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10. Fault finding
Fault
1. The pump does not run.
2. The pump runs but gives
no water.
3. The pump runs at
reduced performance.
4. Frequent starts and
stops.
Cause
a) The fuses are blown.
b) The ELCB or the voltage-operated ELCB
has tripped.
c) No power supply.
d) The motor-protective circuit breaker has
tripped.
e) The motor-protective circuit
breaker/contactor is defective.
f)
Starter device is defective.
g) The control circuit has been interrupted or is
defective.
h) The dry-running protection has cut off the
power supply to the pump due to low water
level.
i)
The pump/submersible drop cable is
defective.
a) The discharge valve is closed.
b) No water or too low water level in borehole.
c) The non-return valve is stuck in closed
position.
d) The suction strainer is blocked.
e) The pump is defective.
a) The drawdown is larger than anticipated.
b) Wrong direction of rotation.
c) The valves in the discharge pipe are partly
closed/blocked.
d) The discharge pipe is partly blocked by
impurities (ochre).
e) The non-return valve of the pump is partly
blocked.
f)
The pump and the riser pipe are partly
blocked by impurities (ochre).
g) The pump is defective.
h) Leakage in the pipework.
i)
The riser pipe is defective.
a) The differential of the pressure switch
between the start and stop pressures is too
small.
b) The water level electrodes or level switches
in the reservoir have not been installed
correctly.
c) The non-return valve is leaking or stuck
half-open.
d) The tank precharge pressure is too small.
e) The tank is too small.
f)
The diaphragm of the tank is defective.
Remedy
Replace the blown fuses. If the new ones blow too,
check the electric installation and the submersible drop
cable.
Cut in the circuit breaker.
Contact the power supply company.
Reset the motor-protective circuit breaker
(automatically or possibly manually).
Check the voltage if it trips again. If the voltage is okay,
see items 1e to 1h.
Replace the motor-protective circuit breaker/contactor.
Repair or replace the starter device.
Check the electric installation.
Check the water level. If it is okay, check the water
level electrodes/level switch.
Repair or replace the pump/cable.
Open the valve.
See item 3a.
Pull out the pump and clean or replace the valve.
Pull out the pump and clean the strainer.
Repair or replace the pump.
Increase the installation depth of the pump, throttle the
pump or install a pump with a smaller performance.
See section 6.7.1 Checking the direction of rotation.
Clean or replace the valves.
Clean or replace the pipe.
Pull out the pump and clean or replace the valve.
Pull out the pump and clean or replace it.
Clean the pipes.
Repair or replace the pump.
Check and repair the pipework.
Replace the pipe.
Increase the differential. The stop pressure must not
exceed the operating pressure of the pressure tank,
and the start pressure should be high enough to
ensure sufficient water supply.
Adjust the intervals of the electrodes/level switches to
ensure suitable time between the cutting-in and
cutting-out of the pump. See installation and operating
instructions for the electrodes/level switches. If the
intervals between stop/start cannot be changed via the
automatics, the pump performance may be reduced by
throttling the discharge valve.
Pull out the pump and clean or replace the valve.
Adjust the tank precharge pressure in accordance with
its installation and operating instructions.
Increase the capacity of the tank by replacing or
supplementing with another tank.
Check the diaphragm tank.
15
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