In this video, Phillip Green of PlumbersStock.com demonstrates the correct method for installing a register onto a length of cylindrical ductwork. Installing your registers correctly will help your furnace run more efficiently by preventing unecasary pressure loss. Correct installation will also help you to direct the air coming from your furnace where you need it.
Now to install the diffusers, they are an SD52-0, they have an opposed blade damper. These ones are 12x6 and I'm just going to put it right here on the duct. Figure out where it needs to go and approximately down the line and also make sure it's centered. We're going to point straight down with these because these diffusers can adjust either direction, and this is a nice long hallway. So I'm just going to put it on there and then I'm going to trace out the inside of it.
It doesn't have to be perfect, just pretty close. You can see the general lines right here, maybe trace them out a little bit better and then the flange on this diffuser will cover up any excess. Plus it has a foam, so you don't actually have to sealant it.
I'm going to use my Malco Aviation Snips, AV6, the Malco AV6.
To start the hole first I'm going to use the Malco CB, which is the cutting bit out of their hole cutter. It works really well to start a whole and then also to make the whole larger. So I have a hole started here, you just put the snips right in it and start cutting in a circular pattern, just make the hole bigger. Eventually I'll get over to the lines. You've got to be really careful because this is way sharp, you'll cut your fingers off and all.
This is the opposed blade part of this diffuser. You can basically stock a phillips-screw driver in right there and close it, I'll show you. Just like that, back open. So we're going to have it open right now. After I have it installed I can adjust these movers to go this way or this way. Since the flow of the furnace is going in this direction, I think I'll just continue it in that same direction. Got to adjust each one of them individually.
There we are, an even pattern.