Wilo Economy - Page 38

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32 WILO SE 10/2010
Pump(s) do not switch off Inlet pressure fluctuates sharply Check inlet pressure, if necessary take
measures to stabilise supply pressure
(e.g. pressure reducer)
Inlet 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
Impellers blocked Check pump, if necessary replace or send
for repair
Non-return valve leaking Check, if necessary replace seal or
replace non-return valve
Non-return valve blocked Check, if necessary remove blockage or
replace non-return valve
Gate valve in system closed or not suffi-
ciently open
Check, open the check valve completely
if necessary
Volume flow too large Check pump data and default values and
correct if necessary
Check valve closed at pressure sensor Inspect, open check valve if necessary
Switch-off pressure set too high Check setting and correct if necessary
Direction of motor rotation false Check the direction of rotation and cor-
rect by changing over the phases if nec-
essary
Switching frequency too high
or fluttering
Inlet pressure fluctuates sharply Check inlet pressure, if necessary take
measures to stabilise supply pressure
(e.g. pressure reducer)
Inlet 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
Check valve closed at pressure sensor Inspect, open check valve if necessary
Supply pressure at diaphragm pressure
vessel incorrect
Check supply pressure and correct if
necessary
Valve on diaphragm pressure vessel
closed
Check valve and open if necessary
Set switching difference too small Check setting and correct if necessary
Fault Cause Remedies