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Acceptable for Mod-Con Boiler Condensate line to run to Sump Pump?

Sorta Member Posts: 46

Hi all.

Currently, my condensate line drain goes in to a hole drilled in the concrete floor of the garage (mod-con boiler is in garage). But I'd like to change this. There is a sump-pump in the corner of the garage. Would it be acceptable for me to run a long pipe from the condensate disharge to the sump pump?

The end of the boiler drain pipe is only a few inches from the floor. And it will require a steeper angle for gravity to take the condensate the distance to the sump pump. Would it be okay to cut the boiler condensate drain pipe shorter? This would make the end of the condensate pipe high enough that when I attach an elbow/new pipe…it would provide a good angle so the condensate wouldl flow down to the sump pump.

Thanks for your help & suggestions.


  • Sorta
    Sorta Member Posts: 46

    I'm reading more about condensate lines. I'm in New York. I found the "2020 Plumbing Code of New York State" publication, which seems to be the most recent publication. Regarding condensate, it says:

    "SECTION 314
    [M] 314.1 Fuel-burning appliances. Liquid combustion by-
    products of condensing appliances shall be collected and dis-
    charged to an approved plumbing fixture or disposal area in
    accordance with the manufacturer’s instructions."

    They italicized "approved". So this means that the boiler manufacturer has to say the plumbing fixture (sump pump) is approved for this particular boiler? I don't think it means that NY state has to approve the plumbing fixture, right?

  • Sorta
    Sorta Member Posts: 46

    Oh, and just had an idea about my question about cutting the condensate discharge boiler pipe.

    Where the condenstae pipe comes out of the back of the boiler, can I simply turn the pipe to an angle…instead of it hanging vertically?

  • hot_rod
    hot_rod Member Posts: 20,827

    it is a good idea to run the condensate through a neutralized. That could be down where it discharges into the sump pit.. If not that highly acidic condensate will attack ant metals. Is the sump pump plastic, The pit?

    Where does the sump pump discharge to?

    There is sometimes a trap inside the boiler to prevent exhaust fumes from coming out the condensate line. As long as that seal, water level is maintained you may be able to tilt the discharge tube. A pic would help see what you have.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Mad Dog_2
    Mad Dog_2 Member Posts: 6,475

    Yes. Pics would help. You're making me a little nervous when you say "discharge" pipe. Let's make sure you're not talking about the pressure relief discharge piping. Please post a picture of all the piping under the unit. Mad

  • mrhemi
    mrhemi Member Posts: 28

    All of the above comments are pertinent. I will add my personal application to consider. I ran all of the condensate drains, boiler, HVAC, humidifier, HRV etc. To one sump pump. Reason is by filling the sump pump basin periodically it keeps the pump and controls exercised to help insure it does come on when needed. In this application, I have an "A" & "B" pump cascaded. "A" pump is primary and carries normal load. Without all of the condesate drains entering "B" pump, it could actually goes for years without activating then quite probably fail to start when needed. These discharge into a separate (from sanitary) storm sewer. Been this way for 8 years with no ill effects from corrosion. Sump pumps are great, until they don't work when you need them most.

    Licensed Steamfitter.
    Licensed Instrumentation & Control Technician.
  • Sorta
    Sorta Member Posts: 46

    Thank you for your helpful replies Hot Rod, Mad Dog and MrHemi.

    Definitely not the pressure discharge pipe, sorry about the confusion. It is the condensate pipe from the back of the boiler. And a neutralizer is a great idea. The thing is, the sump pump basis is indeed metal. So maybe it isn't really such a good idea to even try it. I'll find another place to run the condensate piping.