On Mon, 9 Feb 2009 13:05:55 -0000, "Ian_m"
wrote:

"the_constructor" wrote in message
net...
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.

This got me to thinking.

The basin and bath waste pipes never seem to freeze up and these are
directly into the soil pipe. I assume, rightly or wrongly that this is
because (a) the ubends are inside the house and (b) because of the gasses
inside the soil pipe come up into the waste pipes.

Working on theory (b), would it help if I take the condensate pipe from
the hopper and feed it into the bath waste pipe using a 'T' connection and
reducing plug thereby keeping the open end out of direct contact with the
outside air. I have plenty of drop on the pipe to do this, or should I lag
the pipe, though I don't think lagging is the answer.

Your thoughts as always would be most gratefully appreciated.

My boss had his condensing boiler switched back to a non-condensing, by the
boiler manufacturer, as the condensate pipe run kept on freezing, despite
being the pumped variety. The pipe would block, the boiler flood, which
would immediatly halt, but this repeated happening corroded the inside of
the boiler. Went through 3 boilers in 7 tears, all under warranty, before
switching to non condensing. Apparently a condensing boiler should never
have been fitted in this location, a detached'ish garage, due to having have
a long run of condensate drain pipe. One fix tried was heat tape on the
pipe, but as he found out that was disipating 100W 24/7 and was not pleased
when this was discovered.....

The guy who fixed my combi had a look into installing a condensing
boiler in it's place. The nearest drain was about 3.5 metres away and
he reckoned that was too far for an external run with the risk of
freezing up. He advised fitting another more up to date combi but as
the old one is still going strong after £400 of repairs over 5 years I
think we'll wait until it dies.