Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
CH Demand
Connect FGA to the combustion test point on the boiler
Ensure CH system is cool
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Check the combustion performance (CO/CO2 ratio), refer to Adapt for guidance / procedure.
Is the combustion performance within the manufacturers specified values?