"Classic" Solenoid Valves
"Classic" style solenoid models are assembled for "Internal Pilot" operation; that is, the valves derive shifting pressure for the spool from the valve inlet port. The required pressure to shift the spool is dependent upon the operator style. If the valve must operate at other pressures or vacuum, then the solenoid operator must use an "External Pilot" source at a pressure between 25 PSI to 160 PSI. Valves that require "External Pilot" pressure can be ordered from the factory with the "Z" Option or be converted in the field for "External Pilot" operation.
When using an "External Pilot" source, the maximum pressure of any port is 250 PSI and the maximum vacuum of any port is 28" Hg. A combination of pressure and vacuum on multiple ports is permissible as long as the differential pressure does not exceed 250 PSI.