Faults, Causes And Remedies - Wilo ISAR MODH1 Series Installation And Operating Instructions Manual

10 Faults, causes and remedies

Faults, particularly those affecting the pumps or
the control system, must be remedied by Wilo's
customer service or a specialist company
Fault
Display on the control device incorrect
Pump(s) do(es) not start
Pump(s) do not switch off
Cause
No mains voltage
Main switch "OFF"
Water level in break tank too low, i.e.
Low-water level reached
Low water level indicated
Low water switch defective
Shut-off device closed at pressure sensor
Start-up pressure set too high
Fuse defective
Motor protection has triggered
Contactor defective
Turn-to-turn fault in the motor
Major fluctuations of the inlet pressure
Inlet pipe clogged or shut off
Nominal diameter of the inlet pipe too
small
Inlet pipe installed incorrectly
Air in the inlet
Impellers clogged
Non-return valve leaking
Non-return valve clogged
Gate valve in the system closed or not
sufficiently open
Flow rate too high
Shut-off device closed at pressure sensor
Switch-off pressure set too high
Incorrect direction of rotation of the
motors
NOTICE!
The general safety instructions must be observed
during any maintenance or repair work! The instal-
lation and operating instructions of the pumps and
the control device must be observed!
Remedy
Make use of the information from the installa-
tion and operating instructions for
the control device
Check the fuses, cables and connections
Activate the main switch
Check the break tank's inlet valve / supply line
Check the inlet pressure and the level in the
break tank
Check and, if necessary, replace the low water
switch
Check installation and setting and correct as
required
Check and open the shut-off valve if neces-
sary
Check the setting and correct it if necessary
Check fuses and replace if necessary
Check the default values against the pump or
motor data, measure the current values and
correct the setting if necessary. Check the
motor for defects and replace if necessary
Check it and replace it if necessary
Check, if necessary replace motor or have it
repaired
Check the inlet pressure and take measures to
stabilise the inlet pressure if necessary (e.g.
pressure reducers)
Check the inlet pipe and remove the clogging
or open the shut-off valve if necessary
Check the inlet pipe and increase the cross
section of the inlet pipe if necessary
Check the inlet pipe and change the pipe
routing if necessary
Check and shut off the piping and vent the
pumps if necessary
Check the pump and replace it or have it
repaired if necessary
Check and replace the seal or non-return
valve if necessary
Check and remove the clogging or replace the
non-return valve if necessary
Check and open the shut-off valve completely
if necessary
Check the pump data and default values and
correct if necessary
Check and open the shut-off valve if neces-
sary
Check the setting and correct it if necessary
Check direction of rotation and correct by
changing over phases if necessary
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