Set Appliance State:

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

Measurement:

System/Boiler is correctly charged as necessary.
System/Boiler is bled of air.
Ensure adequate mains water supply to appliance.
Gas inlet pressure is correct.
Bypass (internal or external to the boiler) is correctly adjusted as necessary.
Check overheat thermostat reset button.