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replace every second cover screw with a 5/
16-18 x 3 in. bolt.
7. Continue sequentially loosening all bolts/screws until
all original (short) bolts/screws are disengaged.
until no more spring load exists. Remove bolts, cover,
and diaphragm.
REPLACE DIAPHRAGM
1.
Fit new diaphragm over Actuator cup. Position cover
over diaphragm,
2.
Reinstall Actuator cover following procedure in
REMOVE ACTUATOR COVER in reverse order.
NOTE: In some cases, cup and diaphragm will be
forced above top of frame. As cover is
tightened, check that diaphragm bead is
properly positioned in its retention groove.
3'
spring cup to new diaphragm. Cup must be centered
in hole of Actuator cover.
4.
Reassemble feedback spring and Relay/positioner.
Make certain that each end of spring is located in a
spring cup (one end on diaphragm and the other end
in Relay/positioner) before screwing Relay/
positioner back into position.
Reinstall air lines and restore system to service.
D, F REVERSE-ACTING ACTUATORS
Reverse-acting Actuators are not subject to high internal
spring loads. Therefore, the Actuator cover can be removed
routinely.
Replace diaphragm and sleeve (inner seal) together. Use
SERVICELINE Kit 14003 124-002 for all Actuators. Parts
are rated at 250F (121C).
When using the following procedure, see Figures 9 and
11 for exploded diagrams and Tables 7 and 9 for parts.
Disconnect all air lines, including any connected to
Gradutrol Relay or positive positioner, if present.
Remove cover screws, cover (on MP953B and F,
Relay/positioner remains attached to cover),
feedback spring (MP953B, F), large nut,
lockwasher, cup, and diaphragm.
Remove small sleeve cup, screws, ring, and sleeve
diaphragm.
Install new sleeve diaphragm, checking for proper
seating in its locating groove.
75-5500
5.
Reinstall small sleeve cup, ring, and screws.
6.
Install new main diaphragm, checking that it is
properly located.
7.
Reinstall cup, lockwasher, and nut. Tighten nut
enough to seal diaphragm against cup.
8.
Reinstall feedback spring. Check that spring is
securely seated in grooves on lever and cup support.
9.
Reinstall cover and cover screws.
10.
Reinstall air lines and restore system to service,
REPLACE ACTUATOR BASE
When using the following procedure, see Figures 8 and
10 for exploded diagrams and Tables 6 and
A
Use extreme caution when disassembling Actuators.
Actuator assemblies are under spring load which can reach
550 pounds.
1.
To eliminate internal forces in Actuator assembly and
remove Actuator cover, refer to REMOVE
ACTUATOR COVER under MP953A, C, E
DIRECT-ACTING ACTUATORS in REPLACE
2.
Remove Actuator cup, spring, retainer, plate,
mainspring, and ring (5-in. models only).
3.
Remove fasteners securing base to frame.
4
Install new base assembly and reinstall fasteners.
5.
Reassemble Actuator assembly by following
procedure in Steps 1 and 2 in reverse order.
6.
Reinstall air lines and restore system to service.
When using the following procedure, see Figures 9 and
A
To safely disassemble and reassemble reverse-acting
Actuators with 8 psi start point, a mechanical advantage is
required due to the high compression of the main spring
(200 pounds). For safety, use a large bench vise or C-clamp
and two blocks of wood.
1. To release support assembly from Actuator cup, refer
to Steps 1 through 3 in MP953B, D, F REVERSE-
ACTING ACTUATORS under REPLACE MAIN
DIAPHRAGM.
10
8
for parts.
A
WARNING
A
WARNING
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