Why your boiler
makes noise and when to worry

A boiler always makes some sounds, but some of them tell you something isn't right. Here's how to tell them apart.

Gurgling or bubbling

Usually it means air in the system. It's fixed by bleeding the radiators and the boiler. If it keeps coming back, there may also be a pressure loss to track down.

Banging and hissing

When you hear banging at startup, it's often limescale deposits on the heat exchanger. It's fixed with a cleaning at the service. Ignored, they lower efficiency and shorten the boiler's life.

Noises are the boiler's way of asking for help. They're worth listening to in time.

When to shut the boiler off

If you smell gas, see a yellow flame instead of blue, or the boiler vibrates hard, shut it off and call an authorized plumber. This is not where you experiment.