Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Remove connector X5 from the main PCB
Gain access to return sensor by removing silencer from fan
Remove the connector from the return sensor
Gain access to return sensor by removing silencer from fan
Remove the connector from the return sensor
Measurement:
Measure the resistance across each wire of the return sensor harness, pins 5 & 6 (black wires) of connector X5 to the return sensor connector.
Expected resistance continuity / zero resistance on each wire.
Note.
1. Ensure a good connection is made or misdiagnosis will occur.
2. Ensure the silencer is correctly re-fitted at the end of the test, turn it clockwise slightly, then fit it over the fan before turning it anti clockwise to lock it in at the top and bottom.
Expected resistance continuity / zero resistance on each wire.
Note.
1. Ensure a good connection is made or misdiagnosis will occur.
2. Ensure the silencer is correctly re-fitted at the end of the test, turn it clockwise slightly, then fit it over the fan before turning it anti clockwise to lock it in at the top and bottom.
Isolate as per TOPs P4
and refit as necessary