Hood vent 10" damper connection question

rsel04

Hi, I'm trying to install a hood vent that exhausts straight out the back through an outside wall. My challenge is that the 10" damper that connect to the hood is a full 10" in diameter and I'm unable to find a collar that fits over it. The only collars or reducers I have found are like 9.85" diameter. Ideally, I would like to connect a short 10-8 inch reducer that fits around the 10" damper. If anyone knows of a fitting that would work I would be very grateful for some guidance.

Thanks

rsel04

IMG_6279.jpg

Larry Weingarten

Hi, That damper seems to go from round to square. Is the square part what fits the hood? A thought is to get a 10" by 12" bushing to go over the damper and then continue through the wall in 12" vent pipe… or take it to a sheet metal shop where they can make something that fits correctly. May I assume you'll have a hood on the outside to prevent rain from getting in?

Yours, Larry

ps. This must be a big hood. Normally I see 7" is the vent size for residential. 🤠

rsel04

Thanks for the response Larry.

It's a 600cfm fan. Not super big so I'm not sure why it needs the 10" diameter vent. My guess is you can mount 2 fans on it for 1200cfm. It's made by Elica. Anyway, you are correct. The square side screws into the hood and round side with the damper goes towards the wall. I will have an outdoor cap with damper and screen as well. Can't understand how they expect me to connect this up but will continue researching.

Best, Rich

Larry Weingarten

Hi, I'm not sure why two dampers are needed. It might simplify things if only one were used. No doubt it depends on the fan used, but I found hood duct sizing down to six inch for moving 600 cfm. With a screen, I'd want to go bigger, but it seems you have more choices than just sticking with ten inch.

Yours, Larry

rsel04

Yes. My plan was to connect a 10-8 inch reducer to the square to round transition that came with the hood Problem is the 10" side of the reducer won't fit over the 10" side of that part. I'm now thinking they probably have a custom piece I'll need to get from them instead of being able to use standard fittings.

mattmia2

Common fittings are off the shelf but in most sheetmetal work you will have to fabricate at least some of the components. you could just use only the damper in the exhaust hood too.

rsel04

Thanks. Problem is not the 2 dampers. The fitting that connects to the back of the hood has a damper. I can easily remove that damper if I need to but that does nothing to solve the underlying issue that I still need to connect that part that connects to the back of the hood to a reducer if I want connect it to connect to an 8" outdoor cap. A reducer will not fit over the 10' round section of the part depicted in the photo above. I guess I can always create a custom collar but was hoping I could find a suitable fitting. I'll check with the manufacturer and see if they have such a fitting.

Larry Weingarten

Hi, Might a fitting like this work? If it's too big on the large side, it could be crimped (like the smaller side) and inserted, rather than placed over the adapter.

Yours, Larry

rsel04

That looks like it could possibly work if the dimensions are close to what I need. Do you have a source of where I could find something like it?

pecmsg

your issue is going from 10” to 8” in a wall cavity!

Time to get creative!

Larry Weingarten

Hi, That was just an image from Walmart. Lots of creativity available here 😉

Yours, Larry

Kaos

You have to be careful with reducer close to a damper, sometimes the reducer won't let the damper swing open.

Why not use a 10" wall cap and connect it straight to it?

mattmia2

might be an 8" damper/adapter for it too. usually the manufacturer of the hood buys the mechanical parts from broan/nutone

rsel04

I thought about going straight out with a 10" but when I saw the size of the outdoor vent it just seemed way too big. Being from north Jersey I'm also a little concerned about getting a lot of cold air coming up that 10" pipe. I have a very short distance to the outside (maybe 8 inches) so I'd like to keep it as tight as possible without impacting air flow.

Thank you all for the suggestions and feedback. I have some good ideas now. Once I have a workable solution I plan to connect things up before mounting on the wall and turning it on to make sure the dampers are behaving properly. Will post an update once it's up and running.