What to do when your boiler stops working

When your boiler stops working, it's crucial to approach the problem systematically. Begin with initial checks before progressing to more advanced troubleshooting steps.

What Do I Do When My Boiler Stops Working?

Initial Checks

Power Supply

First, confirm your boiler has power. Check if the display panel is lit. Look for tripped switches in your fuse box, particularly after power cuts or storms. If other appliances work but your boiler doesn't, your boiler's fuse may need attention.

Gas Supply

Verify your gas supply works. Check if other gas appliances function normally. A working gas hob confirms gas reaches your property. If no gas appliances work, contact your gas supplier - there might be a local supply issue or payment needs attention.

Pressure Levels

Modern boilers typically require pressure between 1 and 2 bar. Lower pressure often causes boilers to shut down. Check the pressure gauge on your boiler's front panel. If it's below 1 bar, low pressure might cause your problem.

If your pressure reads below 1 bar, you may need to repressurise your system:

Find the filling loop - usually a silver flexible pipe beneath your boiler
Turn both ends slowly until the pressure gauge shows 1.5 bar
Close both valves fully Watch the pressure - if it drops again quickly, there is a chance there is a leak present.

Frozen Condensate Pipe

During cold weather, condensate pipes can freeze, triggering a boiler shutdown. This plastic pipe leads outside your house. If temperatures drop recently, a frozen condensate pipe might cause your issue.

How to fix a frozen condensate pipe:

Pour warm (not boiling) water over the external pipe section
Reset your boiler once the pipe thaws
Consider pipe insulation to prevent future freezing

How to troubleshoot your boiler

Circulator Pump

Locate the circulator pump and check if it's running. It should feel warm to the touch when operational. If it's cool, inspect for tripped switches or electrical issues. A faulty circulator pump can prevent hot water from circulating through your heating system.

Motor Temperature

Feel the motor casing. If it's excessively hot, this could indicate mechanical problems. Conversely, if it's cool when the boiler should be running, the issue might lie with the thermostat or circulator relay.

Pilot Light

For older boilers with a pilot light, ensure it's lit. If it's out, follow the manufacturer's instructions to relight it safely. If the pilot light won't stay lit, there may be an issue with the thermocouple or gas valve.

Radiators

Cold radiators often indicate trapped air. Turn off your heating system and wait for the radiators to cool completely. Open radiator bleed valves one at a time, closing each valve when water appears. Remember to check boiler pressure afterwards, as bleeding radiators can lower system pressure.

Thermostats

Thermostat issues can often appear as boiler problems. Ensure your thermostat is on and set above room temperature. If the display looks faint, the batteries might need replacement. Check time and program settings are correct. Test the system by raising the temperature significantly above room temperature.

Contact a Gas Safe registered engineer immediately if you notice gas smells, see black marks around the boiler, observe yellow flames instead of blue, experience frequent shutdowns, hear unusual noises, or find leaking water. These symptoms indicate potentially serious issues requiring professional attention.