13
Cause Remedy
1)
D
Pump delivers against an excessively high discharge
Re-adjust to duty point.
pressure.
D
Excessively high back pressure.
Check plant for impurities.
D
D D
Pump or piping are not completely vented or primed.
Vent and/or prime.
D
Suction line or impeller clogged
Remove deposits in the pump and/or piping.
D
Formation of air pockets in the piping.
Alter piping layout.
Fit a vent valve.
D
D D
Suction head is too high/NPSH- available
Check/alter liquid level.
(positive suction head) is too low.
Fully open shut-off valve in the suction line.
Change suction line, if the friction losses in the suction line
are too high.
Check any strainers installed/suction opening.
D
Wrong direction of rotation.
Interchange two of the phases of the power supply cable.
D
D
Wear of internal pump parts.
Replace worn components by new ones.
D D
D
Pump back pressure is lower than specified in the purchase
Adjust to duty point.
order.
D
The density or viscosity of the fluid pumped is higher than
2)
specified in the order.
D
Defective gasket
Fit new gasket between volute casing and discharge cover.
D
Worn shaft seal.
Fit new shaft seal.
D
D
Score marks or roughness on shaft sleeve.
Fit new shaft sleeve.
Fit new shaft seal.
D
Vibrations during pump operation
Improve suction conditions.
Increase pressure at the pump suction nozzle.
D
D
D
Pump is warped
Check pipeline connections and secure fixing of pump; if required,
reduce the distances between the pipe clamps.
Fix the pipelines using anti-vibration material.
D
Increased axial thrust.
2)
Clean balancing holes in the impeller.
Fit new wear rings.
D
Insufficient or excessive quantity of lubricant or unsuitable
Top up, reduce or change lubricant.
lubricant.
D D
Motor is running on two phases only.
Replace the defective fuse.
Check the electric cable connections.
D
Rotor is out of balance.
Clean the impeller.
Re-balance the impeller.
D
Defective bearing(s).
Fit new bearings.
D
D Insufficient rate of flow.
Increase the minimum rate of flow.
D
Incorrect setting of motor protection switch
Check setting.
Fit new motor protection switch
D D
Transport lock has not been removed from the shaft groove.
Remove.
1) Pump pressure must be released before attempting to remedy faults on parts which are subjected to pressure.
2) Request particulars.
8 Trouble-shooting
Etabloc
Pump deliv
ers insufficient flo
w r
ate
Motor is o
v
er
loaded
Motor protection s
witch tr
ips the pump
Excessiv
e bear
ing temper
ature
Leakage at the pump
Excessiv
e leakage at the shaft seal
Vibr
ations dur
ing pump oper
ation
Excessiv
e r
ise of temper
ature inside the pump
