Grundfos SP-G, Installation And Operating Instructions Manual

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8. Fault finding chart
Fault Cause Remedy
1. The pump does not run. a) The fuses are blown. Replace the blown fuses. If the new ones blow too,
the electric installation and the submersible drop cable
should be checked.
b) The ELCB or the voltage-operated ELCB
has tripped out.
Cut in the circuit breaker.
c) No electricity supply. Contact the electricity supply authorities.
d) The motor starter overload has tripped out. Reset the motor starter overload (automatically or
possibly manually). If it trips out again, check the
voltage. Is the voltage OK, see items e) - h).
e) Motor starter/contactor is defective. Replace the motor starter/contactor.
f) Starter device is defective. Repair/replace the starter device.
g) The control circuit has been interrupted or is
defective.
Check the electric installation.
h) The dry-running protection has cut off the
the electricity supply to the pump, due to low
water level.
Check the water level. If it is OK, check the water level
electrodes/level switch.
i) The pump/submersible drop cable is defec-
tive. Repair/replace the pump/cable.
2. The pump runs but
gives no water.
a) The discharge valve is closed. Open the valve.
b) No water or too low water level in borehole. See item 3 a).
c) The non-return valve is stuck in its shut posi-
tion.
Pull out the pump and clean or replace the valve.
d) The inlet strainer is choked up. Pull out the pump and clean the strainer.
e) The pump is defective. Repair/replace the pump.
3. The pump runs at
reduced capacity.
a) The drawdown is larger than anticipated. Increase the installation depth of the pump, throttle
the pump or replace it by a smaller model to obtain a
smaller capacity.
b) Wrong direction of rotation. See section 4.5.1 Checking of direction of rotation.
c) The valves in the discharge pipe are partly
closed/blocked.
Check and clean/replace the valves, if necessary.
d) The discharge pipe is partly choked by
impurities (ochre).
Clean/replace the discharge pipe.
e) The non-return valve of the pump is partly
blocked.
Pull out the pump and check/replace the valve.
f) The pump and the riser pipe are partly
choked by impurities (ochre). Pull out the pump. Check and clean or replace the
pump, if necessary. Clean the pipes.
g) The pump is defective. Repair/replace the pump.
h) Leakage in the pipework. Check and repair the pipework.
i) The riser pipe is defective. Replace the riser pipe.
4. Frequent starts and
stops.
a) The differential of the pressure switch
between the start and stop pressures is too
small.
Increase the differential. However, the stop pressure
must not exceed the operating pressure of the pres-
sure tank, and the start pressure should be high
enough to ensure sufficient water supply.
b) The water level electrodes or level switches
in the reservoir have not been installed
correctly.
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 automatic devices used. If the
intervals between stop/start cannot be changed via the
automatics, the pump capacity may be reduced by
throttling the discharge valve.
c) The non-return valve is leaking or stuck
half-open.
Pull out the pump and clean/replace the non-return
valve.
d) The volume of air in the pressure/diaphragm
tank is too small.
Adjust the volume of air in the pressure/diaphragm
tank in accordance with its Installation and Operating
Instructions.
e) The pressure/diaphragm tank is too small. Increase the capacity of the pressure/diaphragm tank
by replacing or supplementing with another tank.
f) The diaphragm of the diaphragm tank is
defective. Check the diaphragm tank.