Fault Finding Chart - Grundfos MQ Serie Instrucciones De Instalación Y Funcionamiento

14. Fault finding chart

Fault
1. The pump does
not start.
2. The pump does
not stop.
3. The pump cuts
out during
operation.
4. The pump
starts and
stops too fre-
quently.
5. The pump
gives electric
shocks.
Cause
a) Insufficient water.
b) Overheating due to excessive
liquid temperature
(above +95 °F/+35 °C).
c) Overheating due to seized-up/
choked-up pump.
d) Too low or too high supply volt-
age.
e) No electricity supply.
f) No water consumption.
g) Shaft is blocked.
h) Pump is in alarm condition.
a) Existing pipework is leaking or
defective.
b) Non-return valve is blocked or
missing.
a) Dry running.
b) Overheating due to excessive
liquid temperature
(above +95 °F/+35 °C).
c) Overheating caused by:
– high ambient temperature
(> 113 °F/45 °C)
– overloaded motor
– seized-up motor/pump.
d) Too low supply voltage.
a) Leakage in suction pipe or air
in water.
b) Too low or too high pressure in
pressure tank.
a) Defective ground connection.
Remedy
Check the water supply/suction
pipe.
Supply cold liquid to the pump.
Contact your pump supplier.
Check the supply voltage and cor-
rect the fault, if possible.
Connect the electricity supply.
Open a tap. Check that the height
between the top point of the dis-
charge pipe and the pump does not
exceed 50 ft.
Rotate the shaft as described in 10.2
Reset the pump by means of the on/
off button. See point 2 in the table of
section 9.1 Control panel.
Repair the pipework.
Clean the valve or fit a new non-
return valve.
Check the water supply/
suction pipe.
Supply cold liquid to the pump.
Contact your pump supplier.
Check the supply voltage and cor-
rect the fault, if possible.
Check the water and the supply/suc-
tion pipe.
Check the pressure in the pressure
tank. See section 6. Operating con-
ditions.
Connect the ground connection to
the pump in accordance with local
regulations.
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