Listening to your gas boiler banging can be annoying – and concerning. And you have every right to be both annoyed and concerned. A noisy boiler should be addressed right away. Ignoring this common problem may lead to more costly repairs in the future.
Gas Boiler Banging – What’s the culprit?
The most common culprit here is scale build up. Water contains minerals, and over time, those minerals accumulate at the bottom of the boiler tank, causing hot spots. The water boils rapidly and sends bubbles up the tank. The bubbles then dissipate violently when they reach the top of the tank, producing loud, banging noises.
A noisy boiler is also known as “kettling”, as the limescale blocks water flow and causes the water to boil, steam and expand, just like boiling water in a kettle. This is not something that you should fix on your own. Only a gas safe registered engineer should handle the problem.
Gas Boiler Banging – Other causes
There are a few other things that may be causing boiler noise.
- Water temperature: If the water gets too hot, it can cause similar rapid boiling in the tank, sending bubbles of water to the top of the tank. Lowering the boiler thermostat can solve this problem, although this will also make your home less warm. Check if your thermostat is defective and needs replacing. You can learn how to calibrate a thermostat too.
- Low pressure: If the boiler pressure is too low, the boiler will not get enough water supply. With not enough water supply, the heat will not dissipate fast enough and will cause the water to boil. You can check boiler pressure using the pressure gauge. Learn how to increase boiler pressure.
- Air in the system: Trapped pockets of air can enter the system through faulty valves or breaches in the tank, pipes or connections. The difference in the pressure between these pockets of air and the steam produced by the boiler can cause gas boiler banging noises. You can bleed radiator and boiler valves (learn how to here), but the breach in the system will have to be fixed by a qualified engineer.