Find the condensate pipe. It is usually made of white plastic. If it is outdoors it’ll be fixed to a wall emptying into a drainage system or soakaway. If the pipe is indoors it will be underneath your boiler.
When your boiler is operating correctly it produces water as a by-product known as “Condensate”. It is removed from your boiler by the condensate pipe. In cold weather it’s possible for this pipe to freeze. Stopping your boiler working.
Your boiler might make a gurgling sound or show an error code if it has a digital display. There is usually no need to worry. You can easily defrost a frozen condensate pipe yourself.
If the pipe has been defrosted, it will start normally.
There are steps you can take to prevent freezing again.