Grundfos MQ 3-45 Service Instructions

28.04.2003
GB
14 / 24
4.9 Fault finding
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. Turn on 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 but-
ton. See the table in section 4.7
.
2. The pump does not
stop.
a) The existing pipework is leaking or
defective.
Repair the pipework.
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 starts and
stops too frequently.
a) Leakage in suction pipe or air in the
water.
Check the water supply/suction pipe/O-
rings on the inlet part.
b) Too low or too high pressure in pressure
tank pos. 42.
Check pressure in pressure tank. The pres-
sure must be 1.5 to 1.7 bar.
c) Seized-up or missing non-return valve. Clean the valve or fit a new non-return
valve.
5. The pump gives elec-
tric shocks.
a) Defective earth connection. Connect the earth connection to the pump
in accordance with local regulations.
6. The pumps starts
when no water is con-
sumed.
a) Defective non-return valve or the exist-
ing pipework is leaking or defective.
Clean the valve or fit a new non-return
valve.

Grundfos MQ 3-45 Specifications

General

Power consumption	1000 W
Maximum head	45 m
Maximum flow rate	3 m³/h
Protection class	IP54
Weight	13 kg
Maximum liquid temperature	35 °C
Maximum operating pressure	7.5 bar
Pumped liquid	Clean water
Liquid temperature range	0 - 35 °C
Maximum ambient temperature	45 °C
Supply voltage	220-240 V
Rated power - P2	0.75 kW
Mains frequency	50/60 Hz
Rated current	4.5 A
Enclosure class	IP54
Inlet connection	1 inch
Outlet connection	1 inch
Power supply	220-240 V, 50/60 Hz
Pump type	Centrifugal
Built-in pressure tank	Yes
Approvals	CE
Material	Stainless steel