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hodge12

Furnace condensation and alternate septic system.

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Sure would appreciate advice. Just had a high efficiency gas furnace installed. Furnace now generates about 1 to 2 gallons of condensation water every day or so. Have an alternate organic septic system that won't allow "soft water system" discharge or any high concentration of brine / salt water that will kill the bacteria in the septic holding tank. Furnace company installed drip discharge system leading to outside rain gutter but the condensation "dripping" into the gutter froze last week which caused a backup and shut the furnace down (wife not too happy).

So, plan B would be to drill into house washing machine drain pipe (which leads to septic tank), attach furnace condensation white plastic pipe to washer drain pipe and have all condensation (heat now, AC in summer) drain to alternate septic system. QUESTION - would code allow this in the first place and also would it HARM bacteria in septic holding tank that turns everyting into safe graywater(which ultimately gets pumped to 12 sprinkler heads in back yard?

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. . . So, plan B would be to drill into house washing machine drain pipe (which leads to septic tank), attach furnace condensation white plastic pipe to washer drain pipe and have all condensation (heat now, AC in summer) drain to alternate septic system. QUESTION - would code allow this in the first place and also would it HARM bacteria in septic holding tank that turns everyting into safe graywater(which ultimately gets pumped to 12 sprinkler heads in back yard?

Don't drill into a drain pipe. Just stick the end of the furnace's condensate drain pipe into the washer standpipe. If there isn't room, ask your plumber to add a small wye. Alternatively, direct the condensate into a laundry sink.

I doubt that the condesnate will hurt the bacteria. This condensate is just slighly acidic water.

- Jim Katen, Oregon

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I don't see the connection that you seem to be making between water treated with salt to soften it (which raises it's PH) and gas furnace condensate which is slightly acidic (has a PH of less than 7).

I would look to the manuals on your septic system and gas furnace for specific instructions on handling gas furnace condensation, especially considering that the quantity of condensate would be dwarfed by the volume of other waste water entering the septic system.

Marc

EDIT: Beaten again! 12 WPM and improving.

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There's a couple HVAC installers here that run the furnace condensate through a short 2" PVC pipe filled with limestone chips before being pumped into the septic system.

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On a related note, I've heard that the furnace condensate is just acidic enough to eat away at cast iron drain pipes over time and that the solution is to install a "condensate neutralization kit". That sounds similar to what Bill just described, but I've never seen one. Has anyone heard of this actually damaging the pipes?

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It used to be required around here, but now everyone just dumps it into the floor drain.

I opened up one of the "neutralizer" kits once; it looked like it was filled with limestone tailings.

Personally, I'd do what Jim said. Dump it to the washtub.

Folks eat stuff that's probably more acidic than combustion condensate, and that stuff ends up in the septic. What about the acids in your stomach?

I wouldn't worry about killing the bacteria in a septic system with a bit of slightly acidic water. There's new deposits of bacteria into a septic system on a daily basis.

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Thanks for all the comments! I mentioned that an alternate septic system (pump continually putting oxygen into system to grow bacteria) could not have a water softener unit in the house because that's what the company who made the system advised - they also saw no reason not to introduce furnace condensation as long as the condensation is not high in salt content.

Will discuss this with company that put in furnace. They did want to cut into the black plastic drain pipe and locate the white pvc condensation drip pipe into the washer pipe - but I'm hearing this is not an acceptable way of introducing condensation into the septic?? going directly to the open washer drain next to the washer is not an option apparently.

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