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  1. #1
    Join Date
    Jan 2011
    Posts
    14

    Appropriate Condensate Drain

    I have encountered several problems concerning an acceptable solution for draining a high-efficiency furnace & humidifier condensate. If I connect a condensate line directly to the p-trap of a washtub/sink, the sink may back-up and water could enter the furnace. If I drain the condensate into the sump pump pit, the pump will not eject any water since the outside lines are frozen. If the condensation is released into the basement floor drain, pvc pipes would have to run across the basement laundry room floor. If I drain into the wash tub/sink all the way from the furnace, a condensate pump and check valve would be required. What do you consider to be the most appropriate solution, considering the corrosive properties of furnace condensate.

  2. #2
    Join Date
    Jan 2007
    Location
    Coloma MI
    Posts
    214
    If you're concerned about the lines run across the basement floor I'd go with the condensate pump. The condensate is actually not that corrosive however if you have a municipal sewer some communities require a neutrilizer installed on the drain. Mine just goes in to the septic, has been for 20 years with no issues.

    The condensate has a pH level of about 4, which is about the same as a carbonated soft drink. However, furnace condensate is not safe to drink because of trace toxic chemicals it contains.

  3. #3
    Join Date
    Jul 2010
    Location
    georgia
    Posts
    562
    well, for concerns of sink backing up into the furnace, you could use an air gap or a check valve, or if you are using a condensate pump most all of the ones I've seen already have a check valve built into their output line.

    If you are worried about overflow, some kind of alarm would be suggested.

    You may also want to check your local codes as some municipalities dont allow these systems to drain into their sewer.

  4. #4
    Join Date
    Sep 2010
    Location
    Wa.
    Posts
    119
    Where is the furnace?, If it's in the basement you can't run it up through the joice spacing over to a sink or floor drain?

  5. #5
    Join Date
    Jan 2011
    Posts
    92
    a condensate pump seems like your best bet with the limited info. Most HVAC condensate pumps are designed to resist corrosion from acidic furnace drainage. Obtain some 3/8 vinyl hose and run the discharge line along the pvc flue pipe to where it protrudes through the exterior wall. The warm flue pipe will keep the drain line warm without burning it so that the discharging water will not freeze. What I have done in the past is drilled a small hole into the pvc flue just before it penetrates the exterior wall. I then run the vinyl tubing into the flue pipe so that it is protected from freezing on the outside of the house. Most horizontal exterior pvc flue penetrations end with the flue pipe having a 90 degree fitting looking toward the ground. Run the tubing so that it just protrudes from the opening of the end of the elbow.

  6. #6
    Join Date
    Jul 2010
    Location
    georgia
    Posts
    562
    I dont see that being approved in my locality as that method compromises the integrity of the exhaust piping.

    If it can reach freezing point dont discharge the condensate outside.

  7. #7
    Join Date
    Dec 2007
    Posts
    4,690
    Quote Originally Posted by pwg11386 View Post
    a condensate pump seems like your best bet with the limited info. Most HVAC condensate pumps are designed to resist corrosion from acidic furnace drainage. Obtain some 3/8 vinyl hose and run the discharge line along the pvc flue pipe to where it protrudes through the exterior wall. The warm flue pipe will keep the drain line warm without burning it so that the discharging water will not freeze. What I have done in the past is drilled a small hole into the pvc flue just before it penetrates the exterior wall. I then run the vinyl tubing into the flue pipe so that it is protected from freezing on the outside of the house. Most horizontal exterior pvc flue penetrations end with the flue pipe having a 90 degree fitting looking toward the ground.not sue of your experience, but all the units I know of specifically prohibit a 90° down facing elbow on exhaust!!!!!!!!!!!!!!!!!! Run the tubing so that it just protrudes from the opening of the end of the elbow.
    I would not follow this suggestion. sounds like DIY at is finest!!!

    you should keep all condensation inside the conditioned area if there is a chance of freezing.

    you should not penetrate the flue pipe in any way. you do not want there to be any possibility of a leak in that hole and have flue gases leak into the home, Carbon Monoxide.

    use a condensate pump, follow the codes and you will be fine.

    you could always have a professional do it then if something goes wrong there is someone else to take the blame/consequences.
    The Food Stamp Program, administered by the U.S. Department of Agriculture, is proud to be distributing the greatest amount of free meals and stamps EVER.
    Meanwhile, the National Park Service, administered by the U.S. Department of the Interior, asks us to "Please Do Not Feed the Animals". Their stated reason for this policy "... the animals become dependent on handouts and will not learn to take care of themselves."
    from an excerpt by Paul Jacob in Sun City, AZ

  8. #8
    Join Date
    Nov 2010
    Location
    Ontario, Canada
    Posts
    61
    I don't know about the U.S., but in Canada we cant have the condensate line run outside?

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