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12. Fault finding
DANGER
Electric shock
Death or serious personal injury
‐
Before performing any work on a pump or control
panel, switch off the power supply and lock the
general main switch in position OFF to ensure that the
power supply cannot be accidentally switched on.
For failures relating to the diesel engine or pump, refer to the
specific installation and operating instructions delivered with the
pump set.
12.1 The electric pump does not start
Cause
There is no mains supply.
The general switch is off.
The fuse is defective.
The electrical circuit is
interrupted or defective.
The pump is blocked.
There is an electric motor
failure.
12.2 The diesel pump does not start
Cause
There is no fuel.
There is a battery failure.
There is a diesel engine failure. •
12.3 The thermal relay trips (only for jockey pumps)
Cause
Too much energy consumption
due to defective motor winding.
The pump is under strain.
34
Remedy
•
Connect the power supply.
•
Turn on the general switch.
•
Replace the fuse.
•
Check and repair the
electrical circuit.
•
The hydraulics
are blocked. Dismantle and
clean the pump. See the
installation and operating
instructions of the pump.
•
Repair or replace the electric
motor. See the installation and
operating instructions of the
electric motor.
Remedy
•
Fill the tank.
•
Check the battery and
replace if necessary.
Repair of replace the diesel
engine. See the installation
and operating instructions of
the diesel engine.
Remedy
•
Replace the motor. Contact
Grundfos Service.
•
Dismantle and clean the
pump.
12.4 The flow rate of the pump set is not as desired
Cause
There are air pockets in
the inlet pipe.
The inlet pressure is too low
(cavitation).
The inlet pipe is too narrow.
The pipe is clogged.
The foot valve is clogged or
blocked.
The direction of
rotation is incorrect.
The pump is clogged.
Incorrect flowmeter installation. •
There are air pockets in the
flowmeter.
The measurement flange of the
flowmeter is clogged.
12.5 Water hammer in the system
Cause
Water hammer when the outlet
valves are closed.
Water hammer when the pump
set is stopped.
12.6 Leaks from the mechanical seal
Cause
The mechanical
seal is damaged.
Remedy
•
Replace the inlet pipe or
change its arrangement.
•
Restore the
correct inlet condition.
•
Check the correct sizing of
the inlet pipe.
•
Clean or replace the pipe.
•
Clean or replace the foot
valve.
•
Restore the correct direction
of rotation.
•
Clean the pump. See the
installation and operating
instructions of the pump.
Check and correct
the installation.
•
Bleed air from the flowmeter.
•
Clean the measurement
flange.
Remedy
•
Install additional diaphragm
tanks or a bigger diaphragm
tank.
•
The foot valve closes
late. Replace the foot valve
with a more appropriate
model.
Remedy
•
See the installation and
operating instructions of
the pump.
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