #1 is the critical inlet check and must maintain a minimum of 5.0 PSID to protect against dangerous backpressure. This higher requirement reflects its critical role in zone protection.

Explanation: The RPZ relief valve must open at a minimum of 2.0 PSID to maintain the protected zone and protect downstream lines from excessive backpressure. This protects the integrity of the zone between check valves.

Explanation: RPZ Check #1 testing requires high side on test cock #2 (upstream of check) and low side on test cock #3 (in the zone). After bleeding and closing the low side needle valve, the reading must be ≥5.0 PSID.

Explanation: Correct relief valve operation is indicated by visible discharge (water flowing) from the relief valve's vent or drain port while observing the cracking pressure. The pressure gauge indicates the relief opening point.

Explanation: If the relief valve fails to open when test pressure is applied, the valve is either stuck or contaminated and cannot function during a real backpressure event. The assembly must be removed from service and replaced.

Explanation: With the gauge on TC2 (high) and TC3 (low), the bypass hose is connected to TC4 to put supply pressure downstream of check #2. If the reading holds, check #2 is recorded as closed tight; otherwise, as leaked. Some local procedures (such as NEWWA-based ones) also require ≥1.0 PSID, so follow your local procedure.

Explanation: RPZ testing includes an additional critical relief valve test and requires higher PSID minimums (5.0 for Check #1 vs 1.0 for DC). This reflects the RPZ's superior protection against backpressure.

Explanation: Gauge needle fluctuation indicates air pockets in the hoses or an unstable flow. The test must be stopped, hoses bled again, and the reading retaken to ensure accuracy within ±0.2 PSID tolerance.

Explanation: Shutoff #2 must be closed after the preliminary bleed procedure (opening #4 to reduce pressure to 0 PSI). Closing it at the wrong time can trap air or create inaccurate test conditions.

Explanation: Check Valve #1 passes at 1.2 PSID but Check Valve #2 fails at 0.8 PSID (below the 1.0 minimum). An assembly fails if any component fails; the entire assembly must be replaced to restore protection.

Explanation: Test cock #1 is located upstream of the entire assembly and allows measurement of the incoming supply pressure. This verifies that adequate test pressure is available before beginning individual check valve tests.

Explanation: All RPZ test values meet minimums: Check #1 ≥5.0 PSID (passes), Relief ≥2.0 PSID (passes), Check #2 ≥1.0 PSID (passes). The assembly provides adequate backflow protection and is acceptable for service.

Explanation: Shutoff #2 is opened only after testing is complete and all test cocks are closed, allowing the assembly to return to normal service. Opening it during testing would invalidate readings.

Explanation: A DC assembly's two independently acting check valves protect against both backpressure and backsiphonage. Because it has no relief valve, it is approved only for non-health (pollutant) hazards.

Explanation: On return to service, the tester opens shutoff #2 slowly and confirms that the assembly is not leaking from its body, seals or test cocks, and that any RP relief valve is not discharging. Test cocks should be closed and the hoses removed.

Explanation: Continuous relief flow after pressurization indicates the relief valve is not seating properly after discharge. Once the zone is charged to test pressure, the relief should stop flowing and the pressure should hold steady.

Explanation: After testing, close test cocks in reverse order: #4, #3, #2. This ensures safe depressurization and prevents sudden pressure loss. Then the shutoff valve #2 is opened to return the assembly to service.

Explanation: A PVB is designed to prevent backsiphonage, and a 1.0 PSID reading confirms the check valve is sealing properly. This indicates the assembly will function correctly to prevent backsiphonage events.

Explanation: No adjustments to the assembly can be made during testing. If adjustments are made, the entire test must be restarted from the beginning to ensure valid results and proper testing sequence.

Explanation: A stable, constant reading with the low side closed indicates an accurate PSID measurement with the check valve properly sealing. Any drift or decline suggests leakage or air in the hoses.

Explanation: Bleeding to 0 PSI establishes a known baseline and removes any residual pressure from previous use or service. This ensures the first pressure reading is accurate and not inflated by trapped pressure.

Explanation: Zero reading on the low side typically indicates the low side needle valve is still closed or the hose is not connected to a test cock. The technician should verify the low side needle is fully open and hose connections are secure.

Explanation: The proper return to service sequence is: disconnect test equipment, close all test cocks, slowly open shutoff #2, and verify the assembly operates without leaks and relief valve seats properly.

Explanation: ±0.2 PSID is the accuracy a test kit must meet when it is calibrated. A kit outside that tolerance must be repaired or recalibrated. Field readings are judged as read, with no tolerance added or subtracted.

Explanation: When high side supply is 80 PSI and low side reads 78.8 PSI (or similar), the differential of 1.2 PSID across the check valve is what matters. This passes the 1.0 PSID minimum for DC check valves.

Explanation: Shutoff #2 must be fully closed at the start of testing to isolate the assembly from the supply pressure. This is the first step in preliminary procedure and ensures the assembly sits idle during setup.

Explanation: The RPZ relief valve must open at a minimum of 2.0 PSID. A reading of 2.3 PSID exceeds this minimum and indicates proper valve operation and zone protection.

Explanation: Test cock #1, located upstream of the entire assembly, provides the upstream supply pressure. When connected to the high side gauge, it shows the incoming pressure available for testing.

Explanation: Failed assemblies require a detailed report documenting the test results, which specific component failed, and the recommended action (repair, replacement, or further testing). This protects both the technician and property owner.

Explanation: A sudden pressure drop on the high side indicates a disconnected hose, failed connection, or gauge malfunction. The test must be stopped, the issue corrected, and testing restarted from the beginning.

Explanation: After the relief valve opens during testing, pressure should be held steady to observe when the valve closes and reseating occurs. The technician watches for continuous discharge to stop, indicating proper valve function.

Explanation: The relief valve opens at 1.8 PSID, which is below the 2.0 PSID minimum requirement. Even though Check #1 and #2 pass, the relief valve failure means the assembly cannot protect the zone and must be replaced.

Explanation: Check #2 is a second, independent barrier against backflow. On a DC it is tested with the high hose on TC3 and the low hose on TC4, and it must hold at least 1.0 PSID.

Explanation: An SVB uses the same pass criteria as a PVB: the air inlet must open at ≥1.0 psi and open fully, and the check must hold ≥1.0 psid. The hookup differs: the SVB is tested through its single test cock and its vent valve, following the manufacturer's and your program's procedure.

Explanation: Air in the system compresses under pressure and can register falsely high readings. A valve that is actually failing (0.8 PSID) might read 1.1 PSID if air is present, resulting in a false pass.

Explanation: Open the high needle fully, then crack the low needle no more than 1/4 turn so the zone bleeds slowly. Record the differential (supply minus zone) at the first discharge from the relief valve. It must be at least 2.0 PSID.

Explanation: A 2.4 PSID differential well exceeds the 1.0 PSID minimum for DC check valves and indicates excellent seating. Higher differentials are acceptable and indicate strong protection.

Explanation: The high hose goes on TC2 (supply side of check #1) and the low hose on TC3 (zone). With shutoff #2 closed and the high needle open, crack the low needle no more than 1/4 turn to bleed the zone slowly. The differential at the first relief discharge is the opening point, which must be ≥2.0 PSID.

Explanation: Steady relief discharge in service usually means check #1 is fouled. Supply water leaks into the zone and holds it at the relief opening point. A fouled relief valve seat can do the same. The assembly needs repair and a retest.

Explanation: Slowly opening shutoff #2 during return to service verifies the valve operates smoothly and the assembly functions without leaks when full pressure is restored. Any leaks at seals or connections indicate assembly issues.

Explanation: Test cock #1 is located upstream of the entire assembly and measures the incoming supply pressure. This preliminary reading confirms adequate pressure is available to perform the tests.

Explanation: The relief valve (≥2.0 PSID) and check #1 (≥5.0 PSID and above the relief opening point) pass, but check #2 must be recorded as closed tight. A leaking check #2 fails the assembly, which must be repaired and retested. Where your local procedure uses a numeric check #2 criterion (such as ≥1.0 PSID), follow it.

Explanation: A failed test has a clear reading below the minimum requirement. An inconclusive result occurs when gauge malfunction, equipment issues, or procedure errors make the reading unreliable, requiring a retest with confirmed equipment.

Explanation: Leaving test cocks open during return to service could allow water to leak from the assembly and create an unsafe condition. Closed test cocks ensure the assembly operates in normal service mode.

Explanation: A leaking check makes a held differential fall, not rise. A reading that keeps climbing points to pressure changing upstream (supply fluctuations) or downstream (for example, a leaking shutoff #2). Stabilize the conditions before recording a reading.

Explanation: Many jurisdictions commonly require annual test kit calibration. A kit past its calibration date cannot be relied on, and tests made with it are commonly treated as invalid. The kit must be recalibrated before testing resumes.

Explanation: The standardized sequence ensures consistency, eliminates guesswork, and provides documented evidence of assembly performance. Following the exact procedure every time protects the water supply and provides legal documentation.