Fault Finding - Grundfos MQ-Serie Montage- Und Betriebsanleitung

9. Fault finding

Fault
1. The pump does
not start.
2. The pump does
not stop.
3. The pump cuts
out during
operation.
4. The pump cuts
out during
operation.
The "Alarm"
indicator light
flashes.
5. The pump starts
and stops too
frequently.
6. The pump gives
electric shocks.
7. The pump starts
when no water is
consumed.
If the pump does not start when the fault has been corrected, contact your pump supplier or Grundfos for
further information.
Cause
a) Insufficient water.
b) Overheating due to excessive liquid
temperature (above +35 °C).
c) Overheating due to
seized-up/choked-up pump.
d) Too low or too high supply voltage.
e) No power supply.
f) No water consumption.
g) The pump is in alarm condition.
a) The existing pipework is leaking or
defective.
b) The non-return valve is blocked or
missing.
a) Dry running.
b) Overheating due to excessive liquid
temperature (above +35 °C).
c) Overheating caused by:
– high ambient temperature (> 45 °C)
– overloaded motor
– seized-up motor/pump.
d) Too low supply voltage.
a) Frequent starts/stops caused by
– leakage in suction pipe
– dripping tap
– running toilet.
a) Leakage in suction pipe or air in the
water.
b) Too low or too high pressure in
pressure tank.
a) Defective earth connection.
a) Defective non-return valve or the
pipework is leaking or defective.
Remedy
Restore the water supply/repair suction
pipe.
Supply cold liquid to the pump.
Contact your pump supplier.
Check the supply voltage and correct the
fault, if possible.
Connect the power supply.
Open a tap. Check that the height
between the top point of the discharge
pipe and the pump does not exceed
15 metres.
Reset the pump by means of the on/off
button. See point 2 in the table in section
5.1 Control panel.
Repair the pipework.
Clean the valve or fit a non-return valve.
Restore the water supply/repair suction
pipe.
Supply cold liquid to the pump.
Contact your pump supplier.
Check the supply voltage and correct the
fault, if possible.
Restore the water supply/repair suction
pipe.
Restore the water supply/repair suction
pipe.
Check pressure in pressure tank.
See section 4.1 Operating conditions.
Connect the earth connection to the pump
in accordance with local regulations.
Repair the non-return valve or the
pipework.
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