110
9. Fault finding chart
If the pump does not start when the fault has been corrected, contact your pump supplier or Grundfos for
further information.
Fault
Cause
Remedy
1. The pump does not
start.
a) Insufficient water.
Check the water supply/suction pipe.
b) Overheating due to excessive liquid
temperature (above +35°C).
Supply cold liquid to the pump.
c) Overheating due to seized-up/
choked-up pump.
Contact your pump supplier.
d) Too low or too high supply voltage.
Check the supply voltage and correct the
fault, if possible.
e) No electricity supply.
Connect the electricity supply.
f) No water consumption.
Open a tap. Check that the height be-
tween the top point of the discharge pipe
and the pump does not exceed 15 metres.
g) The pump is in alarm condition.
Reset the pump by means of the on/off
button. See point 2 in the table in section
4.1 Control panel.
2. The pump does not
stop.
a) The existing pipework is leaking or
defective.
Repair the pipework.
b) The non-return valve is blocked or
missing.
Clean the valve or fit a new non-return
valve.
3. The pump cuts out
during operation.
a) Dry running.
Check the water supply/suction pipe.
b) Overheating due to excessive liquid
temperature (above +35°C).
Supply cold liquid to the pump.
c) Overheating caused by:
- high ambient temperature (> 45°C),
- overloaded motor or
- seized-up motor/pump.
Contact your pump supplier.
d) Too low supply voltage.
Check the supply voltage and correct the
fault, if possible.
4. The pump cuts out
during operation.
The “Alarm” indica-
tor light flashes.
a) Frequent starts/stops caused by
- leakage in suction pipe,
- dripping tap or
- running toilet.
Check the water supply/suction pipe.
5. The pump starts
and stops too fre-
quently.
a) Leakage in suction pipe or air in the
water.
Check the water supply/suction pipe.
b) Too low or too high pressure in pres-
sure tank.
Check pressure in pressure tank, see
section 3.1 Operating conditions.
6. The pump gives
electric shocks.
a) Defective earth connection.
Connect the earth connection to the pump
in accordance with local regulations.
7. The pump starts
when no water is
consumed.
a) Defective non-return valve or the ex-
isting pipework is leaking or defec-
tive.
Clean the valve or fit a new non-return
valve.
Subject to alterations.
Summary of Contents for MQ 3-25
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