Backpressure Backflow – First Check Valve Tight – Second Check Valve Fouled Open Relief Valve Opened Discharging Constantly or Intermittently
Water will continually discharge from the relief valve if the first and second check valves are both fouled open and the device is in a backflow backpressure condition. If the first and second check valves are fouled opened, the water pressure in the zone is greater than the inlet pressure and the relief valve will open with the assistance of the relief valve spring. The RPZ is still providing protection since the relief valve is discharging water as designed. Water will continue to discharge out of the relief valve as long as there is backpressure and inlet water pressure. If the backpressure stops and there is a demand downstream, the relief valve will stop discharging. Water will not discharge out of the relief valve when the RPZ is in a flow condition.