Pennco Kettling / Boiling in Heat Exchanger

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

Lime scale buildup in cast iron or copper heat exchanger, Low flow through boiler, Incorrect system pressure, Air in heat exchanger

Safety first: Turn off power and allow boiler to cool before touching piping.

Check pressure and flow: Verify system pressure is within range and circulator is running.
Bleed air: Use air vents and purge valves to remove air from the boiler and near-boiler piping.
Water quality: If the system has hard water, consider having a professional perform a chemical descaling of the heat exchanger.
Do not ignore kettling: Persistent kettling can damage the heat exchanger; have a technician evaluate.

Hard 4/5

Boiler Heat Exchanger

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