• Series D actuators are created by removing the spring return feature from a Series C actuator and inserting a seal plate, providing a double-acting piston.
• Extra power may be obtained for the air fail action by releasing a stored volume of air contained in a separate tank.
• Ancillary equipment comprising a three-way switching valve, lock-up valve and a check valve is required, in addition to the volume tank and pipework.
• The existing positioner must be set for double-action operation.

Specifications