Furnace Return Air Plenum Fabrication

This is just one of many ways to form a return air box or plenum for an electric air handler to sit upon. The box is required in most cases to ensure full unrestricted air flow through the evaporator (or indoor coil) , which may be an "A' coil style, (upright or inverted) or a slant coil. There are some that allow air to enter on the side of a slant coil, but more and more the manufacturers are designing them to be adaptable from left side, right side or a horizontal application. Entering the bottom by use of a return air plenum box eliminates that decision, plus a lot of manufacturers are making air handlers shorter to give the installer more working height on furnace change outs.
When you are figuring out the height of your box, the main thing to consider is whether or not there is a convenient and workable factory filter rack in the bottom of the air handler or if you have to provide a slot of your own in the return air drop. The minimum height I use is around 17" because the normal size filters I like are 16" in height. It is a good idea to try to always make a filter rack if required in a fashion which will allow standard filters to be utilized. Nothing is worse than having to run down special order filter sizes that are not normal stock items because you didn't take the time to adapt the factory slot or fabricate your own slot to standard sizes.
I didn't record the awkward folding of the three sided wrapper because my shop is very crowded. The best set up for myself is a full length table that is four feet wide right behind the brake to support the oddities that have to be worked with from time to time. If not supported the long pieces can flip down to the floor and place an awful kink right where you don't want it in a piece of metal.

The box and pan brake does come in handy for things other than boxes and pans. Without having the versatility of the removable jaws, the second quarter inch 90 degree bend would have to be folded over then folded back by hand in order to fold in the sequence shown in the video.
The little reinforcement corners make a great addition to strengthening an otherwise floppy box. Of course by the time the air handler is place on the box, it will scrunch down and support much more than the weight of a residential/light commercial air handler. But I still like to make them sturdy. Back when I got started in the mid-70's some of the boxes were made of 22 guage and a lot of the joints were soldered together !! But you have to remember the weight of the machines they were asked to support was much heavier and much larger physically than those produced today. That would this day and time be considered "overkill" as far as strength or sturdiness is concerned as well as a waste of material and labor. So all things evolve.... humankind itself as well as the things we create.
So I hope you enjoyed the video as that was its intent. I don't do instructional videos or promote them as such, but if you are lucky enough to pull a grain or two of information that may help you in your daily work, feel free to take it with you....but make sure you improve it and make it your own and don't hesitate to pass it on to someone else that may be interested. Information is not ours to keep...its ours to share. And also remember that there are as many ways to perform a function as there are people to do it !!

Видео Furnace Return Air Plenum Fabrication канала Tractorman44