Piston Valves

Piston models are operated with a larger piston that shifts the spool. This allows you to use lower pilot pressures to shift the valve. Because of the large piston area on the actuator, pilot pressure must be limited to 150 PSI on all models. On body styles 3P and 4P, the piston is larger than the valve, therefore these models require custom subplates and recommended only for replacement in existing applications.
Code Prefixes Description Symbol
PP PP 2-position, friction positioned. Double acting piston actuator on one end. Spool stays in shifted position when pilot pressure is removed. PP
PO PO 2-position, spring returned spool. Spool returns to position "C" when pilot pressure is removed. PO
PY PY 3-position, spring centered. Double acting piston actuator on one end. Spool returns to center position when pilot pressure is removed. PY