A/C condensate lines

Discussion in 'HVAC Heating & Cooling' started by bounced, Jul 5, 2009.

  1. bounced

    bounced New Member

    Jan 28, 2008

    Happened to notice this down in the crawlspace a few days ago and I've got a few questions for those more knowledgeable since this looks... problematic :p .

    1. The secondary condensate outlet is dripping occasionally, even though I checked the primary line and it is flowing too. Is that unusual? It's probably relevant that the primary line is not perfectly sloped. There's a couple of pipes leading to the septic tank in the way and only about a two inch difference between the height of the outlet and the hole that been drilled to the outside ten feet away. So there's a section that's pretty level and then it slopes upward slightly before heading outside. Do I need to correct the slope? Regardless, should I put a trap on the primary line?

    2. I assume the secondary outlet should have at least a trap on it (there's quite a bit of air blowing out it, needless to say), and probably should be run to the outside too? Obviously, the current drip is rusting the unit and putting moisture in the crawlspace.

    Thanks for any advice!

    x-posted to diychatroom
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Sep 2, 2004
    Retired Systems engineer for defense industry.
    New England
    The secondary drain should only have flow if the primary drain is backed up or blocked. All of the manufacturer's instructions call for a trap on the line that I've seen. Under ideal situations, you'd notice when there was discharge from the secondary and have it trigger some alert so you could figure out what's wrong.

    You really want something like 1/4" per foot slope from the output of the trap you need to install.
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