Troubleshooting
Combi Boiler Making Unusual Noises
Boilers are quiet when healthy — new noises are clues.
A healthy combi boiler runs with a steady, low hum. Banging, whistling (kettling), gurgling or vibrating noises usually indicate trapped air, circulation problems, or limescale building up on the heat exchanger.
Some noises are harmless; others signal a developing fault. A technician can identify the cause and prevent damage to the heat exchanger or pump.
What different noises mean
- Kettling (whistling/rumbling): limescale or sludge on the heat exchanger
- Banging on start-up: delayed ignition or air in the system
- Gurgling: trapped air or low pressure
- Vibrating/humming: failing pump bearings
- Tapping: pipework expanding (often harmless)
This is not a DIY repair
Combi boilers are gas-fired appliances regulated under the BC Safety Standards Act. Opening the unit, touching the gas valve, or working on the flue without a valid BC gas-fitter licence is both unsafe and illegal. Diagnosing the fault is helpful — fixing it should always be left to a certified technician.
Call 778-909-5731Related symptoms & help
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