(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 2 of 2

Thread: Condensating furnace drain line problem

  1. #1
    DIY Member lemmy's Avatar
    Join Date
    Aug 2013
    knoxville, tn

    Default Condensating furnace drain line problem

    My house unfortunately has a 95% condensating furnace in the attic. The drain line is pvc and has the foam insulation around it. It has a very low slop for about 10' then it turns down and drops 2 stories vertical to the basement where it joins with the condensate line from the unit down there and then goes through the wall to the outside. It runs about 1.5-2' pretty much laying on top of the ground....very little slope. I am worried that I will have freezing problems in the winter and was wanting to make an improvement. These are some ideas I have had:

    1) I have no drains in the basement, but I thought about re-routing the condensate lines in to a condensate pump, then run this up in to the side of a drain pipe just above the trap (like a kitchen sink or shower). Since condensate pumps have check valves, would the condensate pump and basement be protected from a clogged drain causing a back up in to the shower? Are there any other negatives? Should I run this all pvc or pex? What is the best way to attach it to the drain line?

    2) run just the attic unit condensate in to a pump and then run this in to a sewer vent in the attic. I am not really sure this is a good idea. I would think I would need a trap between the pump and the vent, but it seems in the summer that could easily dry up.

    3) dig out the ground near the existing drain line and as soon as the pvc comes out of the wall turn it down 18" and then turn and run it horizontal (with a slop) and fill the area with sand and gravel? The only problem is there isn't much room because this is between the two outside AC units.

    Are there any other better ideas?

    BTW, I live in East TN, so it really doesn't get that cold here, but it isn't unusual to have several days below freezing.

  2. #2
    Forum Admin, Expert Plumber Terry's Avatar
    Join Date
    Aug 2004
    Bothell, Washington
    Blog Entries


    Here is a condensate line running to a trap with primer.

Similar Threads

  1. Dishwasher Odor problem -- Drain line? (PICS included)
    By mrmichaeljmoore in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 10
    Last Post: 08-20-2011, 11:56 AM
  2. Changing oil furnace to 2 line
    By thunderhead in forum HVAC Heating & Cooling
    Replies: 0
    Last Post: 04-05-2009, 03:17 PM
  3. Furnace drain problem
    By dsruss in forum HVAC Heating & Cooling
    Replies: 3
    Last Post: 12-01-2008, 05:23 PM
  4. need to purge a furnace gas line?
    By beezer in forum HVAC Heating & Cooling
    Replies: 2
    Last Post: 09-17-2008, 07:44 PM
  5. How do you stop an airhandler from condensating
    By droemer in forum HVAC Heating & Cooling
    Replies: 7
    Last Post: 09-17-2008, 08:23 AM


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts