I have a horizontal Goodman furnace and evaporator coil installed, and I want to know what kind of bracket I can use to connect the two. The installer did a bad job and used tape and mastic to connect the units instead of connecting them with brackets as stated in the installation manual (even states that tape and mastic is improper installation). There is a half inch gap on one side between the units. I need to find brackets to attach the two units together. The install was 8 years ago with my builder, and the brackets are long gone. The installer only has a 2 year warranty. Goodman won't sell me brackets unless I'm licensed. No one seems to sell them online either.

Can I just use galvanized metal straps from the big box store to screw the furnace and evaporator coil together? This is the evaporator coil https://www.alpinehomeair.com/viewproduct.cfm?productid=453057306. It also includes the manual for the install and a picture of the brackets is in the "View All Photos."

enter image description here

  • Can you provide a photo of what you have – Ed Beal Feb 8 at 19:26
  • Please provide a photo. Tape shouldn't be used for anything structural but it should be used to prevent air leakage as much as possible. Foil tape is usually quite terrible and will be useless within a year so I highly recommend foil-mastic tape. – MonkeyZeus Feb 8 at 19:52
  • Fwiw, I have an upright Goodman furnace with a coil sitting on top of it and there were no instructions for mechanically attaching one to the other. However, the plenum attached to the top of the coil quite well. – MonkeyZeus Feb 8 at 19:56
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    I was looking at the manual for the coil. alpinehomeair.com/related/IO-285L.pdf. It says "3. Using the hardware and brackets provided, attach the coil to the furnace then attach the plenum to the coil (Figure 3)". They probably stay together better in a upright configuration. Mine is hanging from the rafter and sits on cinderblocks, so it a can move around a bit. – hjohn06 Feb 8 at 22:29
  • The "brackets provided" would've just been two lengths of sheet metal, ~2" wide and a length an inch or so short of the depth of the unit. Do not screw into the drain pan of the coil. If you lost them, they may still be attached to the inside of the furnace. Notice there was tape and then mastic. Do not mastic the machine; pita to service it. Bracket, tape, then mastic. Or just bracket then tape. – Mazura Feb 9 at 3:06

I believe you misunderstood the instructions:

enter image description here

Sealing up the joint with tape/mastic after installing the bracket is part of the instructions. The installer omitted the bracket for whatever reason and just sealed it up. Could have been for noise reduction purposes as the other answer mentioned. Tape/mastic is not structural, it is all about minimizing CFM loss and making sure your conditioned air reaches its intended destination.

I don't know if there is anything particularly special about the missing bracket but you should be able to buy some sheet metal (28 or 26 gauge) from a local home improvement store or sheet metal shop and just fabricate your own bracket.

You need some sheet metal, tin snips, zip screws (1/2 inch self-tapping screws), 1/4 inch drive bit, and a drill. Just try to copy what is presented in the manual and make note of my image below. Avoid hitting the stuff noted in red.

If you want then add a bracket to the bottom and back side as well. Do not add a bracket to the front because those doors need to remain accessible.

enter image description here

  • I was thinking the statement and the diagram might be unrelated. Was wondering how it would keep the air from leaking otherwise. – hjohn06 Feb 9 at 23:38
  • @hjohn06 Good luck and I hope to see an updated picture with your final solution :) – MonkeyZeus Feb 10 at 14:29

it is normal to have a flex fitting between the furnace and ductwork. I say normal because that’s how I was taught and what I usually see. This really reduces ductwork noise.

I use a vinyl coated fabric reenforced material clamped to the duct create a flex bulge and clamp to the furnace.

I would use caution creating a solid connection to the furnace if you have metal trunks think of a base drum that’s what the ductwork may sound like especially on startup and stop as the fan motor spins up and down there is usually a speed where it is out of balance and the noise can be irritating.

You can use metal straps to connect them but I would recommend a flexable one. (Not tape) use caution where you use screws make sure you won’t go through and hit wires, refrigerant lines, exhaust. You get the idea use caution if you strap.

  • Thanks for the tip. The whole thing is floating (not sure what the right term is). It has metal straps connecting from the rafters and sits on cinder blocks. The positions they have settled into leaves a half inch gap one side. I'm not sure if any fabric would hold the two together, or maybe just leave the gap as is. But also seals up the panel cover to the evaporator. – hjohn06 Feb 8 at 20:06
  • Yes this is what I am saying leave the gap. I broke loose a friends that he asked me to look at, got 1/4” gap and sealed with cloth reenforced vinyl and he was ecstatic about the noise reduction. I can’t believe how sloppy your guy was but I would bet he did have a gap. Vinyl coated fabric is what I use I know guys that use rubber , silicone sheeting and one guy that bought a truck tarp at an auction and said when he runs out of that he would retire. The few solid connections I have seen were DIY jobs I thought, but I would have called yours a diy. So I would leave a gap but seal each side. – Ed Beal Feb 8 at 20:34
  • I'll take a look at that. What kind of product are you using with the vinyl? Mastic? – hjohn06 Feb 8 at 22:39
  • I don’t use a mastic I use a metal bar and wrap the material around the bat and put 3-4 screws into it to hold it to the duct. If single sided I put the vinyl on the inside I keep from adding anything that could promote mold growth inside. I get the fabric at joann’s a fabric store that has all kinds. The last few times the stuff they had was double sided. It’s kind of like rain jacket material or that’s what I thought when I first started getting it. It doesn't take much about an 8” strip all the way around . Where the ends meet roll the 2 layers together a screw on either side holds a seal – Ed Beal Feb 8 at 23:31

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