What Are The Most Common Causes Of Boiler Breakdowns September 12, 2025 A boiler breakdown can cause real disruption to your daily life, especially during colder months when heating and hot water are essential. While modern boilers are generally reliable, they can still develop faults over time. Understanding the most common causes of breakdowns can help homeowners recognise the early warning signs and know when it is time to call in a professional engineer. Common Reasons Boilers Break Down Boiler faults can vary in severity, but many of the issues engineers see are caused by a handful of common problems. Knowing what these are can help you take action early and avoid more costly repairs. Low Pressure If your boiler pressure drops too low, the system may struggle to heat effectively or shut down completely. This often happens due to small leaks in the system, faulty pressure relief valves, or after bleeding radiators. Low pressure is one of the most common reasons for service call-outs, but it can usually be resolved quickly once the cause is identified. Leaks and Drips Leaks around pipe joints, seals, or inside the boiler itself are another frequent cause of breakdowns. Even a small drip can affect the efficiency of your system and may eventually damage other components. Common culprits include worn seals, corroded parts, or issues with the heat exchanger. If not addressed early, leaks can lead to more serious faults and water damage in the surrounding area. Faulty Ignition or Pilot Light If your boiler cannot ignite properly, it will not produce heat. Faulty pilot lights, ignition leads, or issues with the gas supply can cause this problem. Modern boilers often show an error code when ignition fails, but older models may simply stop working. This is often a straightforward repair for engineers, but it is essential to get it fixed promptly to restore heating and hot water. Thermostat Issues A faulty or inaccurate thermostat can make your home feel colder than it should, even when the boiler itself is functioning. If the thermostat is not communicating correctly with the system, it may result in the heating switching on and off at the wrong times or not heating efficiently. Replacing or recalibrating thermostats can quickly resolve this and restore better control over your heating. Frozen Condensate Pipe In colder weather, the condensate pipe that carries waste water outside can freeze, creating a blockage. When this happens, the boiler may lock out as a safety precaution. This is a very common winter issue, particularly in exposed or poorly insulated pipework. While engineers can resolve the problem quickly, insulation and preventive measures can help stop it happening again in future winters. Limescale Build-Up and Kettling If you hear banging or whistling noises coming from your boiler, it could be kettling. This is caused by a build-up of limescale or sludge in the system, restricting water flow and causing it to overheat. Not only is this noisy, but it can also reduce the efficiency and lifespan of your boiler if left unresolved. Flushing the system or fitting filters can help prevent further damage and keep your boiler running more smoothly. General Wear and Tear Like any appliance, boilers become more prone to faults as they age. Components such as pumps, fans, and valves wear out over time, leading to reduced performance and an increased risk of breakdown. Boilers over 10–15 years old often experience more frequent issues and may eventually need replacing. While repairs can extend their life, at some stage replacement may be more cost-effective. How to Reduce the Risk of Breakdowns While some issues are unavoidable, many boiler breakdowns can be prevented with regular servicing and timely maintenance. Annual checks help engineers spot early signs of leaks, corrosion, or worn parts before they lead to a failure. Cleaning and flushing the system can also reduce limescale build-up, keeping the boiler more efficient. Simple preventive care not only lowers the risk of breakdowns but also extends the lifespan of your boiler. Need a Boiler Repair in Aberdeen, Stonehaven, or Westhill? Westhill Boiler Services provides professional boiler repairs to keep your home safe, warm, and comfortable. Our experienced engineers can quickly diagnose faults, carry out safe repairs, and help prevent further breakdowns. Call us today on 01224548803 or fill out our contact form to book your repair.