Set Appliance State:
Mains Power Off
Gas Off
Set Multimeter to AC Volts 
DHW Preheat selector to MAX position
Ensure appliance is cool
Ensure appliance is cool
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Measure voltage across the live (brown wire) and the neutral (blue wire) connections at the fan.
Expect mains voltage.
Note:
The mains voltage should be present for greater than 5 seconds, if the voltage is not present for at least 5 seconds then select the "mains voltage absent" outcome below.
Expect mains voltage.
Note:
The mains voltage should be present for greater than 5 seconds, if the voltage is not present for at least 5 seconds then select the "mains voltage absent" outcome below.
Isolate as per TOPs P4
and refit as necessary