Heatrae Sadia Kettling / Boiling Noise in Heat Exchanger or Cylinder

Heatrae Sadia water heater makes loud banging or knocking noises when heating.

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

Heavy limescale build-up on heating surfaces, Localised boiling due to poor circulation, Incorrect thermostat setting too high

How to Fix / Troubleshooting

Safety first: Noisy boiling can indicate overheating. Isolate power if you suspect unsafe operation. Allow the system to cool before working on it.

Steps to reduce noise:

  • 1. Check thermostat setting: Ensure immersion or control thermostat is set to around 60°C, not at maximum.
  • 2. Descale immersion or heat exchanger: Drain the cylinder or heater as required. Remove the immersion heater or heat exchanger and descale using an appropriate descaling solution, or replace if scale is severe.
  • 3. Check circulation (if indirect): On indirect cylinders, ensure the primary pump is working and that there is no airlock in the primary circuit.
  • 4. Refill and vent: After reassembly, refill the system, vent air, and test for quieter operation.
Advertisements

Repair Difficulty

Hard 4/5

Required Part

Immersion Heater / Heat Exchanger
Check Price on Amazon

We may earn a commission from links on this page.

Advertisements