Backpressure Backflow – First Check Valve Tight – Second Check Valve Fouled Open Relief Valve Opened Discharging Constantly or Intermittently
Water will discharge continuously from the relief valve if the second check valve is fouled open and the device is in a backflow condition. Water will continue to discharge form the relief valve as long as there is backpressure. If the second check valve is fouled open and backpressure exists, the pressure in the zone is greater than the inlet or supply pressure causing the relief valve to open with the assistance of the relief valve spring. The RPZ is providing protection because non-potable water is discharging from the relief valve as designed.