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10. Fault finding
Warning
Before starting any work on the pump, make sure
that the fuses have been removed or the mains
switch has been switched to off. Make sure that
the power supply cannot be accidentally
switched on.
All rotating parts must have stopped moving.
Warning
All regulations applying to submersible
recirculation pumps installed in potentially
explosive environments must be observed.
Make sure that no work is carried out in
potentially explosive environment.
Keep a service log.
Fault
Cause
Remedy
1. The pump does not
start.
a) No power supply or supply failure.
Call an electrician.
b) Supply cable is faulty.
Call an electrician.
c) Control system is faulty.
Call an electrician.
d) Impeller cannot rotate freely.
Clean the impeller and check manually that it can
rotate freely.
e) Stator windings are faulty.
Contact Grundfos.
f)
Motor has cut out because of overheating.
Wait until the motor has cooled and attempt to
restart the pump.
g) Different phase voltages.
Call an electrician.
h) Overload relay is set too low or is faulty.
Check the overload relay. Set the relay to the
rated current. See section
.
i)
Leak sensor has cut out the pump.
Contact Grundfos.
j)
Humidity in motor.
Contact Grundfos.
2. Pump starts, but
stops immediately.
a) Stator windings are faulty.
Contact Grundfos.
b) Different phase voltages.
Call an electrician.
c) Overload relay is set too low or is faulty.
Check the overload relay. Set the relay to the
rated current. See section
.
d) Leak sensor has cut out the pump.
Contact Grundfos.
e) Humidity in motor.
Contact Grundfos.
3. No liquid or
inadequate quantity
is pumped even if the
motor is running.
a) Impeller rotates in the wrong direction.
Interchange two phases of the mains supply.
b) Pump runs on two phases.
1. Check the electrical connections.
2. Replace faulty fuses.
3. Call an electrician.
c) Internal parts are worn.
Contact Grundfos.
d) Impeller dirty or damaged.
Clean the impeller and inspect for any wear.
4. Pump runs unevenly
and makes noise.
a) Internal parts are worn.
Contact Grundfos.
b) Impeller dirty or damaged.
Clean the impeller and inspect for any wear.
c) Faulty motor or gearbox roller bearings.
Contact Grundfos.
d) Oscillations caused by the installation (resonance).
Check installation design.
5. High current and
power consumption.
a) Wrong voltage supply or supply failure.
Call an electrician.
b) Supply cable is faulty.
Call an electrician.
c) Control system is faulty.
Call an electrician.
d) Impeller cannot rotate freely.
Clean the impeller and check manually that it can
rotate freely.
e) Stator windings are faulty.
Contact Grundfos.
f)
Pump runs on two phases.
1. Check the electrical connections.
2. Replace faulty fuses.
3. Call an electrician.
g) Internal parts are worn.
Contact Grundfos.
h) Faulty motor or gearbox roller bearings.
Contact Grundfos.
