Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Disconnect the inline connector to the DHW flow switch
Run the hot water tap with a flow rate of 2 l/min
Run the hot water tap with a flow rate of 2 l/min
Measurement:
Measure the resistance between the 2 pins on the connector to the DHW flow switch.
Expect continuity / zero resistance.
Is the resistance measured as expected?
Expect continuity / zero resistance.
Is the resistance measured as expected?
Isolate as per TOPs P4
and refit as necessary