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8
Malfunctions
Flange connection ball valve/pipe is leaking
Retighten the flange screws to a tightening torque ac-
cording to Section 1.3. If this does not remedy the
leak, the recommended torques may be exceeded by
10%.
If this also fails to stop the leak, dismantle and inspect
the ball valve.
Dismount and inspect the valve.
Stem passage leaking
With no safety stuffing box:
Dismount valve and repair.
With safety stuffing box:
First of all, the packing gland follower can be tightened.
For torques see Section 1.3.
Then dismount the valve as quickly as possible and
repair.
9
Maintenance
All repair work is to be performed by qualified personnel
using the appropriate tools.
For the arrangement, designation and item numbers of all
parts of the valve, see Section 10.
Spare parts are to be ordered with all the details in acc.
with the valve identification.
Only original spare parts may be installed.
To prevent leaks, a regular check of the connection screws
should be made in line with the operating requirements.
For torques see Section 1.4.
When disassembling and assembling the valve, attention is
to be paid to the tables and drawings in Section 1 and
10.
As the body lining 409 is drawn over the disc/stem unit
221 while warm, this work should only be carried out by
the manufacturer.
Has the pump been shut down, drained and flushed ac-
cording to the regulations?
See also Section 7.3.
If assembled incorrectly, individual components
of the valve may be damaged and this can result
in malfunctions during operation.
9520-022-en
Revision 16
TM 10477
Edition
05/2022
Medium leaking at the partition between lower and upper
halves
Dismont valve and repair, probably the stem seal is not
tight.
Valve does not switch
Has the locking plate been dismounted?
See Section 5.4.
Is the actuator supplied with power?
Has a directional control valve been correctly connect-
ed?
Is there foreign matter in the valve?
The bore of the valve is leaking
Wear at the valve actuation ?
Do limit stops have to be adjusted?
Is the shaft deformed?
Deformation, damage or wear to body lining or disc?
9.1
Notes for assembly
➢ The flexible inlay 521 expands during assembly. Do not
cut off the overhang, but push back into the lower and
upper part of the shell 120.
➢ Before tightening the body screws 914/1 align the
disc/stem unit 221 centrally in the closed position.
➢ Mark the position of the disc/stem unit 221 against
body lining 409 at the hub, so permitting switching on-
ly to this point during later test switching.
➢ With disc/stem unit in closed position, tighten the body
screws (914/1, as well 918/1 and 929/2) until the gap
between the upper and lower part of the shell 120 is
ca. 5 mm.
➢ Open the valve several times counterclockwise (when
viewing the stem unit) and close again in the opposite
direction. A sealing edge can form in this way.
Never switch in the other direction of rotation
over the sealing edge!
➢ Tighten the body bolts 1-2 mm when disc in closed
position.
➢ Repeat the previously described process once or twice.
➢ When finally tightening the body bolts, pay attention to
the torques provided in Section 1.4.
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