Common Boiler Issues and How to Prevent Them


Boilers are the heart of our heating systems, especially during the colder months. However, like any essential home appliance, they’re prone to a range of common issues.

Understanding these problems and knowing how to prevent them can save homeowners time, money, and discomfort.

Here are the most frequent boiler issues and tips on how to avoid them:

1. Low Boiler Pressure

Low pressure can cause your heating system to perform poorly. Common indicators include a pressure gauge reading below 1 bar or a central heating system that takes too long to heat up.

This issue can be caused by leaks in the system, recently bled radiators, or a failing pressure relief valve.

Regularly check your boiler’s pressure and check out our blogs on how to re-pressurise your system:

How to Increase Boiler System Pressure

How to Reduce Boiler System Pressure

For persistent issues, contact a professional.

2. No Heat or Hot Water

This could be due to several problems, including broken diaphragms and airlocks, failed motorised valves, issues with your thermostat, or low water levels.

Regular servicing by a Gas Safe registered engineer can help prevent these issues by ensuring all parts are in good working order.

3. Frozen Condensate Pipe

A common issue in the UK’s colder months is the condensate pipe freezing, leading to the boiler shutting down.

To prevent this, insulate your condensate pipe, especially if it’s external to your property. If it does freeze, gently thawing it with warm water can resolve the issue.

4. Kettling

Kettling is caused by limescale or sludge build-up on the boiler’s heat exchanger. This can lead to inefficient operation and increased wear on the boiler.

Installing a water softener or using a descaler can help, as can flushing your system periodically to remove debris.

5. Boiler Keeps Switching Off

This could be due to low water pressure, a blocked condensate pipe, air in the system, or a problem with the thermostat.

Each of these issues has its own specific prevention measures, from maintaining proper pressure to ensuring the condensate pipe is clear and properly insulated.

6. Pilot Light Goes Out

For boilers that still use a pilot light, this issue can be caused by a broken thermocouple, drafts or a buildup of deposit on the pilot light itself.

Ensure your boiler area is draft-free and regularly cleaned.

If the problem persists, it might be time to call in a professional.

7. Radiators Not Heating Up

This often results from air trapped in the system or sludge build-up in the radiators themselves.

Bleeding your radiators can remove trapped air, and flushing the system can clear out sludge. For a guide on how to do this, check out our blog: How to Bleed a Radiator.

Both are effective ways to improve efficiency and heat distribution.

8. Boiler Leaks and Drips

Leaks are usually due to a broken internal component, such as a pump seal or pressure valve.

If you notice leaking water, it’s important to contact a professional immediately to prevent damage to your boiler and your home.

9. Strange Noises

Bangs, whistles, or gurgling sounds can indicate air in the system, low water pressure, or kettling.

Regular maintenance can help prevent these issues by ensuring the system is free of air and debris and that the water pressure is correct.

Check out our blog How to Diagnose Noisy Boiler to help you make simple checks to diagnose a common problem yourself and help to fix any minor boiler issues.

10. Thermostat Issues

If your thermostat is losing accuracy or turning the heating on/off at the wrong times, it may be incorrectly calibrated or nearing the end of its life.

Regular checks and adjustments can prevent these issues, but if problems persist, replacement might be the best solution.

Preventative Measures

The key to preventing common boiler issues lies in regular maintenance and servicing.

An annual check by a Gas Safe registered engineer can identify and resolve minor issues before they become major problems.

Additionally, familiarising yourself with your boiler’s operation manual allows you to understand and rectify common issues promptly.

Remember, while some preventative measures can be undertaken by homeowners, others require the expertise of a professional.

Ensuring your boiler is serviced regularly not only prevents issues but also extends the life of your boiler, ensuring it provides efficient heating for years to come.

Blue Emergency Cover are here to keep your family warm all year round and keep the hot water flowing. Don’t wait for a heating emergency… Get covered today!