Set Appliance State:

Mains Power Off
Gas Off
Isolate Mains Power to appliance as per TOPs P4
Remove the burner assembly from the boiler.

Measurement:


Removing the Burner:
Disconnect the two electrode leads, the gas connection and remove the four screws holding the Gas Rail in place, remove the Gas Rail. Now remove the two screws holding the two burner brackets to the combustion chamber. Carefully ease the burner forward to release it from the rear mounting pins and remove it from the boiler.
Thoroughly inspect the Burner assembly for damage or blockages.