Is it just me? Am I too picky?

ChrisJ

So I bought a bunch of "Air-Tite takeoffs with dampers" for the system I'm building.

They were far from air tight. Having one damper shaft just flopping in the wind in a wide open hole and the other with a lever and a wing nut. How is this considered acceptable!?



I did some thinking, and came up with this. All I need now is a bead of silicone on the seams and rivets. The abrasion resistant rubber washers fit very tight and needed to be threaded onto the shafts.

They also operate a bit nicer with the wing nuts loose as I have steel washers on the inside as well.











Thoughts?

ChrisJ

Hatterasguy said:

Observe the leakage around the 6" diameter damper plate and compare that to the effort you are making to limit airflow through a .18" hole in the side.

You'll have your answer.

No 6" damper plate here.

8" is the smallest there, the bigger one is 14".

So you're saying at 0.02" there will be very little leakage via those holes? If so, why bother sealing all of the joints that fit fairly tight?

Paul48

Maybe use Ny-locks instead of the wingnuts. I don't think you have enough thread to double nut the shaft.

ratio

I've come to grips with the occasional times I have to let my OCD come out and play.

Overdone and unashamed!

EBEBRATT-Ed

I used to work with a guy who was a great mechanic. His motto was "If it's worth doing it's worth overdoing"

But, he drove the rest of us out of our minds!

If it makes you happy, do it!!

But don't expect everyone else to do it

ChrisJ

I was told duct leakage would be one of my greatest concerns in an attic.

So, I'm fixing that.

ChrisJ

Paul48 said:

Maybe use Ny-locks instead of the wingnuts. I don't think you have enough thread to double nut the shaft.

I know where you're coming from, but I don't think it's an issue only because I plan on loosening the nuts before moving the damper. Tightening them locks it in place nice.

I'm really hoping once they're set, they're set. Knowing me, probably not, but I can hope.

Larry Weingarten

ChrisJ, You might like this club! http://ring4club.com/ They are over the top duct leak sealers. I know a few of them

Yours, Larry

EBEBRATT-Ed

Duct leakage. Not only do you lose cold air to the attic but every 1 cfm lost to the attic is made up by 1 cfm of outdoor air infiltration leaking into the conditioned space.

I learned this the hard way. I once went on a call on a temperature and humidity controlled room (a lab) which was built inside of an unconditioned factory.

They complained about high humidity. The air conditioner worked fine couldn't find anything wrong with it..spent a few hours checking it out.

Finally crawled up on top of the lab and one of the flex ducts had pulled off a supply diffuser. Didn't think much about it just reconnected it. Then after thinking about it that air lost to the "factory" had to be replaced by air infiltration from the factory to the lab.

Almost immediately the humidity snapped back to normal

ChrisJ

EBEBRATT-Ed said:

Duct leakage. Not only do you lose cold air to the attic but every 1 cfm lost to the attic is made up by 1 cfm of outdoor air infiltration leaking into the conditioned space.

I learned this the hard way. I once went on a call on a temperature and humidity controlled room (a lab) which was built inside of an unconditioned factory.

They complained about high humidity. The air conditioner worked fine couldn't find anything wrong with it..spent a few hours checking it out.

Finally crawled up on top of the lab and one of the flex ducts had pulled off a supply diffuser. Didn't think much about it just reconnected it. Then after thinking about it that air lost to the "factory" had to be replaced by air infiltration from the factory to the lab.

Almost immediately the humidity snapped back to normal

Very good point, though in my case my attic isn't vented.
It's kind of an indoor space, kind of not. What I want is to insulate between the rafters in the future, if I ever get the money to do it and essentially turn it into a conditioned space.

Whatever happens, I need to be careful because I do not have any moisture issues up there in the winter currently and I'd like to keep it that way.

Fred

It should be vented. Any good roofer will tell you without vents, roof shingles will begin to curl over time.

ChrisJ

Fred said:

It should be vented. Any good roofer will tell you without vents, roof shingles will begin to curl over time.

That's a new one on me Fred.
Roof is 10+ years old and nothing curling. Just cheap asphalt shingles.

I have no intention of venting the attic to be honest. There are plenty of properly insulated and designed unvented attics out there.

As far as I knew, the primary reason for venting an attic was to prevent condensation.

Gordy

Fred said:

It should be vented. Any good roofer will tell you without vents, roof shingles will begin to curl over time.

That's BS pounded into the roofers thick skull by shingle manufacturers. Keep that thought then find a shingle manufacturer who tells you specifically what temp is to high in the attic . You won't. That's so they can say your warranty is denied because of poor venting.

If that is the case then making the attic part of the envelope, and moving the insulation detail to the roof deck like recommended will create big issues, and it doesn't.

Gordy

Air tight has a whole new meaning with fa systems.......

njtommy

I'm pretty sure your just too picky @ChrisJ.

Your pickiness is just like my indecisiveness. lol

Steve Minnich

@ChrisJ - Both?

Abracadabra

I looked at the title... then checked who the OP was and thought to myself... yep...

EBEBRATT-Ed

hehehehe

Gordy

ChrisJ said:

So I bought a bunch of "Air-Tite takeoffs with dampers" for the system I'm building.

They were far from air tight. Having one damper shaft just flopping in the wind in a wide open hole and the other with a lever and a wing nut. How is this considered acceptable!?



I did some thinking, and came up with this. All I need now is a bead of silicone on the seams and rivets. The abrasion resistant rubber washers fit very tight and needed to be threaded onto the shafts.

They also operate a bit nicer with the wing nuts loose as I have steel washers on the inside as well.











Thoughts?

For the manufacturer that's a pretty hard detail to get perfect. You have to consider deformation of the pipe from production, packing, shipping, and installation. Then be operable with out binding up. Even though it should be a balance check, and that's the last it will move in most systems.

Your method is fine. The only thing I can think of is the rubber washers dry rotting over time in a hot environment like an attic. Other than that just the tedious work to implement the fix.

Will it make much of a noticeable difference. Probably not. Will you ever stop thinking about it if you don't bring it up to your standards deffinetly not

Solid_Fuel_Man

I've always been of the thoughts that vented attics were mainly to prevent ice dams in winter.

@ChrisJ go for it, everything that helps, even if it's 1% is money saved! I tend to overthink/do most things as well.

Gordy

The goal in unconditioned attics is to maintain as close to outdoor temperature conditions as possible. To prevent ice damming, and condensation from vapor entering the attic from the conditioned space?

ChrisJ

@Gordy fiber re-enforced neoprene rubber washers.
I assumed they should hold up fairly well in the attic.

But, your comment made me think about my idea of using foam tape as a gasket on the air handler. Silicone may hold up, but the typical cheap stuff likely won't.

Problem is that silicone tape is expensive, so I'll have to think about it. I liked the idea of a gasket rather than RTV or tape.

ChrisJ

Also,
@Gordy I'm not really attacking the manufacturer in this thread. They all appear to be made this way, it's normal.

Not to mention the product they give for the price.

However, some rubber washers don't cost much.


If I followed @Solid_Fuel_Man 's way of thinking, I wouldn't even need to seal the duct work. It would just leak into a conditioned space. Zero loss.

Gordy

Well the attic isn't living space. You want your conditioning in the living space. Trying to keep equipment as close to conditioned as possible with little energy.

Okay you said rubber, but fiber reinforced neoprene much better.

I would do gasket material instead of silicone. I think you will find it easier to assemble the parts, and cleaner. Once assembled you could always hit it with a little silicone here, and there in areas you may have concerns. Smell of silicone may linger in the ductwork also.

ChrisJ

Gordy said:

Well the attic isn't living space. You want your conditioning in the living space. Trying to keep equipment as close to conditioned as possible with little energy.

Okay you said rubber, but fiber reinforced neoprene much better.

I would do gasket material instead of silicone. I think you will find it easier to assemble the parts, and cleaner. Once assembled you could always hit it with a little silicone here, and there in areas you may have concerns. Smell of silicone may linger in the ductwork also.

I was talking about silicone gasket. The gasket I have on my monitor top is soft black silicone. Works well, but dust sticks to it like a magnet.

When I buy rubber washers, or gaskets I generally stick to silicone, Neoprene or Buna.

Steve Minnich

@ChrisJ - If you want to seal the ductwork to most current standards, you'll need to use duct mastic and/or UL181 foil tape.

ChrisJ

Stephen Minnich said:

@ChrisJ - If you want to seal the ductwork to most current standards, you'll need to use duct mastic and/or UL181 foil tape.

I had been planning on clear silicone to seal every joint and seam. Rumor on the streets is this what is approved for use in clean rooms. That's not why I chose it, but, was nice to know.

But now that I'm digging into it, I may go with mastic due to cost and effort.

I'll use tape for the insulation vapor barrier of course.

Right now on the problem solving blotter is what to do with these.



They come with a "plaster flange" on them, that is a 1/2" up from the opening. This causes a big problem for me as they are going in plaster ceilings and that flange won't sit flush against the wood lath, and the 1/2" that sticks past it won't reach all the way to the finished side.

I pulled the flange off which was easy enough and I'm thinking about mounting them in just like this with the front flush with the ceiling. Next, filling around them in the attic with spray foam and then finishing the gap with something, don't know what yet though. Joint compound would work good enough and could be painted. White paintable caulk could also work.

The gap would of course be covered by the diffuser anyway, but I want it sealed and respectable looking regardless.

The seams in the box will of course be sealed before installing and the box will be insulated with R8 or better.

ratio

Duct butter, AKA mastic as mentioned above. Way better seal than foil tape for most/all uses IMHO.

ChrisJ

ratio said:

Duct butter, AKA mastic as mentioned above. Way better seal than foil tape for most/all uses IMHO.

Do you use mesh with the mastic, or just mastic alone?

Also, any specific brand, or formula you recommend? I've seen many out there and my only assumption was what Home Depot has is likely crap. I could be wrong there too, though.

Steve Minnich

@ChrisJ - remember the pic I sent you of the boot "ears"? Those can be made to any size/depth very easily on a small brake or a bench type bar folder.

Steve Minnich

Give me the specs you want and I'll make them and send them to you. You pay for the freight. That's it.

My email address is sminnich@minnichmech.com.

ratio

I've never used mesh with it, but it would probably be a good idea. As for brands, I think we just get whatever the supply house carries when we call for a stock order. If the system isn't pressurized, you can lay it on as thick as necessary to seal the gaps—it just takes longer to dry. I'm sure there's a limit to how big a void you can fix with it though.

I've actually shinnied down three stories worth of ≈ 60" x 120" medium pressure duct to seal it from the inside out. Put gallons of butter in it, but at the end I wouldn't want to be in that duct without the fan moving air.

I was not happy about having to do that, BTW. Words were said.

ChrisJ

Stephen Minnich said:

@ChrisJ - remember the pic I sent you of the boot "ears"? Those can be made to any size/depth very easily on a small brake or a bench type bar folder.

Hi Steve,
Yep I remember, but for some reason I thought they were backwards?

This is what I came up with, and may be exactly what you had shown me, I can't remember.





I'll shoot you an email.

ChrisJ

@Stephen Minnich
Found it.




This is essentially what all of the boxes came with, but I want the ear on the finished side of the sealing. That's what makes sense in my mind. Maybe I'm being stupid? It's very possible especially on this subject.

Solid_Fuel_Man

> @ChrisJ said:
> If I followed @Solid_Fuel_Man 's way of thinking, I wouldn't even need to seal the duct work. It would just leak into a conditioned space. Zero loss.

Well that is only if 100% of the equipment is in the conditioned space. That includes ductwork and/or piping.

Steve Minnich

@ChrisJ - by having the metal on the finish side has no upside. Having it on the unfinished side gives you a great means of screwing in your register or grill, creating a tighter seal.

ChrisJ

Square ceiling box without flange is screwed into framed opening using drywall screws. White paintable caulk is used to seal the gap around the ceiling. Aluminum diffuser is screwed into framing around box through plaster ceiling.

The screws through the box as well as all seams will be sealed using clear silicone.


Am I over thinking this, probably.
But I like having a plan.

Gordy

What's your tactic for making a nice cut through the plaster, and lathe?

EBEBRATT-Ed

@ChrisJ , that's as good or better than any other method.

Not to make it more picky but you could glue 1/2" duct liner or 1/2"armaflex to the inside of the box to prevent condensation.

Just curious, is your drawing in Visio??

Plaster & lathe can be tough to cut with a sawzall can shake it loose and break some plaster. Suggest a grinder with a cutting disk and just use a jab saw on the corners if needed.

Gordy

Rotozip with a tile bit. Set the depth to cut only the plaster then switch bits to cut the lath. A bit messy, but makes a nice hole with out busting the lath lose from the plaster. However it takes a little skill to master the rotozip.

Fred

I have a Dewalt power cut-out tool and use a Roto-Zip Dura-cut bit. That works great for smooth, straight cuts. The Dura-Cut bit is designed for Plaster and lathe cutting.