Boiler makes loud banging or kettling noises during operation

Safety: Noisy boiling can indicate overheating. Do not ignore; it can damage the boiler.

• Check system pressure and flow: Ensure pressure is correct and all valves are open. Bleed radiators to remove air.
• Clean system filter: If fitted, clean the magnetic or dirt filter to improve flow.
• Water treatment: Consider adding a chemical cleaner to the system (following manufacturer instructions) and then flushing. This is best done by a professional.
• Technician tasks: A heating engineer may need to power-flush the system, descale or replace the primary heat exchanger, and verify pump performance.