11
5. Troubleshooting
5.1 Fault finding chart
Warning!
Before removing the terminal box cover, make sure that the electrical supply has
been switched off and that it cannot be accidentally switched on.
The pumped liquid may be scalding hot and under high pressure. Before any
removal or dismantling of the pump, the system must be drained or the isolation
valves on both sides of the pump must be closed.
Fault
Cause
Remedy
1. The pump does not
run. None of the
indicator lights are
on.
a) External circuit breaker
is switched off.
Switch the circuit breaker on.
b) Current-/voltage-
operated ground fault
interrupter has tripped.
Repair the insulation defects and reset
the interrupter.
2. The pump does not
run. The green indi-
cator light is on.
a) Rotor is blocked.
Switch off the electrical supply and
clean /repair the pump.
b) The speed switch is not
fully positioned (is
between speeds)
Switch off the electrical supply at the
external circuit breaker and change
speed switch into position.
c) The pump has been cut
out by the thermal
overload switch due to
high liquid temperature.
Check that the liquid temperature falls
within the specified range. The pump
will restart automatically when it has
cooled to normal temperature.
3. Noise in the system.
The green indicator
light is on.
a) Air in the system.
Vent the system.
b) The pump flow is too
high.
Reduce the pump performance.
c) The pressure is too
high.
Reduce the pump performance.
4. Noise in the pump.
The green indicator
light is on.
a) Air in the pump.
Vent the pump.
b) The inlet pressure is
too low.
Increase the inlet pressure and/or check
the air volume in the expansion tank
(if installed).
5. The pump runs, but
the indicator light is
off.
a) The LED diode was
damaged when
installing the terminal
box cover or is burned
out.
Switch off the power and change the
printed circuit board or replace the
complete terminal box.
6. Insufficient heat in
some places in the
heating system.
a) The pump performance
is too low.
Increase the pump performance, if
possible. Flow too fast through the
boiler/heat exchanger may not allow for
the proper BTU transfer to the fluid. If
fluid is too slow, fluid may be cooling too
much before returning from the system.
If changing speeds does not resolve the
problem, replacing the pump with a
properly sized pump may be required.
b) The performance is too
high.
