Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Disconnect plug from return sensor
(Removal of the condensate trap is not necessary but will improve access)
(Removal of the condensate trap is not necessary but will improve access)
Measurement:
Measure the resistance of the harness between the flow sensor connector and the white wires, marked 16.1 and 16.2, on X6 connector.
Note:
The pin closest to the clip on the flow sensor
corresponds to the wire marked 16.2.
Note:
The pin closest to the clip on the flow sensor
corresponds to the wire marked 16.2.
Isolate as per TOPs P4
and refit as necessary