Goodman Furnace: No Y or Y1 Terminals? What's 'R' For?

Old 01-15-14, 10:07 PM
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Goodman Furnace: No Y or Y1 Terminals? What's 'R' For?

Just finished installing one of those Evergreen IM 'ECM conversion motors in my furnace (third motor in 8 years...yikes!). All seems well so far; it's at the right speed for heat & it slows to a really nice, super-low constant-speed that'll save a ton of money. I run the fan ALL the time...that kinda plays into the # of motor replacements!!

But I don't know what'll happen when I need AC, as the my furnace board only has W, G and R low-voltage control Y or Y1 (funny, there are spaces for them, and those spaces are both labeled 'Y', but there are no connectors there).

Of course, Y is the call-control for A/C (the high/higher motor speed), so I don't know what to do to get a higher speed for when I use the AC?

Of course, since this is an ECM motor (designed to replace PSC motors), the fact that my old motor had 3 high-voltage connectors going to 3 different speeds on the board (high voltage side) doens't mean anything. The speeds for this motor are ONLY controlled by the low-voltage thermostat connections. W is working the furnace/low-speed, and that's really it, as you leave G unconnected to the motor , as that keeps the low, constant-speed, and I don't know what "R" does, as that's not referenced at all in the Evergreen manual. There are like 3 other low voltage speed-control wires coming off the motor (brown, orange and yellow), but I'm leaving them capped (you CAN connect them to the G connection, but that increases the speed for the fan-only setting, which I don't want to do).

Do I want to use R as a replacement for Y (connect the high-speed motor-control wire to it)...what is R for? Or is this old/cheap furnace not really the best match for this motor, because it lacks low-voltage Y connections? In that case, do I need an external, motor-control unit that I can flip when changing from heat to cool?

I guess I need two levels of expertise here; someone who knows Goodman control boards, and someone who's worked with these Evergreen ECM retrofit motors...hopefully it can be one person!

Thank you!!
Old 01-16-14, 11:58 AM
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Do you currently have AC now? If there's no Y then you just wire the Y from the stat to one side of the condenser contactor and common for the other side. G will be powered on a call for cooling so the fan will come on.

Are you sure the screw just aren't missing from the terminal block?

Also, for the price of all those motors, you could've gotten a nice variable speed condensing furnace
Old 01-16-14, 11:25 PM
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What's the full model number of your furnace?

What happened before when you used a/c? Did the fan jump to high speed? A G call might get it to run on high speed on your furnace. (G gets called for during call for a/c)

Right now can you control continuous fan from the t-stat?

With respect to "ultra-low speed" -> be careful, your furnace needs to move a certain amount of air to work properly. Did you check the temperature rise after changing the motor?

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