The HSS pilot operated sequence valve is used for very precise sequential (pressure) operation in systems where the amount of flow may vary. It can also be used as a relief valve where back pressure exists in an exhaust line (provided port 3 is connected directly to the reservoir).

The inlet pressure is ported thru orifices in the center of the valve to the pilot relief valve (in the upper portion of the body). When the inlet pressure exceeds this valve's setting, pressure on the top side of the main spool is relieved (thru port 3). A pressure imbalance then exists across the main spool. Port 1 pressure raises the main spool to allow flow to port 2, allowing the operation of a secondary system or flow to drain. Because port 2 is separate from port 3, any back pressure at port 2 does not add to the setting of the pilot valve spring or alter the pressure setting.

Several ranges of adjustable pressure are available.

The HSS cartridge valve is constructed of steel parts, and all operating parts are hardened and ground as required. The cartridge is designed for easy service or field repair.