Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Disconnect connector X1 from the pump PCB
Disconnect the plug from the pump
Disconnect the plug from the pump
Measurement:
Measure the resistance of the live and neutral wires from the connector X1 to the pump connector.
Expect continuity / zero resistance on each of the wires.
Also inspect the harness and connectors for good overall condition.
Note:
Either of the pump connectors shown may be fitted as it depends on the make of pump (either Wilo or Grundfos).
Expect continuity / zero resistance on each of the wires.
Also inspect the harness and connectors for good overall condition.
Note:
Either of the pump connectors shown may be fitted as it depends on the make of pump (either Wilo or Grundfos).
Isolate as per TOPs P4
and refit as necessary