I have a customer with a very erratic problem with thier furnace in attic.
Its a Lennox
G43UF-60C-110-08. The problem happens on only extreme cold days. I think
something is freezing or slushing up in the furnace itself, maybe one of the
vac. hoses or drain tubes that lead to the trap.
There were some problems with the furnace drain that I corrected. They had
it draining down an outside wall, uninsulated in some sections, no heat
tape, and they used schedule 80 pipe. I thought for sure when we replaced it
with schedule 40, rerouted it down an inside wall, reinsulated it and put
heat tape on the pipe and trap, that that would solve the problem. But of
course it acted up again, ball buster!!
This attic gets very cold. The water in the bucket I used to drain the pipe
we replaced actually started to freeze. This is one of those green houses
where everything is tight, and very little heat escapes through the ceiling
that would help in this case.
I think the problem is definately somewhere in the furnace with water
freezing. If anyone is familiar with this furnace and this particular
problem, I would appreciate some input.
The temp here in NJ has gone up a little bit in the last couple of days, and
the furnace is working perfect.