Gas furnace exhaust PVC pipe leaking


  #1  
Old 12-17-18, 10:36 PM
S
Member
Thread Starter
Join Date: Oct 2018
Location: usa
Posts: 36
Received 4 Upvotes on 2 Posts
Gas furnace exhaust PVC pipe leaking

My folks had a Trane gas heater installed 5 or so years ago. After a couple weeks water started to drip from one of the PCV connections coming off the exhaust. They came back to fix it but it started to leak again a year later. There is a small constant drip that Im very concerned about as it could run back down into the unit and cause problems down the road. Even if I were to replace that portion of the PVC there would still be a fair amount of condensation.

I heard a plumber once tell me that he sometimes installs a nipple in the PVC with a hose that runs to the drain so the excess water escapes out the hose and not back into the unit. Has anyone heard of this issue before? I need to fix the leaking pvc but worried about all that excess water. Any help would be greatly appreciated. I will snap some pics tomorrow. Thank you all in advance!
 
  #2  
Old 12-17-18, 11:15 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 65,783
Received 4,122 Upvotes on 3,702 Posts
Normally with a condensing furnace...... the exhaust line is pitched back towards the furnace so that the condensate drains out thru the furnace.

Did they use any glue on the joint ?

Post the model number from the furnace. It can be found on the sidewall inside near the burner.
How-to-insert-pictures
 
  #3  
Old 12-18-18, 07:40 AM
S
Member
Thread Starter
Join Date: Oct 2018
Location: usa
Posts: 36
Received 4 Upvotes on 2 Posts
It's a Trane XR95. They used PVC glue, it leaked, they came back after the call and wrapped the areas with foil tape like a bunch a noobs cause I'm guessing they didn't want to redo the pvc. My parents do not maintain anything, so I end up having to fix all their problems.

As for fixing the pvc. Cutting that entire section out and redoing it seems like the way to go? I've done a few pvc diys so I'm fairly confident I can tackle that part, at least I'd like to think I am. It's all that excess water running back down into the unit I'm really worried out.
 
Attached Images   
  #4  
Old 12-18-18, 07:54 AM
P
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 28,182
Received 2,273 Upvotes on 2,025 Posts
I can't believe they screwed-up simple PVC joints like that. I would cut out the leaking sections and replace with new. It shouldn't be too bad since it looks like there is enough room on the straight pipes to cut and get new couplings in.
 
  #5  
Old 12-19-18, 06:29 AM
D
Member
Join Date: Feb 2015
Location: US
Posts: 8
Upvotes: 0
Received 4 Upvotes on 4 Posts
There is a PVC reducer on a horizontal run of the exhaust. This is a no-no! Reducers should only be used on the vertical runs.
 
  #6  
Old 12-21-18, 04:02 PM
S
Member
Thread Starter
Join Date: Oct 2018
Location: usa
Posts: 36
Received 4 Upvotes on 2 Posts
I cant believe they screwed it up either, then screwed it up again. So if there should not be a reducer in the exhaust gong horizontally. Am I correct in saying the right pipe should be remade the same as the left having the reducer at the top of the 90 bend going vertical?

For future reference and gaining some knowledge. Why is it a no-no having a reducer in the horizontal run of the exhaust?


Thank you all for the help
 
  #7  
Old 12-21-18, 04:16 PM
T
Member
Join Date: Apr 2015
Location: USA
Posts: 771
Received 76 Upvotes on 69 Posts
Condensate running back towards the furnace encounters the reduced diameter (on the horizontal) which functions like a dam until enough water has built up to flow over the top and continue into the furnace. Allows water to sit in the pvc and escape out any poorly made glue joints or worse get all yucky. Probably cause other issues....
 
  #8  
Old 12-28-18, 09:22 AM
S
Member
Thread Starter
Join Date: Oct 2018
Location: usa
Posts: 36
Received 4 Upvotes on 2 Posts
Thank you for the response. Makes sense the way you explained it. Not the same but when I was installing a new vent fan in the bathroom the other day I read so many posts saying never to use a reducer as it drastically reduces the efficiency and sone of the fan.

Now before I attempt to cut that leaky section and replace. Would doing so eliminate the risk of condensate running back down the exhaust into the furnace without having to install a drain hose as my plumber mentioned? I assume I should also just copy the layout of the pipe to the left which was done correctly? Just want to be sure I do it right the first time. Appreciate all the help.
 
Attached Images  
  #9  
Old 12-28-18, 10:22 AM
B
Member
Join Date: Oct 2015
Location: Ct.,USA
Posts: 3,344
Received 315 Upvotes on 278 Posts
When replumbing after cutting out leaky section, use a T instead of a 90 degree elbow to make the transition from horizontal to vertical. At the bottom of the T, add a piece (length to suit) of PVC and end cap. The end cap should be modified to add a barbed fitting for connecting a drain hose. Terminate the drain hose per any local building code. I assume the non leaking PVC pipe is for air in.
 
  #10  
Old 12-29-18, 05:29 AM
D
Member
Join Date: Feb 2015
Location: US
Posts: 8
Upvotes: 0
Received 4 Upvotes on 4 Posts
Copy the intake pipe

make it the same as the intake pipe. You dont need anything else. If you decided to follow the other poster's advice, substitute a wye for the tee and make sure you have some form of trap to keep out exhaust gases. Ninety degree bends should be made with wide sweep fittings.
 
  #11  
Old 12-29-18, 08:52 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 65,783
Received 4,122 Upvotes on 3,702 Posts
I wouldn't add any drain to the exhaust line. Make sure the line is pitched so the condensate drains back into the furnace. It will enter the drain system there.
 
  #12  
Old 12-31-18, 09:06 AM
S
Member
Thread Starter
Join Date: Oct 2018
Location: usa
Posts: 36
Received 4 Upvotes on 2 Posts
You guys are awesome. Thank you all for your help! Going to attempt this in a few weeks. Easy for most but this will be the most challenging pvc repair I've done.
 
  #13  
Old 12-31-18, 09:34 AM
P
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 28,182
Received 2,273 Upvotes on 2,025 Posts
Just take your time. When having to do a complex PVC assembly I first test fit it all together before gluing. If the rotation of fittings will be important mark across the joints with a pencil or marker so when it's time to glue everything together you get everything in the correct rotation.

When doing test fitting it can be difficult to get the pieces fully together. If parts don't seat all the way try to keep track of pieces that didn't seat all the way so you can compensate. Once lubricated by the glue the pieces will easily slide all the way together which can make your assembly shorter than when you dry fit it.
 
  #14  
Old 01-25-19, 06:33 AM
S
Member
Thread Starter
Join Date: Oct 2018
Location: usa
Posts: 36
Received 4 Upvotes on 2 Posts
Well to my surprise, contacting the company did some good. They came out and replaced all the pvc on both sides at no charge. The new owner of the company was very humble and wanted to make it right. Saved me a lot of time and $. Wanted to thank everyone again for taking the time to help. It truly is appreciated.
 
  #15  
Old 01-25-19, 07:31 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 12,682
Received 41 Upvotes on 39 Posts
We have the "before" pictures. How about an "after"?
 
  #16  
Old 01-31-19, 06:47 AM
S
Member
Thread Starter
Join Date: Oct 2018
Location: usa
Posts: 36
Received 4 Upvotes on 2 Posts
The after as requested. He ended up installing a bigger diameter than was previously installed.
 
Attached Images  
  #17  
Old 01-31-19, 02:48 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 12,682
Received 41 Upvotes on 39 Posts
The reducers are now where they should be. As long as the slope is right, you should be in good shape. Good to see the band iron around the pipes for support.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: