Noisy boiler causes & fixes

In this blog, our heating engineers in Chesterfield will look at the most typical causes of noisy boilers. We'll look at what causes humming, rattling, and vibrating noises, as well as how limescale accumulation and obstructions may affect the performance of your boiler.

Types of boiler noises and their causes

Banging or Whistling Noises

Boiler kettling occurs when water reaches boiling point inside the boiler, creating steam and pressure issues. This problem is often caused by limescale buildup, incorrect temperature settings, or poor system conditions.

To fix kettling, you should:

check and adjust thermostat settings to ensure they're not set too high,
consider a central heating power flush to remove limescale and debris, and
ensure proper system circulation by checking for blockages in pipes or radiators.

Gurgling Noises

Gurgling noises typically indicate trapped air passing through the system, and moving water in the boiler and radiators. This issue is usually caused by airlocks in the system or radiators.

To resolve gurgling, you should:

bleed the radiators to remove trapped air, starting with the radiator closest to the boiler and working your way through the system, and
ensure the boiler pressure is correct after bleeding the radiators.

Humming or Droning Noises: High Water Pressure

Humming or droning noises often result from water arriving from the mains at too high a pressure. This can be caused by a faulty pump, high boiler pressure, or loose components.

To fix humming or droning, you can:

adjust the pump speed setting if possible,
check and adjust boiler pressure to the manufacturer's recommended level, and
tighten any loose components within the boiler or heating system.

Rattling Noises

Rattling noises typically indicate unsecured parts within the boiler or system, such as loose bolts, unclipped pipes, or open valves.

To fix rattling, you should:

visually inspect the boiler and surrounding pipes for any obvious loose components,
tighten loose bolts using appropriate tools, and
secure any unclipped pipes or open valves.

Vibrating Noises

Vibrating noises can be caused by limescale accumulation or a malfunctioning pump. These issues may also be related to boiler water pressure problems.

To fix vibrating noises, you should:

consider a power flush to remove limescale buildup,
have a qualified engineer replace the pump if it's faulty, and
check and adjust the water pressure to ensure it's within the recommended range.

Remember, if you're unsure about any boiler repairs or maintenance, always consult a Gas Safe registered engineer for professional assistance.