If the drain is directly behind the garage, then a 32mm pipe running the shortest distance outside will be the most practical solution.
If you want to make a failsafe version with respect to condense freezing, get your installer to fit an open tee in the garage, so that a condense drain blockage will cause the condense water to temporarily dribble into the garage rather than knock out the boiler.
A MkII version could be to put a bucket under the tee, so it catches the condensate! Trouble is, after 5 years of no snow the reason for the bucket will have been long forgotton and you will have used it in the garden!Hi simond, IF I do change my boiler, I intend to definitely have my new one drain into either a pipe/drain/or even inside pipework.Reading the blog on frozen condense pipes is making me dubious of changing, but nowt lasts forever;It blew my lagged outside tap off, forgot to isolate it inside.same wall as boiler, but directly behind it outside._11c.
But really all this condense stuff is a mere irritation, in the old days the early condensers used to drain into a bucket, and the customer had to remember to empty it periodically.
Drains will freeze up but only in extreme weather conditions, and statistically we don't see many days where this will happen if the arrangements are to manufacturer recommendations.
My condense doesn't have a trap and just goes stright outside to an open drain in 20mm hosepipe (as per my boiler manufacturer recommendations). It got to -14C outside and the boiler kept going.
It is fair to say that in my experience, Worcesters tend to freeze up more willingly than the Vaillants and Viessmanns, I can only assume this is due to the way the condense dribbles out. But generally speaking, they have a marginally better reliability record than the other two, so you win some, you lose some.