Immergas Kettling / Boiling in Heat Exchanger

Water heater makes loud banging or knocking noises when heating.

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 buildup in primary heat exchanger, Air in primary circuit, Poor circulation due to weak pump

Safety: Switch off power and allow the unit to cool before bleeding or descaling.

Bleed air: Open automatic and manual air vents to remove trapped air.
Check pump operation: Ensure the circulation pump runs smoothly and quietly.
Descale primary heat exchanger: Have a technician connect a descaling pump and circulate descaling solution through the primary circuit to remove limescale.

Warning: Persistent kettling can damage the heat exchanger; do not ignore loud boiling noises.

Hard 4/5

Primary Heat Exchanger

Check Price on Amazon

We may earn a commission from links on this page.