Copper in the way


  #1  
Old 09-17-18, 05:39 AM
E
Member
Thread Starter
Join Date: Dec 2011
Location: Canada
Posts: 262
Received 2 Upvotes on 2 Posts
Copper in the way

Needed to lift up subfloor for unrelated project and found this situation (see photo). The copper for upstairs plumbing runs from those pipes shown (note that cold supply is not shown. They also squeezed in a 5" hvac supply duct, which I have removed, but you can see the 90* boot where it was attached.

While I have the floor up I want to fix this situation as the copper that is there is obviously too rigid to allow me to finagle the supply duct back in (the original had some dents and other evidence that they really squeezed it in). I also need to put in some blocking to brace the old and new subfloor edges. I want to lower the copper to create more room for the duct which I will also need to lower.

I went and bought some flexible ducting as a last resort but I was thinking about using those push-connect fittings (made by sharkbite, et al) to make the plumbing a bit more flexible. Even with the flexible duct, it is a tight fit and I am afraid of kinking the duct, etc.

Thoughts?

Name:  p1.jpg
Views: 89
Size:  16.3 KB
 

Last edited by PJmax; 01-14-20 at 05:47 PM. Reason: resized picture
  #2  
Old 09-17-18, 06:06 AM
Marq1's Avatar
Member
Join Date: Sep 2016
Location: USA MI
Posts: 9,745
Received 1,210 Upvotes on 1,098 Posts
First off, plumbing really is not supposed to be "flexable", second, and I know others will disagree. I would not put a slip joint (sharkbite) type fitting into an enclosed space,

They work but they are not a permanent fitting like copper fittings!

Third, your plumbing is pretty low in that bay, you would need to go to the bays on either side to jog the pipe down to gain just a min of space.

Personally if the duct was there and the seams taped a small dent would not be a problem.
 
  #3  
Old 09-17-18, 07:07 AM
Z
Member
Join Date: Jan 2008
Location: Southeastern Pennsylvania
Posts: 3,375
Received 121 Upvotes on 112 Posts
Not a pro but I agree with Marq1, Sharkbites won’t make it flexible. I think you might be able to drop that horizontal pipe a little by using 4 Sharkbite 90’s and then locating the new horizontal piece lower and more forward, that is, more towards the front of the picture. I think that would work, not totally sure, can’t tell from picture but it looks like it would work.

I guess that would be a little clumsy though and I think a lot of people are reluctant to use Sharkbites in enclosed spaces. But I know some do. Not sure but I think some plumbers are OK with that.

I don’t think I would do it. I would solder 4 90’s if I really really had to drop that horizontal pipe a little bit for some reason.
 
Attached Images  
  #4  
Old 09-17-18, 07:46 AM
2
Member
Join Date: Jan 2014
Location: USA near Boston, MA
Posts: 2,251
Received 388 Upvotes on 337 Posts
Not sure I understand the problem. The duct fit before so it should fit again. A small dent won't cause a big problem. A piece rubber or insulation between the duct and the pipe will isolate one from the other. You could also consider a transition at the 90 to a rectangular duct crossing the pipe. The size of the rectangular duct should have the same square inch area as the round duct.

Leaking air from a poorly fitted duct is a lot less troublesome than a water leak!
 
  #5  
Old 09-17-18, 01:35 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 64,816
Received 3,922 Upvotes on 3,518 Posts
A small dent won't cause a big problem.
I agree 100%. Just squeeze the duct slightly making it oval shaped over the pipe.

Sharkbite fittings are approved for buried use but it is not something I would do or recommend doing.
 
  #6  
Old 09-17-18, 07:00 PM
czizzi's Avatar
Member
Join Date: Jul 2007
Location: USA
Posts: 6,541
Received 15 Upvotes on 13 Posts
Your HVAC supply line need not be rigid, it can be semi-rigid to allow you to squeeze it into the space provided. I don't see anything else wrong if you can fit the duct work in. I also will not bury a shark bite in a wall or floor cavity that is not accessible. I have seen them fail in the past.
 
  #7  
Old 09-18-18, 03:31 AM
E
Member
Thread Starter
Join Date: Dec 2011
Location: Canada
Posts: 262
Received 2 Upvotes on 2 Posts
It's easier to fit when there isn't any drywall up! Don't know who goes first, plumbers or hvac, but it definitely looks like they were put into a spot with the way the two systems were designed. A related question: are you supposed to have galvanized sheet metal duct sitting on top of copper? Nothing seems to have happened over the 30+ years that it's been that way but I seem to recall it shouldn't be done. Think I will go with a flexible duct. And, yes John, air leaks over water leaks every time!! Thanks guys!
 
  #8  
Old 09-18-18, 07:46 AM
2
Member
Join Date: Jan 2014
Location: USA near Boston, MA
Posts: 2,251
Received 388 Upvotes on 337 Posts
Flexible duct may reduce the air flow a little bit but probably not enough to notice. Solid duct could be installed in sections. Cut two sections that can be mounted onto the existing at both ends and just meet at the middle. Then seal the middle joint with a strip of duct around it and tape. Like using a pipe clamp on no-hub pipe.
 
  #9  
Old 09-19-18, 05:59 AM
E
Member
Thread Starter
Join Date: Dec 2011
Location: Canada
Posts: 262
Received 2 Upvotes on 2 Posts
That is why I love posting questions on this site. Never in a million years would I have thought to do that John. Thanks.
 
  #10  
Old 09-19-18, 04:34 PM
L
Member
Join Date: Nov 2015
Posts: 1,572
Received 201 Upvotes on 172 Posts
A piece rubber or insulation between the duct and the pipe will isolate one from the other.
This is must if you choose to squeeze the duct in place.
If copper water lines touch other metal pipe or duct, it will develop a pinhole leak. A piece of insulation on copper pipe in the picture is a good example of what to do.
 
 

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