Set Appliance State:

Gas Off
Isolate Mains Power to appliance as per TOPs P4
Please ensure the following checks are completed.

Measurement:

System/Boiler is correctly charged as necessary.
System/Boiler is bled of air.
Gas inlet pressure is correct.
Bypass (Internal or External to the Boiler) is correctly adjusted as necessary.
Ensure all manual reset devices are set (Mains Power must be switched off when resetting).