17
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Fault Cause Solution
Pump runs but no water delivered
Pump is not primed with liquid
Fill the pump with the liquid to be
pumped
The pump, suction or discharge pipes
are blocked by solids in the liquid
being pumped
Clean the pump, suction or discharge
pipe
The foot or check valve is blocked or
has failed
Replace the foot or check valve
The suction pipe leaks Repair or replace the suction pipe
The air is in the suction pipe or pump Remove trapped air from system
Motor operating in wrong direction
(three-phase motor)
Change the direction of rotation
of the motor by reversing motor
connections
The pump capacity is not constant
The pump draws in air or the inlet
pressure is too low
Improve the suction conditions
The pump or the suction side of the
piping system partly blocked by
foreign bodies
Clean the pump or suction pipe
The pump rotates in the wrong
direction when switched off
The foot or the check valve has failed Check and replace check valve
Leakage in the suction pipe Repair or replace the suction pipe
The system’s general protection
cuts in
Short circuit Check electrical system
The frequency of Pump start-up is
too high
Leakage in the foot valve, check valve
or system
Repair or replace the components
Ruptured membrane or no air
pre-charge in surge tank
See relevant instructions in surge
tank’s manual
Vibration and noise
Cavitation
Reduce the required flow or
improve the operating conditions of
the pump (suction conditions, head,
flow resistance, liquid temperature)
Make sure that pump and motor
shafts are properly aligned
Adjust the pump and/or motor shafts
Worn motor bearings Replace the bearings or the motor
Operation with frequency converter
Consult a qualified engineer form the
supplier of the frequency converter
Check vibration and noise damping
devices
Replace vibration & noise dampers,
if worn
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