Cla-Val Models 50-01 and 650-01 Pressure Relief Valves are hydraulically operated, pilot-controlled, modulating valves designed to maintain constant upstream pressure within close limits. Model 50-01 is the full port version of the valve. Model 650-01 is the reduced port version of the valve. Both are ideal for pressure relief, pressure sustaining, back pressure, or unloading functions in a by-pass system.

Pressure Sustaining Service: When installed in a line between an upper zone and a lower area of heavy demand, the valve acts to maintain desired upstream pressure to prevent “robbing” of the upper zone. Water in excess of pressure setting is allowed to flow to an area of heavy demand, control is smooth, and pressure regulation is positive.

Pressure Relief Service: This fast opening, slow-closing relief valve provides system protection against high-pressure surges on pump start-up and pump shut down by dissipating the excess pressure to a safe location.