8
Trouble-shooting
Pump delivers insufficient flow rate
Motor is overloaded
Motor protection switch / thermistor trip device trips the unit
Increased bearing temperature
Leakage at the pump
Excessive leakage at the shaft seal
Vibrations during pump operation
Impermissible rise of temperature inside the pump
Table 8: Trouble-shooting
A B C D E F G H Possible cause
Remedy
2)
X
Pump delivers against an excessively
high discharge pressure.
Re-adjust to duty point.
Check system for impurities.
X
X X Pump and/or piping are not completely
vented or primed.
Vent/prime.
X
Suction line or impeller clogged.
Remove deposits in pump and/or piping.
X
Formation of air pockets in the piping
Alter piping layout.
Fit vent valve.
X
X X Suction head is too high/NPSH
available
(positive suction head) is too low.
Check/alter fluid level.
Increase system pressure.
Fully open shut-off element in the suction
line.
Change suction line if the friction losses in the
suction line are too high.
X
Wrong direction of rotation
Interchange two of the phases of the power
cable.
X
X
Wear of internal pump parts
Replace worn parts by new ones.
X X
X
Pump back pressure lower than specified
in purchase order
Re-adjust to duty point.
In the case of persistent overloading, turn
down impeller.
X
Density or viscosity of fluid handled
higher than stated in purchase order
3)
X
Tie bolts/seal element defective
Fit new seal between volute casing and
discharge cover.
Tighten the bolts.
X
Worn shaft seal
Replace shaft seal.
X
X
Score marks or roughness on shaft
sleeve
Replace shaft sleeve.
Replace shaft seal.
X
Vibrations during pump operation
Correct suction conditions.
Re-balance impeller.
Increase pressure at the pump suction nozzle.
X
X X
Pump warped or sympathetic vibrations
in piping
Check pipeline connections and secure fixing
of pump; if required, reduce distances
between the pipe clamps.
Fix the pipelines using anti-vibration material.
X
Increased axial thrust
3)
Clean balancing holes in the impeller.
Replace casing wear rings.
X
X
Insufficient or excessive quantity of
lubricant or unsuitable lubricant
Top up, reduce or change lubricant.
X X
Motor running on two phases only
Replace the defective fuse.
Check cable connections.
Check the motor winding.
A
B
C
D
E
F
G
H
2)
Pump pressure must be released before attempting to remedy faults on parts which are subjected to pressure.
3)
Contact KSB.
8 Trouble-shooting
28 of 36
Trialine / Trialine Z
