Normal Operation
757/757DCDA - In normal flowing operation, the independent Link-check remains closed until there is a water demand. Each check will then open and maintain an approximate 1 PSI differential in the direction of flow. In a nonflow or backflow condition, both checks will close until the resumption of normal flow.

957/957RPDA - In normal flowing operation the independent check valves will be open and the pressure differential relief valve located between the two check valves, the area called the zone, will automatically open and close to maintain the zone pressure at least 2 PSI lower than the inlet pressure. If demand for flow stops, the differential pressure relief valve will automatically open and discharge water to maintain the zone at a pressure of 2 PSI lower than the inlet pressure. After the pressure differential is reestablished, the differential pressure relief valve will automatically close.

757/757DCDA	957/957RPDA
Rated Working Pressure 175 PSI	Rated Working Pressure : 175 PSI
Hydrostatic Test Pressure : 350 PSI	Hydrostatic Test Pressure : 350 PSI
Temperature Range : 33 F - 110 F	Temperature Range : 33 F - 110 F
Body Construction : 300 Series Stainless Steel	Body Construction : 300 Series Stainless Steel
End Connection : Groove per AWWA C-606 (IPS) or Flange per ANSI B16.1, Class 125	End Connection : Groove per AWWA C-606 (IPS) or Flange per ANSI B16.1, Class 125

757/957 Series Specification Sheets	Download
757/757N
757a/757Na
757 DCDA/757N DCDA
757a DCDA/757Na DCDA
957/957N/957Z
957 RPDA/957N RPDA/957Z RPDA
757/957 Series Installation Sheets
RP/IS-757/757DCDA
RP/IS-757a/757aDCDA
RP/IS-957/957RPDA