EB 8039 EN
11
Maintenance
Mounting device
Washer
Spacer used for
disassembly
Spring
Fig. 2:
Mounting device (DN 15 to 80)
Fig. 3:
Alignment of the spring
4. Unthread the clamping bolts of the
mounting device and the plug stem grad-
ually until the plug stem is unscrewed out
of the spring plate (5.6). Remove spring
plate and spring. Unscrew lock nut (3.2).
5.
Remove valve bonnet (5) from valve
body and carefully pull it up, for fail-
close version over the plug stem, and for
fail-open version together with the plug
stem.
6. To replace the seat and the plug in the
fail-close version, unscrew the seat.
To proceed, position the seat wrench (see
Table 2) on the seat so that its recesses
are aligned with the cams of the seat.
Guide the seat wrench over the plug
stem in the fail-close version. Observe
tightening torque according to Table 3.
Insert the guide part of the seat wrench
into the body and unscrew seat with a
suitable tool extension.
7. Carefully clean all parts. Remove gasket
(1.2). If the packing leaks, unscrew the
threaded bushing (5.2) in the valve bon
-
net and pull out the individual parts, e.g.
V-ring packing (4.2), washer (4.3), and
spring (4.1). When replacing the plug,
renew the packing rings (4.2) as well.
Carefully clean all parts and the packing
chamber.
Summary of Contents for 3351
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