John Rumm wrote:
the_constructor wrote:
The condensate pipe on my combi boiler comes out of the wall and rests
in the hopper of a downpipe but with this rather cold weather that we
have all been having, it has tended to freeze up quite a bit.

When you say 'freeze up' do you mean it does actually block? As in, do
you genuinely have a problem... if not, then if it ain't broke, don't
fix it!

The basin pipes etc don't freeze because the water is dumped down them
in batches rather than a trickle. If you were to leave a tap dripping in
a basin you may find a different result.

Most condensing boilers include a concentrate trap that is also designed
to empty periodically rather than in a continuous stream for the same
reason. The open hopper will cool the passing water faster as well.

I agree with that... plus, if you do have a problem then the best way to
resolve it would be to reroute your condensate pipe so it tees into a
waste pipe *inside* the house. I suppose, arguably, if you do have
'trickling' condensate then as John suggests, this might transfer the
problem to the sink(?) waste pipe instead, however due to its larger
diameter it will certainly be less susceptible.

David