The most common call out for a boiler repair in London last Winter for Marvel was due to frozen condense pipes.
Any boiler installed within the last 10 years will have condense pipe like the one in the picture
It’s likely during the winter if you haven’t upgraded to a larger pipe like the black 40mm pipe in this picture- it could freeze …..
so you may have to do this to get you out of trouble….
You can send your pics by clicking here and we can tell you if you need to upgrade your condense run to avoid freezing