New furnace draining into foundation -- overflow

Discussion in 'HVAC Heating & Cooling' started by caleb_tng, Dec 9, 2012.

  1. caleb_tng

    caleb_tng New Member

    Messages:
    5
    Location:
    PA
    Awesome new Trane XV95 furnace, but it is spilling a whole lot of water onto my basement floor. The old furnace was just draining into a hole in the foundation. This furnace is apparently generating more water, and the hole is overflowing.

    I do have a sump pump about 18 feet from the furnace, and it is currently not running, so I do not think under the foundation is saturated. What is going on? Should my HVAC tech have run a hose to the sump pump? If so, I imagine that would have required another pump, because we'd need to go up into the suspended ceiling of my finished basement.

    Thanks in advance.

    DSC05117.jpg
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,801
    Location:
    New England
    Most people use a condensate pump to dump it into a proper drain (often, the washing machine drain is the easiest place). This is a popular brand (I have one of these in my system)...http://www.franklin-electric.com/hvac/condensate-removal.aspx. Depending on the distance and height you need to pmp it, would dictate which pump you'd need. They have an internal float switch, and only run once the reservoir fills up. From my experience, they are quiet and quite reiliable although eventually, they will need to be replaced. As your increase efficiency, you'll condense more moisture out of the flue gasses. It'a also slightly acidic, and not the greatest thing to be dumping into the soil.
  3. caleb_tng

    caleb_tng New Member

    Messages:
    5
    Location:
    PA
    Thanks. The sump pump is the only location available for this. Looks like I will need a condensate pump. I'd install it myself, but I think I want the kind that connects to the furnace and shuts it down in the event of a pump failure. I just had this furnace installed and I don't want to touch it myself.
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,801
    Location:
    New England
    If you're going to run it over to the sump, you wouldn't need a pump as gravity would do it fine. Running pvc pipe for that purpose is easy and cheap. If you really want it to shut the system down, some pumps come with a switch and probably the easiest thing to switch is the 24vac control voltage - that would stop the request for heat, fan, or a/c (the upper drain is for the a/c evaporator). Surprised you didn't see liquid during the summer from it, as you'd normally get more condensate then verses the heating system.
  5. caleb_tng

    caleb_tng New Member

    Messages:
    5
    Location:
    PA
    Thanks. Well, this is a brand new furnace, installed just about 8 weeks ago. The last furnace was draining into this same hole, though, and I never had problems, Summer or Winter.

    The sump pump is in a closet, and there is a finished portion of the basement between the furnace and the sump, so I'd need to go up and across the drop ceiling.
  6. Dana

    Dana In the trades

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    2,780
    Location:
    01609
    The good news is that the extra condensation is a measure of just how much more efficiently the new furnace is running compared to the old- you're extracting far more heat-of-vaporization out of the exhaust that otherwise would have gone out the vent.

    The bad news is that the pink stuff hanging out of the studs isn't doing much for you unless you push/pull/fluff it so that it's fully filling the stud cavities (and not compressed behind plumbing & wiring etc.) and an air-barrier is added to block convective air flow between the room and air in the pinks stuff in the stud cavity. As-installed it's probably performing at less than half the R-value stated on the label, due to the convective air exchange between the room air & the air within the fiber, the convective air movement AROUND the batts where they're pulled out, and the lower thickness where it's been compressed.

    [​IMG]

    The vapor permeance of the air barrier DOES matter, but what it needs to be will vary depending on whether it's a partition wall to a garage, up against a sub-grade foundation, or a fully exposed exerior wall with exterior siding.
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,801
    Location:
    New England
    The outlet of the pump can be flexible tubing, so it's still a pretty easy install if you can fish it over the ceilig. FWIW, both the condensate drain from the evaporator AND the furnace should be trapped (unless the furnace's outlet is trapped inside). I recently cut out a cobbled up trap on mine and used one from this company: http://airtec.rectorseal.com/condensate/eztrap/smarttrap. It's nice because you can get it with caps and a long brush to clean the thing out. You're more likely to need to do that on the a/c evaporator drain than the furnace, but it also makes it nice and easy to see if it's accumulating crud, too.
  8. caleb_tng

    caleb_tng New Member

    Messages:
    5
    Location:
    PA
    Thanks. The installer was back in today to put in a condensate pump, free of charge. I did ask him about the lack of a trap on the furnace drain pipe; he pointed out to me where the trap was located inside the furnace.
  9. caleb_tng

    caleb_tng New Member

    Messages:
    5
    Location:
    PA
    Thanks. That wall actually has the finished basement on the other side. (Unfortunately, since that is where the water was heading.) The guy that did my basement just had some extra insulation and threw that up to help deaden the sound of my old furnace. Also I was pulling at it when I was trying to figure out where all the water was coming from.
  10. Dana

    Dana In the trades

    Messages:
    2,780
    Location:
    01609
    To gain any effectiveness in sound control would require putting up wallboard, and blocking any ceiling joists that pass between the furnace room and adjacent space. But the ducts would also need some insulation to reduce the vibe.
  11. alternety

    alternety Like an engineer

    Messages:
    649
    Location:
    Washington
    Just a suggestion. The condensate from the furnace can be quite acidic. If that becomes a major component of the water in the sump pump it might adversely affect the pump (e.g., eat the non-plastic impellers and casing). Running the discharge through some limestone chips would help. A little assembly can be made out of PVC pipe. You might want to talk to the contractor about this.
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