The HSAUR valve is used with a HSP (poppet) valve and a HSC (check) valve to unload the pump and maintain a preset pressure in an accumulator system.

While the accumulator is being charged, the HSAUR valve is in the closed position, the poppet of the HSP valve is balanced and blocks the flow thru the valve, and the HSC check valve opens and allows the pump to deliver fluid to the accumulator and system. When the system and accumulator are fully charged, pressure at port 2 of the HSAUR valve pushes the ball off its seat while pressure at port 1 pushes the pin up against the ball. When the ball is off its seat, the vent port of the HSP valve is open to drain, allowing the poppet valve to open and unloading the pump delivery directly to the reservoir. The differential ratio between the ball seat and the pin diameter dictates the re-seat pressure percentage.

The HSAUR valve should not be used without HSP and HSC valves which must me sized to match the pump delivery.

Several maximum pressure and re-seat pressure ratios are offered in each adjustable spring ratio. The cartridge is constructed of steel parts, and all operating parts are hardened and ground as needed. The cartridge is designed for ease of service and field repair.