Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to DC Volts 
DHW Demand
Access the X20 connector on the right hand side of the PCB
Disconnect the connector to the fan and make safe
Disconnect the connector to the fan and make safe
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Reset appliance as necessary.
Measure the DC voltage between pin 13 on connector X20 at the PCB to a suitable earth point.
Approximately 20 seconds after the appliance is switched on the voltage should change from 0V DC to approx 22V DC.
Note:
Colour of wires may change but test points remain the same.
Measure the DC voltage between pin 13 on connector X20 at the PCB to a suitable earth point.
Approximately 20 seconds after the appliance is switched on the voltage should change from 0V DC to approx 22V DC.
Note:
Colour of wires may change but test points remain the same.
Isolate as per TOPs P4
and refit as necessary