Fault in bimetals in motor
Yes
Replace defective bimetals (over current
protection?
sensors).
No
Contact service shop.
3. The pump does not stop.
Is the pump able to empty
No
Check:
the station to the stop level?
- for leakage in pipe and/or discharge
connection.
Yes
- that the impeller is not clogged.
WARNING: disconnect power before
checking the impeller.
- the non-return valve(s).
- that the pump has adequate capacity.
Fault in level sensing
Yes
Clean the stop sensor.
equipment?
Check the contactor and holding circuit.
Replace defective items.
No
Stop level set too low.
Yes
Raise the stop level.
No
Contact service shop.
4. The pump starts-stops-starts in rapid sequence
Does the pump start due to
Yes
Check:
backflow which fills sump to
- that the distance between the start and stop
start level again?
levels is not too small.
- the non-return valve(s).
No
- that the riser is not too long without a
non-return valve.
Does the contactor’s self-
Yes
Check:
holding function break?
- contactor connections.
- the voltage in the control circuit in relation
No
to the rated voltage on the coil.
Contact service shop.
5. Pump runs but delivers too little or no water.
Check:
-
direction of rotation pump.
-
that valves are open and intact.
-
that pipes, impeller and strainer are not clogged.
-
that the impeller rotates easily.
-
that the suction lift has not been altered.
-
for leakage in the pump installation.
-
for wear on wear ring, impeller, pump casing/flange, suction bottom, diffuser, disc, diffuser.
See also under “Inspection”.
Do not override the motor protection repeatedly if it has tripped.
