A 1/4 in (8 mm) MNPT by 37° male JIC check valve is installed in the pilot actuation port of the primary cylinder valve with direction of flow OUT of the valve. When the valve opens, pressure will be directed through the pilot actuation check valve to the pneumatic valve actuators on the slave cylinders. The purpose of the pilot actuation check valve is to ensure the pneumatic actuator(s) remain pressurized for the entire discharge period.