Grundfos VersaFlo UPS, Installation And Operating Instructions Manual

Page: 11 / 40

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) One fuse in the installation
is blown.
Replace the fuse.
b) External circuit breaker is
switched off.
Switch the circuit breaker on.
c) Current-/voltage-operated
ground fault interrupter has
tripped.
Repair the insulation defects and reset the
interrupter.
d) The pump's internal thermal
overload switch has cut out
(standard module only) .
Check that the liquid temperature falls within the
specified range.
With external on/off changeover contact:
The pump will restart automatically when it has
cooled to normal temperature.
With external on/off impulse contacts:
The pump can be restarted when it has cooled to
normal temperature.
2. The pump does not
run.
The green indicator
light is on.
a) Rotor blocked, but the
pump hasn't been cut out
by the thermal overload
switch.
Switch off the electrical supply and clean/repair
the pump.
b) The speed switch module
has not been fitted.
Switch off the electrical supply at the external
circuit breaker and fit the speed switch module
into position.
3. Three-phase
pumps only:
The pump is run-
ning.
The red and green
indicator lights are
on.
a) The pump is running with
the wrong direction of
rotation.
Switch off the electrical supply at the external
circuit breaker and interchange any two phases
(leads) in the pump terminal box.
4. 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.
5. 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).
6. Insufficient heat in
some places in the
heating system.
a) The pump performance is
too low.
Increase the pump performance, if possible, or
replace the pump with a pump with higher flow.