Furnace Blower as Fan

[Kapacitor]

Hi everyone,

I am trying to stay cool... got a furnace blower from a family member and want to convert it to a portable room/garage fan similar to the many videos I see on YouTube about doing this. The problem is the blower motor I have confuses the heck out of me. Can ya'll please direct me on how I can wire this motor to a 3-wire plug to allow me to 'plug and cool' in any room I take the unit into? Here are some pics of the motor.

Thanks in advance.

 

[Bert_]

It's an ecm motor. You will have a lot easier time if you can find an older permanent split capacitor motor.

 

[The Cobbler]

I think you may be missing a capacitor or 2...and maybe a controller

 

[Gutman]

It can be done, however, since it's an ECM (electronically commutated motor), it's a little more complicated.

I went through this drill about 4 years ago.

Not sure how to post a link to my thread, but search for:

"Re-purposing HVAC Blower; Need Some Help"

 

[The Cobbler]

It can be done, however, since it's an ECM (electronically commutated motor), it's a little more complicated.

I went through this drill about 4 years ago.

Not sure how to post a link to my thread, but search for:

"Re-purposing HVAC Blower; Need Some Help"

Re-purposing HVAC Blower; Need Some Help

I’m re-purposing a squirrel cage blower fan and motor, salvaged from my air handler after upgrading my HVAC system, for use as a blower in my shop. Although I did something similar many, many years ago, it was back when I was a little smarter and electric motors were much simpler with a just a...

www.garagejournal.com

 

[chinboys]

You might find a generic ECM controller that will communicate and power this motor blower.
But why?
You could buy a 18 or 24 inch Dia 110 v fan for a lot cheaper than the above.

 

[scooterbum46]

If you succeed in getting it running (or find an older type), be sure to devise some type of restriction on the output opening (I use old license plates) and tune it with an amprobe. Those squirrel cage fans need a restrictor or they'll try to move more volume of air than the motor can handle. One of the ones I use will draw 14 amps if unrestricted, after "tuning" (adjusting how much area the plate is covering) it drops to a little over 7 amps and runs much cooler. Keep in mind in normal use, they're pushing a column of air into a duct system..

 

[Kapacitor]

In picture 2 (8024) I have the base of the unit taken off. Is it possible to connect those three wires to a 3-wire plug and it will work or will that be a bad day?

 

[Gutman]

Not sure. Maybe. Maybe not.

Not sure what version motor you have, compared to mine, but I walked through what I did and The Cobbler was gracious enough to link my thread.

Looking at the 5 pin plug of your first pic, I'm speculating that your motor was setup for 120v, as pins 4 and 5 are jumpered together. Main power (120 v) comes from the black and white wires to pins 1 and 2. If there were no jumper, then the motor would need 240v. I don't know where your 3 pin connector inside your motor leads back to.

The 16 pin plug provides 24v control power from your hvac system. Things like motor size, time delay soft start, operating speed, etc. are determined by 24v signal provided from your hvac system. If I recall, some of those settings were made by setting dipswitches or jumpers on the hvac control board. If you look at my wiring schematic, you can see the purpose of the various wires into the 16 pin connector. I never attempted operation with just 120v or 240v, as my hvac guy told me the motor would need control power to run.

If your three pin connector is the only wiring running from the bottom end to the motor end, it may work. Just not sure what default settings like speed or soft start delay might be.

Let us know what you discover.

 

[American Locomotive]

The power to the motor are the black and white wires. Green is ground. Do not try to hook power up into that internal 3 wire connector inside the motor - you will blow it up.

It is an ECM motor - electronically controlled. The control signals are the big plug with 5 wires. These motors are unfortunately not universal, and can programmed to work in a bunch of different ways by the manufacturer. Sometimes they're setup just as on/off, sometimes they're setup as 3 or 4 specific speeds (and a certain wire enables each speed), other times they variable speed and use a 0-10v voltage to control speed. Sometimes they're variable speed but use PWM (digital) to control speed.

Is there a wiring diagram of the original furnace attached the blower, or is there any way you can get the model number of the furnace it came out of?

 

[Kapacitor]

The power to the motor are the black and white wires. Green is ground. Do not try to hook power up into that internal 3 wire connector inside the motor - you will blow it up.

It is an ECM motor - electronically controlled. The control signals are the big plug with 5 wires. These motors are unfortunately not universal, and can programmed to work in a bunch of different ways by the manufacturer. Sometimes they're setup just as on/off, sometimes they're setup as 3 or 4 specific speeds (and a certain wire enables each speed), other times they variable speed and use a 0-10v voltage to control speed. Sometimes they're variable speed but use PWM (digital) to control speed.

Is there a wiring diagram of the original furnace attached the blower, or is there any way you can get the model number of the furnace it came out of?

Unfortunately, I don't have access to the old furnace information as the blower has been in my shed for a few years now. I am hopeful to learn from @Gutman 's suggestions but please if anyone else has an ELI5 version of instructions, I will take those too.

 

[Innovate1]

The link the cobbler provided has most the details you need. The 5 pin connector is power and a jumper that is installed for 120V operation and left off for 240V input. The 16 pin connector takes 24VAC signals. So you need a 24V transformer to make it stand alone. Inputs on different pins give different speeds. If you have the unit it came out of you should be able to figure out which of the 16 pins is common and which are used for inputs. A little experimentation and you could put a switch for some of the 24V pins as a speed selection.

 

[Innovate1]

If you succeed in getting it running (or find an older type), be sure to devise some type of restriction on the output opening (I use old license plates) and tune it with an amprobe. Those squirrel cage fans need a restrictor or they'll try to move more volume of air than the motor can handle. One of the ones I use will draw 14 amps if unrestricted, after "tuning" (adjusting how much area the plate is covering) it drops to a little over 7 amps and runs much cooler. Keep in mind in normal use, they're pushing a column of air into a duct system..

Many of the ECM motors try to control airflow so when the output is wide open they reduce output and when the outlet is restricted they ramp up speed and power - just the opposite of a blower with an induction motor. Blocking the output when it's running will quickly tell you which gives higher power and best not to run at max power.

 

[Innovate1]

Should be able to find more details on the 16 pin connector signals with some net searching. Here's a couple I quickly found.

https://www.munchsupply.com/media/assets/docs/03860_1119_ECM_Troubleshooting_Tech_Tip.pdf
http://www.descoenergy.com/pdf/pdfnew2/General Electric Variable Speed Troubleshooting Manual.pdf

 

[American Locomotive]

Based on the documents posted, I think this might work:

- Get a 24vac doorbell transformer

- Applying incoming power to the Black and White wires on the 5 pin plug on the motor, green wire to ground

- On the large 16 pin plug: Ignore the orange and purple wires. Tape them up and put them off to the side. Tie the blue and yellow wires together. Get a 24v doorbell or furnace transformer. Connect the blue and yellow wires to one terminal on the transformer and the red wire to the other terminal.

- Power up the motor and doorbell transformer.

 

[tool_scrounge]

Or just put up a wanted ad on Craigslist for an old school used multi speed furnace fan. Or even buy one used on eBay. Furnaces usually get replaced for something other than fan failure. Just hook up 3 wires for AC wall power (ground included) to get the speed you want and you are done.

 

[Gutman]

I found several detailed .pdf troubleshooting manuals online that helped me (not a hvac genius) to figure it out. I'm on my phone, or I'd be more specific, but I found one that specifically detailed the different versions of ecm.

 

[scooterbum46]

The reason I check in on GJ every day.. I'd not kept up on the newer motors (and I just bought a new Carrier system !),
Thanks you to Innovate1 and American Locomotive for the handy information.