Your boiler is struggling to process heat correctly, which is causing rattling or banging sounds and suggests internal components are dirty or clogged.

Technical description

1. Heat exchanger scaled. Ultimately this will cause the heat exchanger fins to discolour and buckle. 2. Noisy ignition could be caused by incorrect setting of the slow ignition screw. 3. Reduced pilot rate caused by dirt. 4. Burner aeration ports and main flame ports blocked.