Re: Inflatable HVAC duct valves

["Jeff Volp" <JeffVolp@xxxxxxx>]

"E. Lee Dickinson" <lee@xxxxxxxxxxxxxxxxxxxxx> wrote in message
news:dnf5tp$2js$1@xxxxxxxxxxxxxxxxxxxx
>
> If I had accessible ductwork, I'd be down on that. The large duct to feed
my
> lower floor exits the air handler straight down. Accessing it would
require
> removal of the entire air handler. It's a very tight, clean installation
> which is absolutely impossible to work on. I could knock a hole in the
wall
> it comes down through easy enough, but I have developed a deep and abiding
> hatrid of drywall work. So that's a last resort for me!
>
> I'll dig around ebay. Thanks.

The ones I saw on eBay were for branch ducts, not a main duct.  Marc is
right about backpressure.  You may have to add a barametric damper to dump
air if the pressure gets too high.  We have a dual system that only runs one
blower when the need is low.  The controller is smart enough to partially
open some dampers to prevent too much backpressure - probably by monitoring
exhaust temperature.

Ah... drywall.  I put up 115 sheets of the stuff here - mostly 12 footers.
The fun part was calculating all cuts in a spreadsheet to virtually
eliminate any waste.

Good luck with your project.  I'm convinced that an efficiently used zoned
system will quickly pay for itself.

Jeff