Raypak Kettling / Boiling in Heat Exchanger

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

Advertisements

Safety Warning

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.

Advertisements

Possible Causes

Lime scale buildup inside Raypak heat exchanger, Low water flow through boiler, Incorrect system pressure, Air trapped in heat exchanger

How to Fix / Troubleshooting

Safety: Turn OFF power and allow the boiler to cool before servicing. Kettling indicates localized boiling and can damage the heat exchanger.

Steps:

  • 1. Check system pressure and flow: Verify pressure is within the recommended range and that all valves are open. Confirm circulator pump operation.
  • 2. Bleed air: Use air vents on or near the boiler to remove trapped air from the heat exchanger and piping.
  • 3. Flush the heat exchanger: For scaled systems, a professional should isolate the Raypak boiler and perform a chemical descaling flush using an approved cleaner and pump.

Persistent kettling usually requires professional cleaning or replacement of the heat exchanger.

Advertisements

Repair Difficulty

Professional Required 5/5

Required Part

Heat Exchanger
Check Price on Amazon

We may earn a commission from links on this page.

Advertisements