Set Appliance State:
Set Multimeter to DC Volts 
Turn Hot Water Tap On
Isolate Mains Power to appliance as per TOPs P4
Gain access to DHW flow switch Molex connector
Gain access to DHW flow switch Molex connector
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Measure the voltage across the green and black wires on the white 3 pin connector to the DHW flow switch.
Expect approx. 2.2 V DC.
Note:
Plug shown disconnected for clarity but should remain connected to the flow switch.
Expect approx. 2.2 V DC.
Note:
Plug shown disconnected for clarity but should remain connected to the flow switch.
Isolate as per TOPs P4
and refit as necessary