Condensate pump output

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by richbl, Dec 12, 2009.

  1. richbl

    richbl New Member

    Messages:
    9
    Hello all,

    After spending some time reading about my options, I don't seem to have any definitive solution. So, I'd like to pose this question here:

    Can I run a 3/8 flexible copper condensate line (from a high-efficiency furnace condensate pump... a Diversitech CP-22) into an ABS waste line?

    My current configuration has the condensate line running outside, but in colder temperatures (here in WA state, it seems to have gotten progressively colder), the line exiting the house occasionally freezes up.

    As the condensate pump is between the furnace and the waste line, there's no chance of a back up of sewage or gases, which seems to be the most highly-debated issue against this approach.

    I've parsed my copy of the 2006 IRC, but cannot find anything definitive there either.

    Your opinions please.

    thanks,

    rich
  2. Ian Gills

    Ian Gills Senior Robin Hood Guy

    Messages:
    2,777
    Location:
    USA
    I wouldn't do it for a whole host of reasons. It would not be vented and you are putting a lot of faith in the pump's check valve.

    Discharge it to a bar sink or a utility sink with a nice big air gap if it's freezing up.

    Or get a nice high loop on the existing line so that it siphons clean when the pump pumps.

    That will mean there is less water in the pipe to freeze up.
    Last edited: Dec 12, 2009
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,230
    Location:
    Cave Creek, Arizona
    condensate

    There is no need for a vent, and as long as it is not connected directly to the sewer system it cannot back siphon either. It is NOT a code issue.
  4. Ian Gills

    Ian Gills Senior Robin Hood Guy

    Messages:
    2,777
    Location:
    USA
    So the ABS waste line is connected to what?
  5. richbl

    richbl New Member

    Messages:
    9
    Thanks for the quick responses.

    Some clarifications might be in order.

    Here's the current configuration for my furnace system:

    furnace ---> 3/4 PVC ---> p-trap ---> 3/4 PVC ---> condensate pump ---> 3/8 flexible copper ---> outside

    What I'd like to do is re-reroute the condensate out to my ABS waste lines that go to septic.

    As my furnace is below grade (basement) and below waste lines, the condensate pump is obviously necessary.

    If the copper condensate line goes to ABS waste (my original question), I was hoping to do this with an ABS wye capped with something like a clean-out or similar reducer. Since the waste line itself is vented, I don't see the problem unless that branch of the waste line were to back up. Were this to occur, and the condensate pump check-valve failed, the worst case would be the condensate pump flooding with waste water.

    The easy solution would be a run to the nearest utility sink (as suggested), but there are no open waste lines (sinks) in the basement.

    What else am I missing here?

    thanks again,

    rich
  6. Doherty Plumbing

    Doherty Plumbing Journeyman & Gas Fitter

    Messages:
    810
    Location:
    Penticton, BC
    Run the line so it's ABOVE the counter and dumps into the sink itself, not the drain.
  7. richbl

    richbl New Member

    Messages:
    9
    Since the furnace is in the basement, and there is neither a sink nor drain below grade, this is not an option (it would be too easy otherwise!).

    All waste lines are in the open (unfinished) ceiling of the basement.

    thanks,

    rich
  8. Doherty Plumbing

    Doherty Plumbing Journeyman & Gas Fitter

    Messages:
    810
    Location:
    Penticton, BC
    Oh I'm sorry I completely read your post wrong!!! I thought you were saying there was no exposed sink drainage in the basement. But then I reread it and it makes sense now :D

    I don't like tying in condensate pumps directly into a sanitary system but I have done it before I'm not gonna lie. If you're stuck with this option Make SURE you run some piping horizontal but graded towards the drain so you can install a swing check in this location.
  9. richbl

    richbl New Member

    Messages:
    9
    Good idea to go with a check valve. But, I have a couple of questions:

    --Is there such a thing as a check valve for ABS (2" or less)?
    --With such a small amount of condensate that flows, would a check valve impede water flow into the waste line?

    I imagine a lot of standing condensate ahead of the valve, which is acidic (mildly). Not a good thing, I'd think. And going from 3/8" to a 2" ABS run, I lose any pressure that I might've had.

    Maybe I'm just overthinking the issue.

    thanks,

    rich
  10. richbl

    richbl New Member

    Messages:
    9
    Could you please clarify your statement?

    I'm not sure I understand your comment about what is or is not a code issue.

    thanks much,

    rich
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