Be prepared...
Interestingly, when Corgi introduced the larger dia condensate it did very little to reduce freezing. What it did do however was delay the BLOCKING of the pipework because a 40mm dia pipe has 4 x the capacity of a 20mm dia pipe. The insulation also slowed, by a smidge, the initial freezing but literally by less than ten minutes.
What Corgi never took into account was the circulatory air currents that occur in a larger dia pipe - but we won't go into that
The reasons condensate freezes so readily is because in the UK we do not run our boilers in perm condensing mode. If we did it would be far less of an issue. So, running them as we do we get literal drops of condensate flowing every so often. As drops of water contain virtually zero sensible heat to give up they soon transfer it into the open atmosphere of the pipe. At 4 degs C and below they then give up their even smaller amounts of latent heat and change state to ice and we have the start of a freeze.
The only ways to stop external pipework like this freezing is:
- replace the heat lost to atmosphere via trace heating
- move sufficient volume of water in one go that, ultimately, it simply does not have time to lose its heat before reaching its destination.
Be under no illusion, insulation can NEVER stop freezing all it does is reduce the loss of the contained within the fluid. Unfortunately, corgi did not even know that if you are trying to protect against freezing you cannot leave ANY gaps and that the volume of fluid must be closely enclosed. As I write this I begin to realise that they might have indeed understood and simply played a game with installers to try to be seen to be doing something that they ultimately knew would be ineffective - who knows.
So, in summary, and not withstanding other great advice like protecting plastic pipe against UV by painting (shocking to need to do it in my view), personally I'd look at fitting a condensate pump with an interlock (for the boiler) and I'd run the discharge internally through the back of the cupboards to an internal waste. It would be darned simple and not be seen.
Other than that, I'd still fit the pump but I'd discharge it into some 21mm externally. So long as the boiler interlock with the pump works, I do not believe there will be a problem. Even if the pump failed, you could then do a temp discharge into a plastic drum to be manually emptied every 4 hours so keeping the boiler running at all times
I apologise for my alternative views chaps
