English
44 WILO SE 04/2013
Switching frequency too high or flutte-
ring
Inlet pipe incorrectly installed Check inlet pipe, if necessary change
pipe guide
Check valve closed at pressure sensor Inspect, open check valve if necessary
No diaphragm pressure vessel present
(optional or accessory)
Retrofit a diaphragm pressure vessel
Supply pressure at existing diaphragm
pressure vessel incorrect
Check supply pressure and correct if
necessary
Valve on existing diaphragm pressure
vessel closed
Check valve and open if necessary
Existing diaphragm pressure vessel
defective
Check the diaphragm pressure vessel
and replace if necessary
Set switching difference too small Check setting and correct if necessary
Pump(s) not stable and/or make unusual
noises
Major fluctuations in intake pressure Check intake pressure, if necessary take
measures to stabilise supply pressure
(e.g. pressure reducer)
Intake pipe blocked or shut off Check inlet pipe, if necessary remove
blockage or open check valve
Nominal diameter of inlet pipe too small Check the inlet pipe, increase the cross-
section for the inlet pipe if necessary
Inlet pipe incorrectly installed Check inlet pipe, if necessary change
pipe guide
Air in inlet Check, if necessary seal pipe. Vent
pumps
Air in the pump Vent pump, check suction line for leaks
and seal if necessary
Impellers blocked Check pump, if necessary replace or have
repaired
Volume flow too large Check pump data and default values and
correct if necessary
Direction of motor rotation false Check direction of rotation and correct
by changing over phases if necessary
Pump(s) not stable and/or make unusual
noises
Mains voltage: a phase is missing Check fuses, cables and connections
Pump not adequately secured to base
frame
Check fixation, tighten fastening screws
if necessary
Bearing damage Check pump/motor, replace if necessary
or have repaired
Motor or pump get too warm
Air in inlet Check, if necessary seal pipe. Vent
pumps
Gate valve in system closed or not suf-
ficiently open
Check, open the check valve completely
if necessary
Impellers blocked Check pump, if necessary replace or have
repaired
Non-return valve blocked Check, if necessary remove blockage or
replace non-return valve
Check valve closed at pressure sensor Inspect, open check valve if necessary
Switch-off point set too high Check setting and correct if necessary
Bearing damage Check pump/motor, replace if necessary
or have repaired
Turn-to-turn fault in motor Check, if necessary replace motor or
have repaired
Mains voltage: a phase is missing Check fuses, cables and connections
Current consumption too high
Non-return valve leaking Check, if necessary replace seal or
replace non-return valve
Volume flow too large Check pump data and default values and
correct if necessary
Turn-to-turn fault in motor Check, if necessary replace motor or
have repaired
Mains voltage: a phase is missing Check fuses, cables and connections
Motor protection switch triggers
Non-return valve defective Check, if necessary replace non-return
valve
Fault Cause Remedy
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