Grundfos SQ Series User 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 Remedy
The fuses in the electric installation are blown. Replace the blown fuses. If the new ones blow too, the
electric installation and the submersible drop cable
should be checked.
The ELCB or the voltage-operated ELCB has tripped
out.
Cut in the circuit breaker.
No power supply. Contact the power supply authorities.
The motor protection has cut off the power supply
due to overload.
Check whether the motor/pump is blocked.
The pump/submersible drop cable is defective. Repair/replace the pump/cable.
Overvoltage or undervoltage has occurred. Check the power supply.
11.2 The pump runs but gives no water.
Cause Remedy
The discharge valve is closed. Open the valve.
No water or too low water level in borehole. See item 3 a).
The non-return valve is stuck in its closed position. Pull out the pump and clean or replace the valve.
The suction strainer is choked up. Pull out the pump and clean the strainer.
The pump is defective. Repair/replace the pump.
11.3 The pump runs at reduced capacity.
Cause Remedy
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.
The valves in the discharge pipe are partly closed/
blocked.
Check and clean/replace the valves, if necessary.
The discharge pipe is partly choked by impurities
(ochre).
Clean/replace the discharge pipe.
The non-return valve of the pump is partly blocked. Pull out the pump and check/replace the valve.
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.
The pump is defective. Repair/replace the pump.
Leakage in the pipework. Check and repair the pipework.
20
English (GB)

Grundfos SQ Series Specifications

General

Motor	Permanent magnet motor
Material	Stainless steel
Maximum Sand Content	50 g/m³
Protection Class	IP68
Type	Submersible Pump
Power Supply	Single-phase or Three-phase
Installation	Submersible
Pump Diameter	76 mm
Frequency	50 Hz or 60 Hz