A plumber is performing a routine inspection of a commercial building's backflow prevention assembly, which is an RP (Reduced Pressure) type, serving a chemical mixing station. During the annual test, the plumber observes that the #1 check valve holds tight, but the #2 check valve leaks slightly, and the relief valve discharges intermittently. What is the most appropriate action for the plumber to take next?
- ADisassemble and repair or replace the faulty check valve and relief valve components.
- BReplace the entire RP assembly immediately.
- CIncrease the incoming water pressure to force the #2 check valve to seal.
- DAdjust the spring tension on the relief valve to stop the discharge.
Show answer & explanationAnswer & explanation
Correct answer: A. Disassemble and repair or replace the faulty check valve and relief valve components.
A leaking #2 check valve and intermittently discharging relief valve indicate a failure within the RP assembly, compromising its backflow prevention capability. RP assemblies are designed to be field-testable and repairable. The most appropriate next step is to disassemble, clean, repair, or replace the specific faulty internal components (check valve and relief valve) rather than replacing the entire unit or attempting improper adjustments.
Why the other options are wrong
- B. Replacing the entire assembly is often unnecessary and costly; RP devices are designed for component-level repair.
- C. Increasing pressure is dangerous and will not fix a mechanical leak; it could worsen the problem or damage other components.
- D. Adjusting spring tension without addressing the underlying leak is not a proper repair and could further compromise the device.
RP Backflow Assembly Failure
A Reduced Pressure (RP) backflow assembly failure, indicated by a leaking check valve or discharging relief valve, means the device is not providing proper backflow protection and requires immediate repair or replacement of its internal components by a certified tester/repairer.
- Leaking check valves indicate failure.
- Relief valve discharge indicates failure.
- Requires repair/replacement of internal parts.
- Must be repaired by certified personnel.
Memory trick: RP fails its test, repair the parts, put it to rest.