Using an ECM motor out of a furnace

[jaddenney]

Has anyone came upon a way to "convert" an ECM motor to make it just have a speed or two or three? I have a furnace blower with an ECM that I want to use as the old style to convert into a shop fan like the old ones used to be able to do with different speed taps. I'd even be happy if I could find a way to make it just turn on to full speed without being in a furnace and lining up with the heating sequence.

[dieseldude]

Google search ways to test speeds on your ecm type, then make it permanent.

[TechmanTerry]

Does this ECM require "back EMF" in order to work properly? The back emf works w/ the duct work restriction?

[beenthere]

Do you mean an ECM, or a VS ECM.

[jaddenney]

Do you mean an ECM, or a VS ECM.

Honestly, not 100% sure. A friend is giving it to me as they are replacing their furnace with an upgraded one and he told me "it's one of those funky ones with a lot of wires going to it", so I'm assuming its a VS ECM, but can't confirm till I get it later in the week. Just getting ahead of the ball to have ideas for when I get my hands on it.
Thanks

[JayMan7]

There is probably a way to run it in full speed. There was a thread on this a while back where I posted a picture of the test tool that powers ecms at full speed... Tecmate pro

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[heatingman]

I believe the test mode does a part speed


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[heatingman]

Has anyone came upon a way to "convert" an ECM motor to make it just have a speed or two or three? I have a furnace blower with an ECM that I want to use as the old style to convert into a shop fan like the old ones used to be able to do with different speed taps. I'd even be happy if I could find a way to make it just turn on to full speed without being in a furnace and lining up with the heating sequence.

It depends on the type of ECM.

If its a constant torque type, then you can just trigger which speed you want.

If true VS - probably not worth the trouble. Ive tinkered with a 2.0 maybe 3.0 I forget which- to very limited success. Essentially not worth it.

If it has a 16 pin connector, then you can via the low voltage terminals run fixed speeds.


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[CircusEnvy]

I snagged an ECM out of a salvaged air handler and put it in my own. Make sure it’s out of a comparable unit to the one you’re installing it in so the blower performance chart can match up close. With a furnace, you might need a relay or two to kick the blower on with heat, but it’s definitely doable.