High Efficiency HVAC Condensation Line in Abandoned Chimney

David Triplo · 2020-07-29T17:18:07-07:00

After some searching, I determined where my water issue was coming from in my ground unit in my 1890s, gut rehabbed 3 flat. In my 95% high efficiency HVAC system the PVC pipe connected to a copper pipe in my abandoned chimney on the 2nd floor was corroded where they met which leaked outside of the chimney causing damage to my carpet in the ground unit beyond the drywall. The chimney is not exposed in any unit and has been drywalled off. I had a plumber repair the pipe and he said the pipe should not be in the chimney at all. I haven't been able to determine if the pipe leaves the chimney and exits properly to a drain or just drips to the bottom and dissipates. I used an endoscope and know it goes down at least 15 ft to the 1st floor and seems like it goes lower. Is it ok if the pipe doesn't leave the chimney at all and eventually dries out? Should this condensation line be moved? I've had a large range of opinions between chimney people, a plumber , and a home inspector. There's an odd drop ceiling in the ground unit and think a pipe could run along the area, but don't want to keep cutting holes in the drywall to see if it's not necessary. There's not a convenient location from the HVAC to move the line and the plumber quoted me at 3K to move the pipe and knock down a lot of walls to do it. Separately, since the chimney is abandoned, it was recommended I remove the chimney below the roof line. Since this is true other than this pipe, would it be ok to do this if the water really is just dissipating at the bottom of the chimney? I'd appreciate any advice. I just wish I had consistency among the contractors to know if it's ok if this pipe is running down the chimney or not.

Pat L.

Rental Property Investor · Upstate, NY · Member since 2012 · 3k+ posts · 3k+ votes

6y

We had a HVAC condensate line running out through the siding & into a French drain outside. The plastic line broke & the condensate ran down the 15 yr old cement poured basement wall & it literally spalled the cement 1/2inch deep. Apparently condensate from a Hi Efficiency Fce can have a pH ranging 3.5-6.5, effectively 10x more acidic than tap water. So it's probably NOT a good idea to have it running down into a brick chimney, hoping it just dries up somewhere before it hits the old ash dump.

1 Reply

Russell W.

Rental Property Investor · IL · Member since 2015 · 165 posts · 107 votes

6y

I tend to agree that allowing it to drip inside the chimney is a bad idea. It will likely affect the mortar joints over time. Without knowing exactly where the HVAC unit is located in the apartment, there could be a couple options. Is there a kitchen or bathroom relatively close? You could use vinyl tubing to allow the condensate to drain into the p-trap, similar to a dishwasher connection (obviously this would require some drywall work unless the HVAC closet shares a wall with kitchen/bath). The other option, though perhaps not as visually appealing, would be to run PVC condensate line through the exterior wall and down to the ground to drip onto soil/sidewalk/whatever happens to be there. You could run it tight against the outside face of the chimney to keep it neat looking.

0 Reply

Don Meinke

Investor · Northeast, NE · Member since 2015 · 258 posts · 83 votes

6y

No to letting it drip inside and having it evaporate.

I am not clear here, there are 3 hvac systems? Where are the other two drained? And was this installed previous to your owning this?

Don’t you still have access to the ash dump door at the bottom in the basement? Old chimney pipe holes?

Chimneys usually have space alongside them, maybe you can fishtape in a drain pipe there.

You have to make this better somehow

0 Reply

David Triplo

OP

Chicago, IL · Member since 2016 · 18 posts · 2 votes

6y

Sadly there’s no close bathroom or kitchen, which is why the plumber quoted me at 3k to move the pipe and knock down a bunch of walls. The chimney is in the center of the building. This would run against the chimney to the bottom unit and out the kitchen drain. The HVAC unit is next to the exterior wall so I would be fine running that outside if it’s legal.

There’s 4 total HVAC. One per floor. The bottom 2 are in the basement next to the sump pump. The 3rd floor is the problem HVAC. The top floor is above a bed and runs out another source. This one was installed 6 years ago and I just purchased it a year ago. The chimney is drywalled off from each unit so you wouldn’t even know it existed in any unit so not sure if I could gain access to the ash pump door or if it’s even there. I’ve only opened up 2 portions of the basement drywall and doesn’t seem like there is one.

0 Reply

Matt R.

Blue Springs, MO · Member since 2015 · 481 posts · 313 votes

6y

If you can easily disconnect the drain pipe at the furnace, and you have access to an air compressor: disconnect the drain pipe, have an accomplice plug a blow gun into the air compressor, and then blow air into the pipe - the same direction the water flows now. Then snoop around downstairs, inside and outside, to see if you can hear the hissing sound where the air is coming out. This might help you figure out where the other end of the pipe is. NOTE: If the drain pipe does just dump into the old ash pit, you might have ashes from 1895 blowing around when you do this.

I am not a plumber, but I'm not sure you can run PVC on an exterior. Also, since a 95% gas furnace will make water in the winter, consider what happens to an exterior condensate drain - if the outside pipe freezes, it could back up into the furnace or otherwise spill into the house where you don't want it.

You can get an electric pump that can be plumbed into the condensate drain line. It needs 120 V, and has its own float switch to turn itself on and off. This might be something to look into if moving the water up would help. Like, if the furnace is in a closet on the outside wall, put the pump on the floor next to the furnace, then run a pipe up to or through the ceiling, horizontally through the ceiling or attic, and then back down into a bathroom or kitchen, where you can connect to an existing drain. A heating and cooling contractor should be familiar with these; plumbers will probably be as well.

1 Reply

David Triplo

OP

Chicago, IL · Member since 2016 · 18 posts · 2 votes

6y

I finally found out where the condensation line was running out of. I was fed up with the issue and just made a much larger hole in the drywall in the bottom unit (where I live) and there were 2 openings in the chimney. There was a ton of insulation inside and outside of it. The corroded pipe was dripping down the chimney, hitting the insulation and then dripping outside of it resulting in my carpet getting wet from one hole. The other hole also has some more hidden water damage where the pipe connects to the plastic pipe. It's good to finally know where it's located, but now it seems like I need to replace the entire pipe going down the 3 story chimney. There's barely any room between the drywall and chimney so if I decide to move the line outside the chimney, it would be a much bigger deal with the drywall project and disrupting my middle tenant.

If anyone in Chicago has a recommended handyman, HVAC guy or plumber, I would appreciate it. I have my plumber, which wanted to move it outside the chimney, but I'm trying to avoid the bigger project and bill if it's not necessary. I have Roto-Rooter coming Monday for a free quote and a friend's contractor next week, but my friend's contractor probably can't resolve the problem relatively soon.

1 Reply

High Efficiency HVAC Condensation Line in Abandoned Chimney

High Efficiency HVAC Condensation Line in Abandoned Chimney

Most Popular Reply

6 Replies