Fault Finding Chart; The Pump Does Not Run; The Pump Runs But Gives No Water; The Pump Runs At Reduced Capacity - Grundfos SQ Series Installation And Operating Instructions Manual

11. Fault finding chart

CAUTION
Electric shock
Minor or moderate personal injury
‐
Before starting any work on the pump/motor, make sure that the power supply has been switched
off and that it cannot be accidentally switched on.

11.1 The pump does not run.

Cause
The fuses in the electric installation are blown.
The ELCB or the voltage-operated ELCB has tripped
out.
No power supply.
The motor protection has cut off the power supply
due to overload.
The pump/submersible drop cable is defective.
Overvoltage or undervoltage has occurred.

11.2 The pump runs but gives no water.

Cause
The discharge valve is closed.
No water or too low water level in borehole.
The non-return valve is stuck in its closed position.
The suction strainer is choked up.
The pump is defective.

11.3 The pump runs at reduced capacity.

Cause
The drawdown is larger than anticipated.
The valves in the discharge pipe are partly closed/
blocked.
The discharge pipe is partly choked by impurities
(ochre).
The non-return valve of the pump is partly blocked.
The pump and the riser pipe are partly choked by
impurities (ochre).
The pump is defective.
Leakage in the pipework.
20
Remedy
Replace the blown fuses. If the new ones blow too, the
electric installation and the submersible drop cable
should be checked.
Cut in the circuit breaker.
Contact the power supply authorities.
Check whether the motor/pump is blocked.
Repair/replace the pump/cable.
Check the power supply.
Remedy
Open the valve.
See item 3 a).
Pull out the pump and clean or replace the valve.
Pull out the pump and clean the strainer.
Repair/replace the pump.
Remedy
Increase the installation depth of the pump, throttle the
pump or replace it by a smaller model to obtain a
smaller capacity.
Check and clean/replace the valves, if necessary.
Clean/replace the discharge pipe.
Pull out the pump and check/replace the valve.
Pull out the pump. Check and clean or replace the
pump, if necessary. Clean the pipes.
Repair/replace the pump.
Check and repair the pipework.