Hayward PMD and PMS actuators feature heavy-duty, corrosion-resistant construction. These actuators are designed to stand up to most corrosive environments and other harsh conditions without the need for epoxy coatings.Series PMD actuators are air-to-air (double acting) actuators, while the PMS Series are air-to-spring (fail safe) actuators. Air-to-air actuators require air pressure for both actuation cycles, Open and Closed. Air-to-spring actuators have a mechanical spring return unit, enclosed in the actuator housing, that is used to operate one of the actuation cycles, either Open or Closed.
