Identify the condensate pipe

• It is a white or black plastic pipe running from your boiler to outside, usually to a drain.
• The external section is most likely to freeze.

Look for signs of Freezing

• Boiler not working or showing an error code for example F28, L2, EA.
• Gurgling sounds or visible frost on pipe.

Thaw the pipe Safely 

Option 1: Warm Water 

• Pour warm (not boiling) water over the frozen section.
• Repeat until the ice melts

Option 2: Hot Water Bottle / Warm Cloth

• Wrap a hot water bottle or warm towel around the pipe.
• Leave for 15-30 minutes.

Reset Your Boiler

• Once thawed, press the reset button on your boiler.
• It should fire back up after a short delay.

Prevent It From Freezing Again

• Insulate the pipe with foam lagging.
• Keep heating on low during cold spells.
• Ask an engineer to reroute or upgrade the pipe if it's a recurring issue.

Call A Professional If:

• You can't access the pipe.
• You're unsure what to do.
• The boiler still won't restart after thawing.

For further assistance watch this video by Worcester Bosch:

Thaw and Prevent Frozen Condensate Pipes