5. Fault finding chart
Before removing the terminal box cover, make sure that the electricity supply has been switched off
and that it cannot be accidentally switched on.
Fault
One fuse in the installation is blown.
External mains switch switched off.
The pump does not
Current-/voltage-operated earth-
run.
leakage circuit breaker has tripped
None of the indicator
out.
lights are on.
Missing phase (only three-phase
pumps).
The pump does not
run.
The pump has been stopped by the
The green indicator
external on/off switch.
light flashes.
The pump does not
Rotor blocked, but the pump has not
run.
been cut out by the thermal overload
The green indicator
switch.
light is on.
The pump has been cut out by the
The pump does not
thermal overload switch due to high
run.
liquid temperature or blocked rotor.
The red indicator light
is on.
The green indicator
light is off.
The speed switch module has not
been fitted.
The pump is or has been cut out by
The pump does not
the thermal overload switch and the
run.
external on/off switch is switched off.
The green indicator
light flashes.
The red indicator light
The pump has been stopped by the
is on.
external on/off switch.
The pump will be running with wrong
direction of rotation, if started.
The pump is running.
The pump is running with wrong di-
The red and green in-
rection of rotation (only three-phase
dicator lights are on.
pumps).
Air in the system.
Noise in the system.
The pump flow is too high.
The green indicator
light is on.
The pressure is too high.
Air in the pump.
Noise in the pump.
The green indicator
The inlet pressure is too low.
light is on.
Insufficient heat in
some places in the
The pump performance is too low.
heating system.
6
Cause
Replace the fuse.
Switch on the mains switch.
Repair insulation defects and cut in the circuit
breaker.
Check fuses and connections.
Switch on the external on/off switch.
Switch off the electricity supply and clean/repair
the pump.
Check that the liquid temperature falls within the
specified range.
The pump will restart automatically when it has
cooled to normal temperature.
Note: If the thermal overload switch has cut out
the pump three times within a short period, the
pump must be restarted manually by switching
off the electricity supply.
Switch off the electricity supply by means of the
external mains switch and fit the speed switch
module.
Check that the liquid temperature falls within the
specified range.
Note: If the thermal overload switch has cut out
the pump three times within a short period, the
pump must be restarted manually by switching
off the electricity supply.
Switch off the electricity supply by means of the
external mains switch and interchange two
phases in the terminal box.
Vent the system.
Reduce the pump performance (change to lower
speed).
Reduce the pump performance (change to lower
speed).
Vent the pump.
Increase the inlet pressure and/or check the air
volume in the expansion tank (if installed).
Increase the pump performance (change to
higher speed), if possible, or replace the pump
with a pump with a higher flow.
Remedy