I have now had an opportunity to break down the existing setup and it's going to be a pain if you can't help with sizing advice.

As the saying goes a stitch in time saves 9, and not lagging condensate pipes could lead to a hefty bill to call an engineer out to fix your boiler. The small, white plastic pipe present on the underside of a boiler that usually runs to the outside of your home and ends in the drain is the condensate pipe. It is mostly white in colour and about 20 mm-32 mm in size.This process of producing heat releases carbon dioxide and water vapour which form an acidic wastewater mix called condensate. The condensate is released and sent out of the building through condensate pipes into the drain outside. Where is the condensate pipe on a boiler? In the majority of cases, the boiler will just cease to function, leaving you without any heating during freezing temperatures, literally the worst time to have a boiler breakdown occur!

That being said as long as the pipe isn't leaking and it is in good condition then any kind of pipe insulation can be used but if it's not nitrile rubber or condensate pro but anything other than a closed cell foam lagging, then this will need cladding on the outside to protect it from the elements. Longer lengths of condensate which have many elbows are maybe best left to professional thermal insulation contractors. Where to buy condensate pipe insulation?Therefore for the majority of people nitrile rubber, polyethelene or condensate pro is the easiest and most inexpensive option. How to Install Condensate pipe insulation? By insulating condensate pipes, you can ensure that these pipes do not freeze which gives you a smooth functioning boiler. Not only that, but insulating condensate pipes also reduce the risk of condensation, which in turn prevents the risk of wastewater drips damaging the structure.