Boiler Not Heating? Here’s What to Check January 14, 2026 When your boiler suddenly stops heating your home or hot water, it can quickly become a major inconvenience, especially during colder months. While it’s always best to contact a professional heating engineer for complex issues, there are a few straightforward checks you can perform yourself before making that call. Understanding the possible reasons behind a boiler that’s not heating can also help you explain the problem more clearly when booking boiler repairs in Wigan, Bolton, or Warrington. Common Reasons Your Boiler Stops Heating If your boiler isn’t producing heat, it’s often due to a fault within the heating system, pressure levels, or key internal components. While some issues can be resolved with simple steps, others will require a professional repair to restore your boiler safely and efficiently. Check Your Thermostat Settings Before assuming there’s a serious problem, take a look at your thermostat. It might have been accidentally turned down or switched to a different mode. Ensure the temperature is set higher than the current room temperature and that any timers or schedules are correctly configured. If your thermostat is wireless, check that it’s still connected to the receiver and replace the batteries if needed. Inspect Boiler Pressure Levels Boiler pressure plays a key role in keeping your heating system working properly. If the pressure gauge is showing below 1 bar, the boiler won’t be able to circulate hot water effectively. You can increase the pressure using the filling loop located beneath most boilers, but take care not to overfill it. If the pressure continues to drop after topping up, it could indicate a leak or a failing pressure relief valve, which needs professional attention. Look for Error Codes or Warning Lights Modern boilers are designed with built-in safety systems that shut them down when a fault is detected. The display screen or control panel may show an error code to help identify the cause. For example, codes may relate to ignition failure, low pressure, or sensor errors. Check your boiler manual to interpret these codes or make a note of them before contacting your heating engineer, this can speed up the diagnosis and repair process. Bleed Radiators to Remove Air If your boiler seems to be running but your radiators remain cold or only heat at the bottom, trapped air might be the issue. Using a radiator key, carefully release the air until water begins to escape. This allows the system to circulate heat evenly again, improving comfort and energy efficiency. After bleeding, check your boiler’s pressure, as this process can sometimes cause it to drop slightly. Reset the Boiler In some cases, a boiler may simply need to be reset to clear a minor fault or power surge. Use the reset button following your manufacturer’s guidance, and wait for the boiler to go through its restart cycle. If it locks out again shortly after resetting, there’s likely a deeper problem such as a faulty sensor, diverter valve, or pump that needs to be inspected by a qualified engineer. Internal Component Issues If none of the above checks solve the problem, the issue may lie within one of the boiler’s key internal parts. The pump, which circulates hot water around your heating system, can sometimes seize up. Similarly, the diverter valve may fail to direct hot water correctly between your taps and radiators. Electrical faults with sensors or ignition components can also prevent your boiler from heating. These issues are best left to professionals who can carry out safe and accurate diagnostics. Reliable Boiler Repairs in Wigan, Bolton and Warrington If your boiler isn’t heating up or showing warning signs of a breakdown, TwinSun Heating is here to help. Our experienced engineers provide fast and effective boiler repairs in Wigan, Bolton, and Warrington, restoring your heating system safely and efficiently. We diagnose faults, replace damaged components, and ensure your boiler runs at peak performance all year round. Call us today to arrange a visit or fill out our contact form to book your boiler repair service with our friendly local team.
