Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Attach F.G.A unit to fan pressure test point
Ensure boiler is cool (40°C or cooler)
Boiler On/Off Switch Off
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Boiler On/Off switch On, reset boiler if required.
Operate appliance at maximum output using service mode, press & hold the chimney sweep button until the display shows - -, chimney sweep is now active.
Fan pressure will be negative and should be -5.2 mbar or greater (e.g. -6.5mbar).
Note.
1. Boiler may go to lockout during test, reset as required until test complete.
2. When pressure gauge is removed pressure point cap should be replaced.
3. You have 15 minutes to complete test, after that the boiler will switch back to normal mode, to cancel chimney sweep mode press the chimney sweep button.