The following are basic troubleshooting scenarios for the reduced pressure principle assembly. They don't represent all situations and may or may not solve any one particular backflow prevention assembly problem in the field.
Note: when replacing internal components, use only factory parts.
Symptom Cause
Relief valve will not open, Leaking #2 shut off valve. gauge does not drop to '0'.
Relief valve will not open, Relief valve stuck gauge drops down to '0'. in closed position.
Relief valve opens when testing Fouled #2 check valve #2 check valve. or disc compression.
Relief valve drips constantly with apparent first check Fouled #1 check valve. reading less than 5 psi.
Relief valve drips constantly with Fouled relief valve. apparent first check reading of 5 psi or higher.