English (GB)
5
8. Fault finding the product
DANGER
Electric shock
Death or serious personal injury
- Before removing the terminal box cover and before
removal or dismantling the product, make sure that
the power supply has been switched off and that it
cannot be accidentally switched on.
Fault
Cause
Remedy
1. The motor does not
run when started.
a) Power supply failure.
Reestablish normal power supply.
b) The thermal protection device of the motor has
tripped.
Wait until the motor cools down to allowable
temperature. The motor then restarts.
If the motor still cannot start, contact Grundfos.
c) The product has not been in use for a long
time.
Switch off the power supply and rotate the motor
non-drive end shaft.
d) The motor is defective.
Repair the motor.
2. The product is leaking. a) There is a leakage in the gasket.
Replace the gasket.
b) There is a leakage in the shaft seal.
Replace the shaft seal.
3. The pump capacity is
not constant.
a) The pump inlet pressure is too low.
Increase the liquid level on the inlet side.
Open the isolating valve in the inlet pipe.
b) The inlet pipe or product is partly blocked by
impurities.
Clean the pipeline or product.
c) The product draws in air.
Release the air in the pipeline and product.
4. The product runs but
does not deliver the
rated flow.
a) The inlet pipe or product is blocked by
impurities.
Clean the pipeline or product.
b) The non-return valve is blocked in closed
position.
Clean and open the non-return valve.
c) The direction of rotation is wrong.
Interchange two phases of power supply.
d) There is a leakage in the inlet pipe.
Repair or replace the pipeline.
e) There is air in the inlet pipe or product.
Check the gasket in the pipe connection, make sure
the gasket works.
5. The motor protection
triggers frequently.
a) The power supply is not stable.
Make sure the power supply is stable.
b) The impeller is stuck.
Find the root cause, then repair.
c) The ambient temperature is too high.
Make sure the ambient temperature is within the
normal range: maximum 40 °C.
