31WILO AG 09/2007
English
10. Problems, causes and remedies
CAUTION! Only appropriately trained personnel
must undertake troubleshooting.
Problems Causes Remedies
Output too low Back pressure too high Check the plant for contamination.
Regulate anew the operating point
Pump or pipework, not completely filled Vent and fill the pump as well as the
suction or inflow line
Suction lift too high or positive suction
head too low
Check the liquid level; open the shut-off
valves on the suction side. Clean the fil-
ters
Impeller sealing gap too large Replace worn parts
Wrong direction of rotation Change the motor connection
Pump does not prime or only intermitt-
ently
Pump casing, shaft seal, foot valve or
suction line leaks
Replace the casing seal. Check the shaft
seal. Check the flange connections
Suction lift too high or positive suction
head too low.
Check the liquid level; open the shut-off
valves on the suction side. Clean the fil-
ters on the suction side
Loose or jammed parts in the pump Open and clean the pump
Pump leaks Casing bolts not correctly tightened Check the tightening torque of the
casing boltse
Mechanical seal leaks Check the seal surfaces and rubber
material of the mechanical seal. In case
of damages exchange mechanical seal
Temperature of the pump increases Pump or pipework not completely filled Vent and fill the pump as well as the
suction line or inflow line
Suction lift too high or positive suction
head too low
Check the liquid level; open the shut-off
valves on the suction side. Clean the fil-
ters on the suction side
Pump is run against closed valve Open the shut-off valve on discharge
side
Noisy pump Pump or pipework not completely filled Purge of air the pump and the pipework
Suction lift too high or positive suction
head too low
Check the liquid level; open the shut-off
valves on the suction side. Clean the fil-
ters on the suction side
Pump is not properly levelled or is dis-
torted
Check the pump levelling and alignment
Foreign material in the pump Dismantle and clean the pump
The motor contactor trips Pump is not properly levelled or is dis-
torted
Check the pump levelling and alignment
Earth fault Check the earth connection. Check the
potential causes such as damaged
wirings or cables, leakages on electrical
parts
Operating conditions outside of perfor-
mance range of pump
Refer to pump operating conditions sta-
ted in technical data
Loose or jammed parts in the pump Open and clean the pump
To Next Page
Loading...
