24
EB 8139 EN
Servicing
4. Remove the plug disk (42) and PTFE seal
(28). Thoroughly clean the plug disk.
5. Insert a new PTFE seal (28).
6. Insert the plug disk (42).
7. Tighten the countersunk screw (51) using
a 3 mm screwdriver, while holding the
plug/actuator stem (14) stationary at the
flattened part with an 8 mm open-end
wrench.
8. Insert a new body gasket (31).
9. Screw the valve bonnet (10) with actua-
tor onto the body (1). Observe tightening
torques.
7.2 Replacing the packing
Fail-close (FA)
1.
Position a 26 mm open-end wrench on
the valve bonnet (10) and unscrew the
entire actuator including the valve bonnet
from the body (1).
2. Undo the screws (47) gradually in a
crisscross pattern.
3.
Lift off the actuator housing (2).
4.
Lift off the spring (20).
5. Unscrew the nut (49) from the plug/actu-
ator stem using a socket wrench, while
holding the plug/actuator stem (14) sta-
tionary at the flattened part with an
8 mm open-end wrench.
6. Remove washer (43), piston (3) together
with the piston ring (23) and washer
(46).
7. Remove the O-ring (8.2) and washer
(43) from the plug/actuator stem (14).
8. Unscrew the retaining screw (60) at the
side using a 2 mm hex screwdriver.
9. Unscrew the threaded bushing (11) to-
gether with the actuator base (6) from
the valve bonnet (10) using an 24 mm
open-end wrench.
10. Press the threaded bushing (11) out of
the actuator base (6). Replace the slip
washers (38) with new ones.
11. Pull the actuator/plug stem (14) down
out of the valve bonnet (10).
12. Pull all the packing parts out of the pack-
ing chamber using a suitable tool. Clean
Legend for Fig. 5
1
Body
2
Actuator housing
3
Piston
6
Actuator base
8.2
O-ring
10
Valve bonnet
11
Threaded bushing
14
Plug (with plug/actuator
stem)
20
Spring
21
Compression spring
22
V-ring packing
23
Piston ring
25
Radial shaft seal
31
Body gasket (seal)
33
O-ring
35
O-ring
36
O-ring
38
Washer
43
Washer
44
Washer
46
Spring washer
47
Cap screw
49
Hexagon nut
55
Vent plug
60
Retaining screw
(threaded pin)
66
Filter
S
Signal pressure
connection
