The RP, High Hazard Backflow Preventer protects against Back Pressure and Back Siphonage. The RP Can not be installed below grade. It must be installed 12" above grade. If the RP is installed inside a building it must have an air gap drain connected to a floor drain. When Testing the RP with gauges the tester is looking for the first check valve to hold above 5.0 PSI, 2nd Check to close tight above the relief valve opening point, and the relief valve to open above 2.0 PSI
Read MoreThe DC, Double Check Valve Assembly, Low Hazard Preventer protects against Back Pressure and Back Siphonage. The DC can be installed below grade with appropriate drainage and space to test and repair the assembly. When testing the DC with gauges, the tester is looking for both check valves to hold tight above 1.0 PSI
Read MoreThe PVB/SVB, Pressure Vacuum Breaker, High Hazard, Protects against Back Siphonage NOT Back Pressure. The PVB must be installed 12" above all down stream piping, heads, and emitters. When testing the Pressure Vacuum Breaker with gauges the tester is looking for the air inlet to open to the atmosphere at above 1.0 PSI. The Second test is the check valve that must hold tight above 1.0 PSI. The SVB is similar in testing but with only one test cock, and the order of the test of the air inlet and check valve is reversed. The vent screw is used instead of draining the test cock.
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