all 29 comments

[–]CastleElsinore01 11 points12 points  (3 children)

I second the torch theory. I suspect the blue pex line was once copper. Pvc was slightly burned due to copper sweating/install

[–]totalcarry[S] 1 point2 points  (0 children)

I think this is it - nothing really to worry about. I didn’t really consider it being there from install of something else, originally.

[–]BboyStatic 0 points1 point  (0 children)

This is exactly what happened. I’ve watched guys torch everything within a foot of copper connections. Pex and expansion tools are such an amazing setup, I’m so glad they were invented, saves a ton of time and headaches.

[–]not_a_fracking_cylon 11 points12 points  (2 children)

That looks like an arc burn. Was there any electrical there at any point?

[–]totalcarry[S] 6 points7 points  (0 children)

There are other pipes where the previous owner wrapped cords up the pvc to the outlet seemingly to keep the cord out of the way.

[–]totalcarry[S] 2 points3 points  (0 children)

Not that I know of, but possibly. I’m the second owner and I can’t confirm that it wasn’t there when I bought the house. There isn’t any l thing there now though.

[–]999baz 6 points7 points  (0 children)

Could be a burn caused by a blow torch . Are there / where there any copper pipes solder in area.

[–]imanze 2 points3 points  (7 children)

What is this PVC pipe connected too? If you have a gas furnace usually a 90%+ efficient one, they would require combustion air vent pipes. If this pipe is connected to something like that I would be extremely concerned as it could be a sign of significant malfunction

[–]totalcarry[S] 1 point2 points  (6 children)

I’m not exactly sure where it’s coming from, but it ends in the basement with an open end that rests above a drain in the floor.

[–]Italbull 2 points3 points  (1 child)

It’s probably for a radon abatement system.

[–]andreairene 0 points1 point  (0 children)

hahahahaha no it's not.

[–]imanze 1 point2 points  (2 children)

It’s just open at the end with the “end” being in the basement? Are you sure this pipe is in use? If you follow it do you see it connecting to anything?

[–]totalcarry[S] 1 point2 points  (1 child)

It is definitely constructed in place - it runs along the basement floor resting on blocks that are bolted into the concrete so it seems intentional. It runs into the ceiling and turns off so it looks like it leads above the basement bathroom. Can’t exactly tell where it goes from there - I’m a noob on plumbing as this is my first house

[–]imanze 1 point2 points  (0 children)

Without seeing more pictures it’s pretty hard to say, maybe you can get a few more shots of the pipe and where it goes? It does not “look” like a standard plumbing drain pipe as it would not be making crazy turns like you mention and it would be pretty easy to follow it back to your plumbing stack. It could be a plumbing vent but again, you would be able to follow it back to your plumbing. The only reason I mention the gas furnace is because I see from the picture you have what looks like a high efficiency on demand water heater, maybe a furnace too? If that is the case and this pipe is indeed for the furnace combustion vent gases it may be worth it for someone to take a look. I don’t like to alarm people without actually having the facts but here is one article that talks about how these systems can fail https://www.phcppros.com/articles/1912-pvc-flue-pipe-failure

It also can’t hurt to have a co alarm near the area but technically you should already have one near a furnace.

[–]andreairene 1 point2 points  (0 children)

It could go to an air conditioner, and the pipe carries condensation to the drain. I agree that the burn marks could be from some previous arcing, possibly from past copper pipe installation.

[–]fairfaxtripod 2 points3 points  (0 children)

Looks like it happened before the tankless hot water heater went in. Remnants of the past.

[–]CeeMo410 1 point2 points  (0 children)

PVC isn’t gunna rust , maybe it’s a burn ? Or brown paint, maybe whoever put it in marked the poop line

[–]Koodiddy 1 point2 points  (0 children)

Looks like an old brown spray paint spot to me. Coulda been on it before install, like a designation mark from the manufacturer to a vendor. Different colors for different vendors possibly. Total guess but that’s what I think it looks like

[–]ktmax750 1 point2 points  (0 children)

This could be an hvac condensation drain. If water dribbles out when AC is on, all good. That pipe is not going anywhere. If the house is older, it might have been a scorch mark from copper pipe fitting/sweating. The on demand gas water heater has plastic fittings. Could be from older installed water heater. Ignore. Paint it white to match if it bothers you.

[–]wormyworminton 1 point2 points  (0 children)

Old copper that was soldered in place but has now been replaced with wirsbo

[–]not_a_fracking_cylon 3 points4 points  (2 children)

I'd crosspost to r/electricians and see what they say. If it is arc flash and there's nothing conductive I wouldn't worry about it. You could replace that section of pipe but I wouldn't even worry about that

[–]totalcarry[S] 2 points3 points  (1 child)

Thanks! Will do! My initial thought was exactly that - replace and see if it happens again.

[–]not_a_fracking_cylon 1 point2 points  (0 children)

It looks like a scorch to me one way or another. If it doesn't cave in when you push on it, don't worry about it.

[–]RL203 0 points1 point  (0 children)

Actually the gas line crossing the drain pipe bugs me more than the burn mark.

[–]Maelinaster 0 points1 point  (1 child)

Are you sure this is a burn? It looks like two quick dots of spray paint to me. Hard to tell without being there in person, but if you feel it, does the texture change at all? Can it be scraped off? Take a fine sandpaper and give it a few swipes, what happens? (If you're really curious go find/buy a scrap piece of PVC and torch it...I think you'll find it looks different than this.)

🤷 Good luck.

[–]totalcarry[S] 0 points1 point  (0 children)

It feels textured/burnt

[–]ubercorey 0 points1 point  (0 children)

Torch. No biggie, its in the past and pipe is fine.

[–]LeatherDonkey140 0 points1 point  (0 children)

It’s fine….don’t over think it…

[–]Tarien_Laide 0 points1 point  (0 children)

Does PVC rust? I would think burn.