Set Appliance State:
Gas Off
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to AC Volts 
Turn Hot Water Tap On
Selector switch set to CH/DHW position
Boiler DHW thermostat set to MAX
Gain access to fan - right hand side panel may require removal
Boiler DHW thermostat set to MAX
Gain access to fan - right hand side panel may require removal
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Measure the AC voltage between the brown (Live)
and blue (Neutral) terminals on the fan.
Is there a constant mains voltage supply at the fan terminals?
and blue (Neutral) terminals on the fan.
Is there a constant mains voltage supply at the fan terminals?
Isolate as per TOPs P4
and refit as necessary