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Baffle Box & HVAC: duct board, flex duct, motorized damper

Posted: Tue Aug 22, 2017 6:27 am
by muze
Hi,
I'm starting to build my baffle boxes for my fresh air system, as well as plan my HVAC system. I had some materials questions, for those who have done this before.

I couldn’t find Johns Manville Superduct RC online, but I did find the below Johns Manville 1” duct board insulation. Would the below product be suitable for lining the inside of the baffle boxes?
https://www.amazon.com/Duct-Insulation- ... 4In+x+48In

Would the below rubber duct hose (6" size), be suitable for connecting the penetrations between the inner wall and outer wall?
https://www.amazon.com/Flexadux-Thermop ... ubber+duct

I'm planning to use the Fantech FG6 inline fan, as people have had good experiences with this fan, as well as the Fantech FB6 filter box. I will also use the Fantech WC15 variable speed controller, and even though people have complained that it introduces more noise when reducing the fan speed, I figured that my baffle boxes will attenuate that extra noise.

Does anyone have recommendations for a motorized damper, for the 6" supply/return ducts? I would like to have the 6" circular opening to the outside closed by default, and then powered to open when I turn on the fresh air system.

Thanks for your help!

- Alex

Re: Baffle Box & HVAC: duct board, flex duct, motorized damp

Posted: Mon Sep 11, 2017 10:01 am
by Soundman2020
Alex, you have posts spread all over the place! It's really difficult to follow your build, since you have created half a dozen threads, each one asking about a different aspect of your build. It would be MUCH better to have one single thread about your entire build, and keep all your posts in that.
I couldn’t find Johns Manville Superduct RC online,
IS there a reason why you wanted that specific product? There are several duct liners that you could use.
Would the below rubber duct hose (6" size), be suitable for connecting the penetrations between the inner wall and outer wall?
No- Most definitely not! Did you read what it says about what that is actually meant for? "For Use With Dust, Chips, Shavings". It's meant for a shop vac system. Not for air that you intend to breathe...

Use only proper HVAC flex duct that is specifically designed for this purpose.
Does anyone have recommendations for a motorized damper, for the 6" supply/return ducts? I would like to have the 6" circular opening to the outside closed by default, and then powered to open when I turn on the fresh air system
Then you are looking for the wrong product. That's not what motorized dampers are meant for. They are not designed to stop back-drafts. They are designed to regulate air flow in an HVAC system. If you want to stop back-drafts on your exhaust outlet, then use a proper automatic back-draft damper. There most common ones are butterfly and louver, but there are also other types.

Never use the wrong product for the wrong application!


- Stuart -