Drain pipe from furnace issue

Specific Inspection Topics Inspecting HVAC Systems
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so its 3 degrees here and i went in my attic to check to see if my old windows were holding up ok and notice a puddle of water under my condensate pump hooked to my furnace. the line was frozen and no shut off wire was installed to stop it from pumping so water was leaking out of the seems basically.

last year i had a furnace installed in the basement and attic. my other furnaces were the old ones from 1980, so the new furnaces had to be hooked up a bit different. the old one never had a condensate pump.

they hooked a plastic flexible line upwards onto another pipe and zip tied it across the ceiling and then shoved that tube into previous old pvc pipe

the attic gets to cold for this and freezes the line then the pump overflows. on top of that the old pvc pipe they spliced into which is around 30 yrs old doesnt angle very much at all

the company refused to come out and look at their installation or anything at all. didnteven tell me what to do, to turn the furnace off etc.

so i had a new furnace guy here today. he basically said the way they ran the wire its prob just going to continually freeze even if we wrap the flexible plastic, the pvc leading outside is prob still going to freeze. i also have blown in insulation a few feet deep on the entire attic floor making this worse to get to anything at all

the only solution we came up with is using pvc pipe on the pump, trying to slope it as much as possible by moving insulation out of the way, wrap it in heat tape, and then put insulation over that. and then heres the big thing, running that pipe into the stink pipe by the wall.

will this be ok? its relaly the only solution that makes sense to keep it from freezing, and the closest place to drain it because the old pvc pipe goes under the corner of the house into the insulation and outside down the entire house in some sort of metal tube and its a victorian so it also goes through this custom ridge that sticks out ofthe house. in short itll be a nightmare to even get to that spot. the initial installers never wrapped anything and never said hey this might freeze on you etc. i dont have a problem with the ac water draining in the summer but were prob going to just run that pipe into the same stink pipe as well so if any of that 30 yr old pvc pipe cracks it wont rott my wall out for months before i notice it.

i dont even know if im on the right webpage asking this, sorry if im not, i saw a different thread where someone tried to do something similar. im just really lost right now. i have my pump temp draining into a bucket until the guy can comeback in a few days and re route this stuff

edit, updated with 2 pics and a video that i took before i had a furnace guy out. i drew a yellow line to follow drainage line to make it easier to know what your looking at.

edit, getting a 422 error from pics, had to remove them

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Hi Mike,

Do you have pictures that you can share?

Many find looking at the issue helpful. Use the up ^ icon 5th to the left of the gear icon to upload pictures.

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307.2.1.1 Condensate discharge.Condensate drains shall not directly connect to any plumbing drain, waste or vent pipe. Condensate drains shall not discharge into a plumbing fixture other than a floor sink, floor drain, trench drain, mop sink, hub drain, standpipe, utility sink or laundry sink. Condensate drain connections to a lavatory wye branch tailpiece or to a bathtub overflow pipe shall not be considered as discharging to a plumbing fixture. Except where discharging to grade outdoors, the point of discharge of condensate drains shall be located within the same occupancy, tenant space or dwelling unit as the source of the condensate.

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Depending on where it is freezing (In the attic space or at the exterior?) you might want to terminate the drain line to an interior drain instead of to the exterior. Like the picture shown or just run it to the stand pipe for the washing machine.

Another reason I don’t like HVAC systems in the attic space.

Condensate drain
Condensate drain1570×1114 339 KB

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I would not use PVC pipe since it is not rated for heat. I would look at CPVC, it could better handle the heat tape you are thinking about wrapping around the pipe.
This might give you some ideas…https://heatline.com/ideas/prevent-high-efficiency-furnace-condensate-lines-from-freezing/

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I have a thing about heat tapes, possibly fire hazard.

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It sounds to me like a furnace that produces condensation has been installed in an attic space that encounters freezing temperatures.

The only way to properly correct this issue is to install a drain line that is graded at no less than 1/8 inch per foot and does not use a pump. Pumps have standing water in them. Standing water freezes in attics that encounter freezing conditions.

The installation was doomed to fail since day one. I suspect a category one furnace was removed and a high-efficiency furnace was installed in its place.

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This is a great way to destroy a high efficiency furnace if it ever locks out or you lose power.

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hello it kept giving me a error for pic uploads, so i edited my post with a video i had made when i first noticed the issue before i had someone come out. it should should a prettyg ood idea how its ran mostly in the video. thanks!

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hi, do you know the reasoning behind this code by any chance? were going to install a trap in the pipe as a safety measure. my sump pump in my basement goes into a similar pipe i would think that would be worse.

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hi i uploaded a video you can see a giant black pipe by the wall, thats what i was calling the stink pipe vent pipe. im not sure if thats the same as the pipe in your picture. its a big victorian house and the washer and first bathroom is on the first floor, second bathroom is on the second floor and this furnace is in the attic ( i have a furnace in the basement which is ok and the pipe just runs into some drain hole). but i dont think i can reach a sink or bathtub unless we drill through the ceiling?, the shower tailpiece and trap im not sure where thats located, i have a clawtub with a shower extension on it.

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hi thank you ill make a note of that to buy cpvc, i was also wondering that as well, from what im browsing on home depot it doesnt seem to cost that much more. is that correct?

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i have the same concern about heat tape, in general im nervous about even candles. i just dont really have any other idea

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your correct a old furnace from the 1980s was removed and high efficiency one put in and some conversions. looking at what i see now i also see it was doomed from install, the hvac people should of known this . they should of also at least came back out today and investigated their install to see they were wrong. but moving forward, surprisingly the water inside the pump wasnt frozen just the line. from what they told me last year during instal was the pump was put on so things wouldnt freeze. which turned out to not work.

forgive me for sounding stupid when i ask this but when you say "install a drain line that is graded at no less than 1/8 inch per foot " what exactly does that mean, are you talking about the flexible plastic tube drain line and it has different types of grades?. also my big issue here is whereto run the drain line. trying to run it back outside doesnt seem like a option.

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hi jeff thanks for the reply, were you saying martins solution sounded like it would destroy the furnace (by removing the pump?) or were you saying my install in general sounded like it would destroy the furnace. im thinking leaving the pump on would be better and hooking up the safety shutoff so if something happens in the future the furnace will shut off and ill know there is a issue in the attic since im rarely up there.

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If the furnace is located in an unconditioned space and the power goes out, water/condensate can freeze in the furnace components. The same thing could happen in a conditioned space as well if the area drops below freezing for a long period of time.

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The plastic tubing that they have installed at the ceiling in your attic does not need to be there. The drain it ties into, which is PVC, can be ran towards your furnace and the furnace condensate can drain into that pipe. That is the pipe that needs to grade at 1/8 inch per foot towards a downward direction.

It may be necessary to raise the furnace to allow proper drainage into the condensate drain without the use of a pump.

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I think the main purpose is what you may have alluded to, that sewer gases could possibly back up into the drain line and into the attic space.

Could you tee off the vent pipe with a stand pipe and a trap for the condensate drain to discharge into? I’ve never seen that, but Martin @mwilles is sort of the resident plumber, maybe he could answer that. But there is still the possibility of water freezing in the trap.

I can see in your video that the furnace sits below the floor height in your attic. Unless the furnace is raised, as of now your only option is a condensate pump to an “approved“ location. I think what may be happening is condensate is freezing in the “bellies” of the loosely supported flexible drain line, preventing any further water from getting through. That is something else that would have to be corrected.

What I can’t see in your video is a drain pan under your furnace. This could be a problem if a leak develops which could damage the ceiling below. The drain pan would be connected to a drain line in a similar fashion that Martin described. This could also be a problem in the future.

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The humming noise is the pump trying to do it’s job, but since the drain line is frozen the water has nowhere to go so it keeps running.

Here is a possible solution to consider with insulating your attic space with spray foam. Hard to tell but the attic does not appear to be very large. This maybe the best money spent as it would also reduce utility expenses.

I would also be looking for another HVAC company for future service and repairs.

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Sorry, I have no clue on the cost differences

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