During the recent cold snap in the NorthEast we had the drain line from our condenser pump (High Effeciency Furnace) freeze (Just the last inch or so which plugged it) and that meant lots of water inside. There are no drains on that end of the finished basement and running it the 60+ feet to the washing machine isn't really an option.

It is currently run with the air conditioning lines and sticks out 6-8 inches from the wall (the plastic stops at the wall and then it runs into a copper line that is insulated).

Someone mentioned it should actually run next to the exhaust from the furnace that is always warm when running. It would be relatively easy to do but I am always cautious when exhaust gases are involved. The exhaust is a few feet around the corner from the air conditioning unit.

The PVC exhaust vent is probably around 3 feet about ground level.

  • 4
    Perhaps if the line outside were angled downward, it might drain sufficiently to avoid having enough water to form a block.
    – bib
    Commented Jan 14, 2014 at 16:51

2 Answers 2


With my furnace, I diverted the drain line into a 5 gallon bucket which I used to flush toilets. You could install a wye and a valve or two to make the condensate drain into a bucket inside the house on the coldest days. This may be a little too high efficiency, Worked for me. The tricky part is remembering to check the bucket.


I'm not sure if there is a reason (not, probably, a good reason, but all sorts of whacky stuff gets to be code some places) why the pipe would be changed to copper, but if if it's a plastic pipe up to the wall and then a copper pipe, being insulated is going to be of minimal use - it's still an isolated 6-8" hunk of copper out in the cold, and the inside of the pipe isn't insulated and is exposed to the cold. The flow of condensate won't fill the pipe, so a small portion at the bottom will be carrying "warm" condensate, and a large portion of copper pipe will be cold and conducting the heat away from the condensate, freezing it.

I would increase the downward angle (if it's flattish), increase the size of the pipe, and make it plastic. Insulating it is still worth trying, and will also keep the sun off it (one weakness of plastic pipe.)

If there's some code requirement that it be copper, use a longer section of copper, so a couple of feet inside the house can transfer heat to the 6-8" outside the house.

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