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OPERATION:

Hayward Relief valves are designed for use in piping systems where over pressure of the system may cause damage or failure to other components, such as filters, gauges, or tanks. As the line pressure in the system increases past the set relief pressure of the valve, the piston starts lifting off the seat. The higher the over pressure, the higher the piston lifts off the seat, the greater the flow rate through the valve. (See Chart) It may be desirable to select a relief valve different in size from that of your piping system, or to install two relief valves in parallel, depending upon your requirements. IS1100RV REV E 8/26/99 ECR 819R

Example: If your system must maintain a maximum working pressure of 35 PSI, and start to relieve pressure at 40 PSI your set pressure is 40 PSI. You would like to pass a minimum of 13 GPM at a maximum of 50 PSI, (10 PSI over pressure). The chart above indicates that a 3/4” relief valve will meet your requirements.

OPERATING TEMPERATURE vs PRESSURE