Fault Finding Chart; Disposal - Grundfos Unilift AP35B Notice D'installation Et De Fonctionnement

12. Fault finding chart

Warning
Before starting work on the pump, make sure that the power supply to the pump has been
switched off and that it cannot be accidentally switched on.
Fault
1. Motor does not
start.
2. Motor protection/
thermal relay trips
out after short
time of operation.
3. Pump runs
constantly or
gives insufficient
water.
4. Pump runs but
gives no water.

13. Disposal

This product or parts of it must be disposed of in an
environmentally sound way:
1. Use the public or private waste collection service.
2. If this is not possible, contact the nearest
Grundfos company or service workshop.
Cause
a) No power supply.
b) Motor switched off by float switch.
c) Fuses are blown.
d) Motor protection/thermal relay has
tripped out.
e) Impeller blocked by impurities.
f) Short-circuit in cable or motor.
a) Temperature of pumped liquid too high.
b) Impeller blocked or partly blocked by
impurities.
c) Phase failure.
d) Voltage too low.
e) Overload setting of the motor starter too
low.
a) Pump partly blocked by impurities.
b) Discharge pipe or valve partly blocked by
impurities.
c) Impeller not properly fixed to the shaft.
d) Incorrect setting of float switch.
e) Pump too small for the application.
f) Impeller worn.
a) Pump blocked by impurities.
b) Discharge pipe or non-return valve
blocked by impurities.
c) Impeller not properly fixed to the shaft.
d) Air in pump.
e) Liquid level too low. The suction strainer
is not completely submerged in the
pumped liquid.
f) Float switch does not move freely.
Remedy
Connect the power supply.
Adjust/replace the float switch.
Replace fuses.
Wait until the motor protection trips in
again/reset the relay.
Clean the impeller. See 10.3.
Replace the defective part.
Use another pump type.
Clean the impeller. See 10.3.
Call an electrician.
Call an electrician.
Adjust the setting.
Clean the pump. See 10.3.
Clean the discharge pipe.
Tighten the impeller.
Adjust the float switch setting.
Replace the pump.
Replace the impeller.
Clean the pump. See 10.3.
Clean the discharge pipe.
Tighten the impeller.
Vent the pump and the discharge
pipe.
Submerge the pump in the liquid or
adjust the float switch.
Make the float switch move freely.
Subject to alterations.
11