Riello Boiler Kettling / Localised Boiling

Boiler makes loud banging or knocking noises (kettling) during operation

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Limescale build-up in primary heat exchanger, Sludge restricting water flow, Incorrect pump speed, Air pockets in heat exchanger

Safety: Kettling indicates overheating in the heat exchanger. Turn off the boiler if noises are severe.

Bleed air: Bleed radiators and any automatic air vents near the boiler to remove trapped air.
Check pump setting: Ensure the circulation pump is running at an adequate speed for the system.
System cleaner: A professional can add a chemical cleaner to the system and flush to remove scale and sludge.
Descale heat exchanger: In hard water areas, the primary heat exchanger may need to be chemically descaled or replaced by a technician.

Hard 4/5

Primary Heat Exchanger

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