Before You Call – Check These First
Not every boiler fault requires an engineer visit. Some of the most common boiler issues can be resolved in minutes by the homeowner. Run through this checklist before calling out:
1. Check the Boiler Pressure
Look at the pressure gauge on the front of your boiler. It should read between 1 and 1.5 bar. If it's below 1, the boiler may have locked out due to low pressure. You can repressurise the boiler using the filling loop (a flexible braided hose connecting two pipes under the boiler). Turn both valves until the pressure reaches 1.2 bar, then close both valves and reset the boiler.
2. Reset the Boiler
Most modern boilers have a reset button (often a flame symbol, or the boiler may require you to hold a button for 3 seconds). If your boiler has locked out with an error code, note the code and try one reset. If it fires up and stays on, you may have had a one-off fault. If it locks out again, call an engineer.
3. Check the Thermostat and Timer
Make sure your thermostat is set higher than the current room temperature – if the room is warmer than the thermostat setting, the boiler won't fire. Also check that your timer/programmer is set correctly and hasn't been accidentally changed (e.g. after a power cut).
4. Check for a Frozen Condensate Pipe (In Cold Weather)
In winter, the condensate pipe on a condensing boiler (usually a white or grey plastic pipe running down an outside wall to a drain) can freeze. Your boiler may display a specific fault code. If the pipe is accessible, pour warm (not boiling) water over the frozen section and then reset the boiler.
5. Check Your Gas Supply
If your other gas appliances (hob, gas fire) are also not working, you may have a gas supply issue. Check with your energy supplier or try a neighbour. If you smell gas at any point, leave the property immediately and call the National Gas Emergency line on 0800 111 999.
When to Call an Engineer
If none of the above resolves the issue, or the boiler locks out again after resetting, it's time to call an engineer. Make a note of any error codes and the symptoms you've observed – it helps with diagnosis.