Set Appliance State:
Mains Power Off
Gas Off
Set Multimeter to AC Volts 
DHW Preheat selector to MAX position
Selector switch to DHW position
Ensure appliance is cool
Selector switch to DHW position
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