British Gas recommends that you contact them to arrange a visit if your condensate pipe is frozen, however here they explain how you can thaw your condensate pipe in these easy steps.
Modern boilers are extremely efficient and produce condensation which runs through your condensate waste pipe.
In extreme weather conditions, your condensate pipe may freeze causing your boiler to shut down.
Step 1 – Find your condensate waste pipe outside.
Step 2 – Place a hot water bottle on the waste pipe where you think it may be frozen.
Another option is to pour water directly onto the waste pipe using something like a watering can. With your boiler out of action, heat the water using your kettle but please DO NOT use boiling water.
Make sure you work at ground level and NEVER disconnect the waste pipe.
To stop freezing in the future you can have a trace heat element installed. These only cost a few pounds a year to run and are extremely efficient. To book an appointment please visit the British Gas website.