If your boiler has started making tapping or knocking sounds, you may be experiencing what heating engineers often refer to as a noisy boiler. Homeowners across Wiltshire often contact us with this issue—whether in Calne, Trowbridge, Chippenham, or Warminster—and the good news is that in most cases, it’s fixable. In this guide, we’ll explain the common causes of boiler noises and safe fixes you can try before calling a professional.
Understanding Why Boilers Make Tapping Noises
Boilers operate by heating water and circulating it through pipework and radiators. When the system is working correctly, it should run quietly. However, several issues can cause tapping, clicking, or knocking sounds. These noises are often early warning signs that something’s not operating efficiently.
Common Causes of Boiler Noises and Safe Fixes
1. Air Trapped in the System
Air pockets in pipes and radiators are one of the most frequent culprits of tapping noises. As water moves past the trapped air, it creates pressure fluctuations that produce knocking sounds. Bleeding your radiators can often solve the problem safely and quickly.
2. Limescale Build-Up (Kettling)
Limescale accumulation inside the heat exchanger restricts water flow and creates “boiling” effects similar to a kettle, producing tapping or bubbling noises. This is especially common in hard water areas like Wiltshire. A full power flush or the addition of a scale reducer may resolve this issue and prevent future damage.
3. Poor Water Pressure
When boiler pressure is too low or too high, it can cause airlocks or flow restrictions. Checking that your system pressure sits between 1 and 1.5 bar (as shown on the pressure gauge) can help quieten the system. If it continues to fluctuate, have it inspected by a Gas Safe engineer.
4. Faulty Pump or Valves
A malfunctioning circulation pump or partially closed valve can cause irregular water flow, resulting in tapping or clunking sounds. A professional engineer can test the pump speed settings and balance the system for safe, quiet operation. If your boiler is a Worcester Bosch model and you suspect a parts issue, we recommend reading our recent blog on Worcester Bosch boiler faults for in-depth troubleshooting advice.
5. Pipe Expansion and Contraction
As your pipes heat up, they expand slightly, and when cooling, they contract. If the pipework is installed too close to joists or walls, this movement can cause tapping. Applying felt or foam insulation between pipes and wall brackets can help reduce the noise safely.
Preventing Boiler Noises in Future
Regular maintenance is the key to preventing recurring noises. Annual servicing keeps components clean, ensures safe pressure levels, and allows minor issues to be resolved before they escalate. Homeowners wanting to understand more about boiler longevity and maintenance options can read our comparison of gas vs oil boiler servicing to determine which system best suits their property.
You might also explore newer energy-efficient systems and renewable options. We’ve written detailed guides such as Monobloc vs Split Heat Pump systems and common heat pump problems to help homeowners make informed choices for quieter, more sustainable heating.
When to Call a Professional Heating Engineer
If your tapping noises persist after basic checks like bleeding radiators or confirming system pressure, it’s best to call a qualified engineer. This ensures safety and compliance with Gas Safe standards. Complex issues, such as pump failures or heat exchanger damage, should never be tackled without professional expertise.
Fixing a Noisy Boiler Safely with A.N. Heating Engineers
Persistent noises can be annoying, but they’re also your heating system’s way of asking for attention. Identifying the common causes of boiler noises and safe fixes early can save you time, money, and stress. Our expert engineers cover Wiltshire and surrounding areas and are trained to handle every type of heating system efficiently.
If your home in Wiltshire has a noisy boiler that’s disrupting your peace, don’t wait for a breakdown—contact our team today for reliable, professional service and long-term solutions.