Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 08-20-2011, 12:37 AM   #1
Member
 
Join Date: Aug 2011
Location: SE Michigan
Posts: 100
Share |
Default

How to patch around a 2" x 4" hole in back of furnace


First time doing anything with a furnace. I can't imagine this is typical, but there's a hole in the back of my furnace that's around 2" x 4", but I haven't measured to be exact. It's in the basement, and luckily I can easily get to each side. A bunch of air leaks out of it when the A/C runs (and I assume heat would also). Looks like a long time ago, someone tried patching it with some type of spray foam.

What's the proper way to plug this leak? I do have quite a bit of Great Stuff around for other projects, but I'm thinking that wouldn't do much better than this black stuff did.

Thank you so much - I think plugging this one leak alone will save a lot of energy every month.


darlingm is offline   Reply With Quote
Old 08-20-2011, 01:24 AM   #2
Retired from the grind
 
gregzoll's Avatar
 
Join Date: Dec 2006
Location: Midwest - Central Illinois
Posts: 14,114
Default

How to patch around a 2" x 4" hole in back of furnace


A piece of sheet metal works. Just have to secure with screws, then tape the seams.

gregzoll is online now   Reply With Quote
Old 08-20-2011, 02:00 AM   #3
Member
 
JJboy's Avatar
 
Join Date: Oct 2010
Location: Austin - Texas
Posts: 1,402
Default

How to patch around a 2" x 4" hole in back of furnace


Quote:
Originally Posted by gregzoll View Post
A piece of sheet metal works. Just have to secure with screws, then tape the seams.
after doing all, you can use mastic for the final finish.
__________________

**Always kill the power ** Hot air rises, but heat will always move from higher to lower temperatures. ** Real man shoot in manual. ** If it ain't grounded, it ain't dead.
JJboy is offline   Reply With Quote
Old 08-20-2011, 02:29 AM   #4
Retired from the grind
 
gregzoll's Avatar
 
Join Date: Dec 2006
Location: Midwest - Central Illinois
Posts: 14,114
Default

How to patch around a 2" x 4" hole in back of furnace


Yes, that way works also.
gregzoll is online now   Reply With Quote
Old 08-20-2011, 06:50 AM   #5
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 25,052
Default

How to patch around a 2" x 4" hole in back of furnace


Thumb dumb. No worry of screws going where you don't wan t them to be.
beenthere is offline   Reply With Quote
Old 08-20-2011, 08:08 AM   #6
Member
 
concretemasonry's Avatar
 
Join Date: Oct 2006
Location: Minneapolis/St. Paul, Minnesota - Latitude 45.057 Longitude -93.074
Posts: 3,751
Default

How to patch around a 2" x 4" hole in back of furnace


You are really not be losing warm or cold air, but not controlling the flow as much as you want because the basement is still in the livable space.

Dick
concretemasonry is offline   Reply With Quote
Old 08-20-2011, 08:24 AM   #7
Member
 
Join Date: Aug 2008
Posts: 130
Default

How to patch around a 2" x 4" hole in back of furnace


A piece of sheet metal and some of that shinny silver refrigeration tape (available at HD). Don't use screws.
kb3ca is offline   Reply With Quote
Old 08-20-2011, 05:13 PM   #8
REP
Member
 
Join Date: Jul 2011
Posts: 615
Default

How to patch around a 2" x 4" hole in back of furnace


What I would do is use a piece of sheetmetal cut out so as to cover most of that hole.I perssonally do not like to have sheet metal touch those copper lines because of vibration either digging into the copper or creating harmonics.That said I would actually seal what ever leak there will be with thunb gum.
As for the sheetmetal with or without screws it dosen't matter as long as you are very carefull not to punture the copper lines or the coil that they are attached to. I would use small 1/2 inch zip screws and RTV on the sheet metal to form a gasket.
What you are lookingt at are the suction line (the big line covered with black foam) and the liquid line attached to where I assume the metering orfice is located.(that big brass nut)
Making sure the existing metal is scraped and clean before attaching the sheetmetal patch is also important.
Good luck
REP is offline   Reply With Quote
Old 08-20-2011, 06:53 PM   #9
Member
 
Join Date: Aug 2011
Location: SE Michigan
Posts: 100
Default

How to patch around a 2" x 4" hole in back of furnace


Thanks for everyone's responses. I'm going to go the route of sheet metal without screws. REP, also thanks, because vibrations/harmonics would drive us nuts!

Few follow-up questions.

Since looking at it a bit more today, I've noticed the liquid line is dripping water at a slow rate when the A/C is blowing. It seems to be leaking at that yellow'ish nut.

1 - Is the liquid running through that line just water, or does it contain freon?

2 - What's the best way to stop that leak?

3 - Haven't worked with thumb gum before. If I cut the sheet metal so it blocks most of the hole but doesn't touch either line, would Fire Block Great Stuff be just as good to use as thumb gum? I already have that, but could buy thumb gum if that was better. I'm sure a consideration is how easy whatever I do is to remove, if it needs to be some day. Not sure how removable thumb gum & Great Stuff area.

If I cut the sheet metal so it blocks most of the hole but doesn't touch either line,
darlingm is offline   Reply With Quote
Old 08-20-2011, 08:22 PM   #10
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 25,052
Default

How to patch around a 2" x 4" hole in back of furnace


Don't use great stuff, it won't come off easy. thumb dumb it.
beenthere is offline   Reply With Quote
Old 08-20-2011, 09:52 PM   #11
Member
 
Missouri Bound's Avatar
 
Join Date: Apr 2011
Location: Almost Arkansas
Posts: 2,764
Default

How to patch around a 2" x 4" hole in back of furnace


What you are probably seeing is the pipe sweating, the suction line would be cold, and condense. If you cut a piece of sheet metal in half, and install it from the inside, it will naturally be held against the furnace. A little mastic or perhaps duct seal around the pipe may work. It should be dry when you apply it.
Missouri Bound is offline   Reply With Quote
Old 08-21-2011, 01:02 PM   #12
REP
Member
 
Join Date: Jul 2011
Posts: 615
Default

How to patch around a 2" x 4" hole in back of furnace


First what is running in those lines is freon.In through the small line and out in the large line.
Second the moisture you see feel on the brass nut is water that has condensed on the coil that the lines are connected to.
That is not a "leak" it is what happens when hot humid air hits something that is cold (i.e. that a/c coil)
Thum gum is like a piece of clay or a very dense play dough.It won't be any good for holding that small piece of sheetmetal to the metal plenum,but it will be able to fill the small gap between the copper lines and that small piece of metal.That is why If I did it I would use screws to hold that small piece of sheetmetal to the plenum.
Good Luck
REP is offline   Reply With Quote
Old 08-21-2011, 10:06 PM   #13
Member
 
hvaclover's Avatar
 
Join Date: Oct 2008
Location: Suburbs of Detroit Mi
Posts: 3,704
Default

How to patch around a 2" x 4" hole in back of furnace


I am a little concerned about that yellow coloration on the LL nut holding the piston. Is that leak trace dye?
__________________
Just slow, not stupid.
hvaclover is offline   Reply With Quote
Old 08-21-2011, 10:12 PM   #14
Member
 
hvaclover's Avatar
 
Join Date: Oct 2008
Location: Suburbs of Detroit Mi
Posts: 3,704
Default

How to patch around a 2" x 4" hole in back of furnace


I don't think that is a good idea. There is enough air coming out that line set hole to make a difference in other part s of the home
__________________
Just slow, not stupid.
hvaclover is offline   Reply With Quote
Old 08-21-2011, 10:16 PM   #15
Member
 
hvaclover's Avatar
 
Join Date: Oct 2008
Location: Suburbs of Detroit Mi
Posts: 3,704
Default

How to patch around a 2" x 4" hole in back of furnace


Quote:
Originally Posted by REP View Post
First what is running in those lines is freon.In through the small line and out in the large line.
Second the moisture you see feel on the brass nut is water that has condensed on the coil that the lines are connected to.
That is not a "leak" it is what happens when hot humid air hits something that is cold (i.e. that a/c coil)
Thum gum is like a piece of clay or a very dense play dough.It won't be any good for holding that small piece of sheetmetal to the metal plenum,but it will be able to fill the small gap between the copper lines and that small piece of metal.That is why If I did it I would use screws to hold that small piece of sheetmetal to the plenum.
Good Luck
Rep you are right. Thumb Gum is not made to close openings that size. Only used for sealing the line set opening of the line set in to the plenum.

__________________
Just slow, not stupid.
hvaclover is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Water Inside/Around American Standard Furnace michrob HVAC 8 12-08-2011 03:51 PM
Can I use a drywall patch to cover a hole where an old outlet box used to be stephroberson Drywall & Plaster 4 09-28-2010 07:25 PM
Problem Patching Large Drywall Hole FuLLTiLT Drywall & Plaster 5 11-21-2009 09:42 PM
I hope I don't have to tear down the ceiling brds16 Carpentry 9 04-30-2005 10:16 AM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.