I have gas clothes dryer in my new home. Behind the dryer you can see metal conduit for exhaust and gas intake and this seems to be where things are hooked up.

Above the dryer, on the wall is a 4" PVC pipe sticking out from the wall. It is covered loosely with a PVC cap and behind it is sealed with some type if paper/tape like material. When the dryer is running, this gets hot and you can see condensation.

My guess was that this was an alternate connection point in case you had a stacking washer/dryer instead of a side by side; however, I wanted to check if this was normal and it it should be sealed this way.

Here are some photos. Would love confirmation that everything is okay or suggestions on what steps I need to take?

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Close up: close up of the PVC port in question

Behind the dryer: photo showing connections behind dryer

  • The pipe that isn't in use is a 4" pipe made of pvc? I can't see that ever being used as a dryer exhaust as it would be a fire hazard. What do the wall caps look like on the outside where the dryer actually exhausts and this 4" pipe terminates. Jan 17, 2020 at 0:05
  • 1
    @FreshCodemonger I think it may not be PVC. Initially assumed because of color. I just knocked it a few times and it had more of a metalic ring and felt harder to knock, maybe its just covered with some white material
    – HelpEric
    Jan 17, 2020 at 0:30
  • It wouldn't suprise me if it was PVC and used for a dryer. It seems MANY people and even contractors use PVC for dryers which is sincerely a bad idea. There are posts about it all over the dang place (including this forum), however, given what you've described and its proximity, it has got to be the vent. The whole entire thing looks like a hack job and I'm not even doing it justice - seeing that I would be looking high and low at the rest of the place. If you didnt get a home inspection, go get one. This is truly unsafe for MANY reasons. DANGEROUS.
    – noybman
    Jan 17, 2020 at 2:44
  • it looks like that was the orig hole, then someone before you dug out the wall down low to fit a new dryer and just capped off the real vent.
    – dandavis
    Jan 17, 2020 at 17:49
  • @noybman can you expand on the danger (asssuming NOT PVC) and if there is anything I can do?
    – HelpEric
    Jan 18, 2020 at 14:47

1 Answer 1

  1. If it looks like dryer vent (location location location & size)
  2. & it smells like dryer vent (gets hot and wet when using the dryer)
  3. & quacks like dryer vent (you hear it, and its hot and wet, and it vibrates)

..... It is a dryer vent.

There are many posts on this forum and threads online where contractors have improperly used PVC for dryer vent. Just because PVC is used on high efficiency furnaces or water heaters does not make it safe for dryer use. It may not be PVC and most likely isn't.

The problem here is that the gasses the dryer produces are supposed to go through the pipe and then OUTSIDE. It is not safe for there to be holes or exit points for the exhaust INSIDE. While no one can say what levels are produced by your dryer, what can say is it will fluctuate. If the duct gets clogged, WHICH IT WILL! THEY ALL DO! (and this is why it is imperative you have it cleaned every 6-12 months or so on average; your mileage will vary), then the burn quality of the gas will be reduced, in addition, the clogged vent will force air wherever it can... Inside your home?

Next, the flexible ductwork - its best to have a rigid metal duct system in place but people use the flexible because its fast and simple. For short runs, its generally fine. If your run is long, it is not. If this system has a "T" unit in its line (it looks like it does) it really shouldn't, and this will "catch" lint as it blows past it. An odd plus here, is this gives you easy access to clean it out. (but its still a point gas can escape).

The one picture shows the dryer gas inlet as a straight 180 out of the dryer and they put the flexible gas line right to it, it (the dryer) is now pushed against the wall (by everyone that touches it), and the line is in danger of being kinked. This needs a 90 degree elbow to prevent this.

The dryer appears to be installed right where a beam in the wall is, so they went to the side quite a ways so there is now two bends, and the flexible duct may be getting compressed/squished in its compromised tight quarters.

They hacked the drywall and left it that way. Thus compromising the wall void. Completely avoidable. You can buy metal or plastic boxes to make this pretty and accessible:

Example website with pictures, (not promoting this company over any other)

This install was done poorly, sloppy, and wrong. You stated this is a new build house, I would have a home inspector, or family friend or relative take a walk through the home and make sure everything else is "right". They wont see everything, but they may find other issues you can get addressed under warranty perhaps.

Good luck.

  • To confirm, there is a vent that goes up and out the roof (this is on the second floor). So they issue is the "second" vent increases the likelihood of gas leaking and that the projection will catch lint. The kinks at the bottom also increase the likelihood of lint catching and decrease efficency. If the venting out the roof is done correctly, it's not like the second vent will just shoot off one day, right?
    – HelpEric
    Jan 19, 2020 at 20:53
  • also, to ensure I understand - the gas line issue is on the right side - it goes into the wall then curls around up and to the connection on the left. That initial kink out the back is where a 90 degree connector should go, correct?
    – HelpEric
    Jan 19, 2020 at 20:55
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    Roof venting is ok in certain areas. It is generally not preferred because of numerous reasons. The length of the run matters, and every bend adds a 3-5' decrease in the total allowable run the dryer can support. Look at the owners/installation manual for the model dryer you have, subtract the bends per its formula, is your run even legal? Sure, the tape can dry out or burn, cant tell you what the cap will do today or in 50 years. I've described the dangerous gas line connection as it is seen in the picture.
    – noybman
    Jan 20, 2020 at 0:48

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