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Bloodman14
07-14-2017, 10:47 AM
Hey, all, I have a few HVAC blowers that I would like to turn into regular fans for shop ventilation. Do any of you have a wiring diagram that would allow me to wire them up for variable speeds without to much trouble? Thanks much.

NyFirefighter357
07-14-2017, 11:36 AM
What color wires do you have? 110v or 220v? There should be a wiring diagram on the motor. Browns go to capacitor, White to neutral for 110v Black, Red, yellow, blue? 1, 2, 3 or 4 speed? Each is a different speed. The best way would be to use a multi position switch main power in and each fan speed to it's proper terminal. If it's a 3 speed switch choose not to connect a middle speed just make sure you tape up all the connections even if not used.

jsizemore
07-14-2017, 05:15 PM
There should be a wiring diagram on the motor.

MT Gianni
07-15-2017, 12:59 AM
It won't get you a variable speed but you should be able to elect which blower speed you want.

6bg6ga
07-15-2017, 06:35 AM
I realize that everyone wants to use what they have on hand. Sometimes when you factor in the materials needed to use the blower to make some kind of stand and your time wiring it up it might be simpler to purchase a regular high output commercial type fan.

mold maker
07-15-2017, 09:25 AM
Most fans in AC units are intended for serious duty. Most stand alone fans are made for profit. There is a difference in quality and expected life.
AC fans are meant to have moderate airflow restrictions (filters and coils), and thus when the restrictions are removed, the motor load is increased by the free air flow. Adding a filter gives cleaner air and less motor load.

popper
07-15-2017, 12:57 PM
AC fans are meant to have moderate airflow restrictions (filters and coils), and thus when the restrictions are removed, the motor load is increased by the free air flow.
Inside fans are squirrel cage fans that work even with output back pressure but need the housing and probably some minor ducting. Compressor fans are blade type but still should have some shroud. Newer builder units are strictly single speed.

Grmps
07-15-2017, 06:56 PM
I use a medium sized squirrel-cage furnace fan mounted to the wall at the end of my garage set up with a high, low, off switch blowing between my casting bench and other work benches. when I want to send air to other parts of the garage I have an 8inch HVAC steel flexable elbow attached to a board that I swivel down to route the air where I want it.
I researched online for a wiring schematic. [it would help if you knew what it came out of]

MT Gianni
07-15-2017, 07:32 PM
For a room temperature duct you could use Masonite instead of tin. 4x8 sheet is around $8 @ home despot. 16"x16" duct should be all you need. Run 2x2 or lath on the inside to nail to.

Uncle Grinch
07-16-2017, 12:39 PM
Most fans in AC units are intended for serious duty. Most stand alone fans are made for profit. There is a difference in quality and expected life.
AC fans are meant to have moderate airflow restrictions (filters and coils), and thus when the restrictions are removed, the motor load is increased by the free air flow. Adding a filter gives cleaner air and less motor load.

Right on... my blower kept running hot until a buddy of mine who does HVAC work fixed it by placing a flat piece of aluminum across the input side of the blower. It needs some restriction, he said.

frankenfab
07-16-2017, 02:37 PM
Right on... my blower kept running hot until a buddy of mine who does HVAC work fixed it by placing a flat piece of aluminum across the input side of the blower. It needs some restriction, he said.

You can use an ammeter, and change the size of the metal strip until it draws the specified amount of current.

frankenfab
07-16-2017, 02:38 PM
Sam's club sells some pretty awesome squirrel cage fans for $60, last time I bought one.

SSGOldfart
07-17-2017, 08:16 PM
Most of these bowers aren't designed for continuous use,some are capacitor started and some are capacitor running. I have a couple that will shut down when they get hot,good for about 1/2 hour of run time it will restart after cooling.

Bloodman14
07-18-2017, 12:33 PM
I have no idea what they came out of, I just picked them out of some units I was given for scrap. I may just buy the commercial types and have done with it. Thanks, guys.

ghh3rd
07-18-2017, 04:35 PM
My buddy works on AC and gave me a large air handler fan. He did say that it does require some restriction so it doesn't overheat. He asked high or low speed when he wired it for me. Of course I said high.

Man that thing puts out tons of air. It will blow pictures off the wall, and roll throw rugs up. I haven't encased it yet, but need to as it could really put a hurting on someone if they mishandle it while it's running.

MT Gianni
07-19-2017, 03:32 PM
Most of these bowers aren't designed for continuous use,some are capacitor started and some are capacitor running. I have a couple that will shut down when they get hot,good for about 1/2 hour of run time it will restart after cooling.

When I did tin work one of the most requested and commonly done modifiers was to make the furnace fan run continuously. By eliminating the motor stop and start you save more than with the fan cycling on and off 5 times an hour. I have forgotten the product name that caused the fan to run at a variable speed, slow constant and faster when the heat exchanger was warm. It makes a very comfortable house.

SSGOldfart
07-19-2017, 04:17 PM
When I did tin work one of the most requested and commonly done modifiers was to make the furnace fan run continuously. By eliminating the motor stop and start you save more than with the fan cycling on and off 5 times an hour. I have forgotten the product name that caused the fan to run at a variable speed, slow constant and faster when the heat exchanger was warm. It makes a very comfortable house.

yes sir if you've got the right motor they work well, a auto transformer might be what your thinking of?