© 2015 General Electric Company. All right s reserved.
Masoneilan 37-38 Series Actuators Instruction Manual | 5
Air-to-Retract Actuators (Type 38)
Diaphragm Replacement
The procedure is the same as for air-to-extend
actuators except that the entire upper case
assembly (including spring barrel (71), spring (22),
spring seats (33 and 34), nut (30) and diaphragm
plate (40) must be removed to release the
diaphragm. Install a new diaphragm and
reassembly the above parts.
Spring Adjustment
The procedure is identical with that for air-to-
extend actuators except that supply air is piped to
the 1/4" port in the yoke.
Packing Box
The packing box is subject to low air pressure only
and requires minimum maintenance.
The packing rings have a square section and are
made of carbon core with braided PTFE jacket. The
packing may be added to or completely replaced
without disassembling either the actuator or the
mechanism (or valve) to which it is attached. Be
sure to tighten packing nut (20) lightly. Over-
tightening will cause excessive friction, resulting in
sluggish performance.
