8 Trouble-shooting
51 of 72
0570.81/22-EN
8 Trouble-shooting
WARNING
Improper remedial work on the valve
Risk of injury!
▷
For any work performed in order to remedy faults on the valve observe the
relevant information given in this operating manual and/or the product
literature provided by the accessories manufacturers.
If problems occur that are not described in the following table, consultation with the
KSB service is required.
Table 18:
Trouble-shooting
Problem
Possible cause
Remedy
Leakage at the seat
▪
Contaminations or solids in the
fluid
▪
Erosion, corrosion or abrasion
▪
Excessive loads from pipeline
forces or thermal stresses
1. Dismantle bonnet/cover bolting
902.1/920.1.
2. Rework the seating faces of valve
disc and body using a suitable re-
seating tool.
3. Continue re-seating until the
seating faces exhibit a consistently
smooth and even ring.
Leakage at the gland packing
Unevenly tightened gland packing
1. Re-tighten hexagon nuts 920/920.2
as specified in the manual.
Defective gland packing
1. Undo hexagon nuts 920/920.2.
2. Lift gland follower 452.
3. Clean the gland packing chamber.
4. Insert split packing rings in such a
manner that the cut ends of the
rings are offset by between 120°
and 180°.
Leakage at bonnet/body joint or
cover/body joint (bolted bonnet/
cover design)
Unevenly tightened bonnet/cover
bolts
1. Re-tighten bonnet/cover bolting
902.1/920.1 as specified in the
manual.
Defective bonnet/cover gasket
1. Dismantle bonnet/cover bolting
902.1/920.1.
2. Clean sealing surfaces.
3. Replace joint ring 411.
The tightening torques must be
observed.
Leakage at the bonnet/body joint or
cover/body joint (for pressure seal
design)
Unevenly tightened hexagon head
bolts
1. Re-tighten hexagon head bolts
901.1/920.1 as specified in the
manual.
Defective joint ring
1. Remove pressure seal bonnet/cover.
2. Clean sealing surfaces.
3. Replace joint ring 411.1.
The tightening torques must be
observed.
