If your radiators are making strange sounds, you’re not alone. Homeowners across Bordon, Whitehill, Liphook, Alton and Farnham often notice banging, gurgling or kettling noises when the heating comes on. The good news is that many of these issues have simple explanations and even simpler fixes.
What your radiator noises are trying to tell you
Radiators and pipework naturally expand as they heat up, but continuous or loud noises usually point to trapped air, limescale build-up, restricted flow or unsecured pipework. Understanding which sound you’re hearing is the first step to putting it right.
Quick checks you can do now
Before diving into more detailed troubleshooting, here are a few quick things worth checking:
- Are all radiator valves fully open?
- Is the boiler pressure between 1 and 1.5 bar when cold?
- Do any radiators feel cold at the top but warm at the bottom?
- Can you hear water trickling or air hissing?
These simple checks often reveal issues you can sort out within minutes.
Radiator banging noise: common causes
A radiator banging noise is one of the most common complaints we hear from customers across GU35, GU34 and GU9. It usually comes from sudden pressure changes or movement within the pipework.
- Pipe expansion against timber: Pipes expanding tightly through floors or joists can cause loud bangs or knocks as the metal rubs.
- Sludge or restricted flow: Debris in the system can create pressure surges, resulting in sharp banging noises.
- Rapid temperature changes: When hot water hits cold metal quickly, it can create a sudden clicking or knocking.
Most of these are harmless but noisy. The fixes below often restore peace quickly.
Gurgling noises and what they mean
Gurgling usually means air is trapped in your radiator. This air prevents hot water from circulating properly, leaving parts of the radiator cool. Homes in older areas of Bordon and Alton, especially those with traditional pipework layouts, often experience this more frequently.
To bleed a radiator safely, follow this quick checklist:
- Turn the heating off and let the system cool.
- Use a radiator key and hold a cloth underneath.
- Turn the bleed valve slowly until air escapes.
- Close the valve as soon as water starts to flow steadily.
- Recheck boiler pressure afterwards.
Bleeding often solves the problem immediately.
Kettling: the kettle-like bubbling or boiling sound
Kettling sounds like a kettle boiling, often coming from the boiler rather than the radiators. It’s usually caused by limescale build-up on the heat exchanger, which creates hotspots and steam pockets. Homes in harder-water areas around Liphook and Farnham encounter this more often.
- Reduced flow from a partially blocked system
- Scale on internal boiler components
- Sludge restricting circulation
While light kettling may not stop your heating from working, persistent boiling sounds are worth investigating to prevent efficiency loss.
Simple DIY fixes you can safely try
Many radiator noises can be reduced or eliminated with basic at-home steps.
- Bleed your radiators: This removes trapped air and restores even heat distribution.
- Check valve positions: Fully open TRVs or lockshield valves help improve flow and reduce pressure surges.
- Add inhibitor: A system inhibitor slows sludge formation and helps keep your system running quietly.
- Ensure pipes aren’t tightly clipped: Loosening a tight pipe clip can stop expansion bangs.
If you’re unsure, these are simple jobs a Gas Safe engineer can handle during routine servicing.
When it’s time to call a professional
Some issues are better diagnosed with specialist equipment. Persistent kettling, repeated pressure loss, or radiators that don’t heat up even after bleeding can point to deeper problems such as pump wear, sludge build-up or system blockages. In these cases, a powerflush, magnetic filter installation or boiler service may be needed.
Next steps: if the noises persist or you’d like a professional inspection, contact us at (01420) 558993.