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is it ok to feel air where the cased coil meets furnace?

Posted by cindywhitall (My Page) on
Wed, Oct 3, 12 at 14:31

I doubt this is "ok" My unit is a cased coil that sits on top of what I call the "furnace". The supply duct comes out the top of the coil. I feel air blowing in about a 3-4 inch section where the coil meets the furnace and at the top of the coil where it meets the ductwork. It may be from the coil panel itself at the top, I can't tell for sure. I had pointed out the air leaking around the bottom of the coil when they came on day 2 of the install. They responded that they weren't finished yet and I said "ok". They did apply some silver caulk stuff (mastic?) in the area of the leaks and I didn't really check it again until today. On that first day I hadn't noticed it at the top, just on both sides of the bottom.

I want to know how unacceptable this is before I complain....don't want to be a serial complainer but....

btw, I made this a separate thread in case some knowledgable folks aren't following my other thread. This one should be pretty cut and dry. THANKS!

Follow-Up Postings:

RE: is it ok to feel air where the cased coil meets furnace?

"don't want to be a serial complainer but.... "

Too late!

Some amount of leakage is not that bad, I would think. That's what duct tape was invented for.

RE: is it ok to feel air where the cased coil meets furnace?

The bottom of the coil where it sits on top of the furnace should be sealed with a silicon caulk. The connection at the top of coil to the duct work should be sealed with duct mastic.

This should be fixed if the leakage is signicant. It is not so terrible since your furnace is in the basement.

RE: is it ok to feel air where the cased coil meets furnace?

I'd use mastic tape. don't think I've ever
used duct tape on hvac jobs.
hardcast brand 1402 mastic tape is an
excellent product. seals to many different
surfaces as long as they are clean & dry.

all equipment junctions & equipment to plenums should
be mastic sealed.

best of luck.

RE: is it ok to feel air where the cased coil meets furnace?

A small amount of supply air leakage through gaps between coil/furnace is not an issue at all. Of course it should be sealed as best as possible.

air leakage

Consider how much your existing supply air ducts are already leaking and I'm betting the small amount of leakage where the coil meets the furnace is minimal, relatively speaking. There is a lot of pressure that close to the blower. I prefer to seal it with paint-on mastic. The caulk (silicon?) they used on your system (shown in pictures on another thread) should be fine also if applied properly.

RE: is it ok to feel air where the cased coil meets furnace?

They are coming Tuesday. My guess is they will use the same caulk stuff. It is leaking in 2 places and I don't think they are small leaks as they air seems to hit my entire palm when I hold it a few inches way, and in close.It's not like it's a 1/2 gap. It's in the basement, so it seems like a waste to let it leak there when I read so much on here about seal seal seal and seal some more! I was frustrated when I noticed it because I didn't want to have them have to come back out, and quite frankly, it SHOULD HAVE BEEN DONE RIGHT the first time! I thought I hired one of the best companies:(

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