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Discussion Starter · #1 ·
I have a 4 ton heatpump. Single phase, 220v. I'm going to straight duct it into a main living area. Unrestricted return and supply, save for a filter and a few bends in some flex from the unit.

Should I expect that the ECM motor (GE brand) will burn up without any restriction to air flow on the supply side? Wouldn't it simply adjust to it's designed air flow based on how hard it's working?

This question comes from having bought a used unit and when powered and the call for the fan in any mode was made, the inside fan just blew at hurricane force speeds all the time. I was new to this unit and this kind of HP unit in general. I thought this to be normal. After about a week of use and maybe 5 to 6 hours of logged use (via one of those really neat thermostats) and normal run times in heat mode of about 20 to 30 minutes, the inside fan just quit. It was hard to turn and no longer worked.

The fan motor was replaced under warranty with the advisement that because I wasn't running any restrictions to the air flow, the motor would burn itself up to supply the designed level of "WORK" or air flow. I got the fan motor installed and powered the unit up. It's not working like anything the old motor did so far. It's varying it's speed based on the mode the unit is in. For example, if just the fan is called for, it's a gentle breeze and slower speeds. If the unit's heat or cool is called for, the fan ramps up it's speed considerably compared to just the fan mode. It's characteristics are much different than the one that quite working.

I wondered if perhaps the motor before it actually had an issue and burnt itself up because it wasn't throttling itself down. I want to run this unit as cheaply (in terms of ducting) as possible. I also won't be getting another chance at another motor if this one stops too.

Any ideas, advisement's, comments? Thanks.

S.
 

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It needs some sort of resistance on either the return or supply. The air filter can be used to create that resistance.
 

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Discussion Starter · #4 ·
Beenthere,

Now that I'm out of work for the day and off that little phone, thanks for taking the time to respond. I think I bought someone else's problem honestly. For what I"m trying to do, I gotta wonder how long the newer motor is going to last on this thing. I was able to finally go back, use the right search strings, and find people commenting on the ECM motor thing. It really sounds like a nightmare. I guess what I'll end up doing if this motor kicks the bucket is just grab a standard induction motor and make sure it can provide the standard CFM this unit was designed to deliver. If I cover the max, I should at least keep the compressor happy on either heating and cooling mode. I'm not entirely positive at this point if the guy gave me an motor rated at the same H/P than what came off originally. I really can't go back to him though. Not after the reception I got last time. But again, thanks.
 

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straight ducting a 4 ton unit into a living area sounds crazy. How many sq ft is the living area? Hopefully at least 2,000 sq ft.:)
I have never been one for bells and whistles on anything, whether it be vehicles, appliances, or hvac equipment.
I have on my house and have installed many bare bones basic Goodman units and they have been as dependable as the sun.
I'm not a fan of the ecm motor and although people in some parts of the country may benefit from them for humidity removal, etc, they dont serve much purpose where I live and the good ol psc motor lives on tried true and dirt cheap to replace.
 

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It is not that easy or possible to swap an ecm motor with a psc as the wiring from the circuit board has 16 pins for an ecm and a psc uses 2-3 and different relay setup. A psc still needs ductwork to suck against or it will not get up to speed either. has to do with the curve and design of the fan wheel.
 

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It is not that easy or possible to swap an ecm motor with a psc as the wiring from the circuit board has 16 pins for an ecm and a psc uses 2-3 and different relay setup. A psc still needs ductwork to suck against or it will not get up to speed either. has to do with the curve and design of the fan wheel.
Yep, too much free air can burn out a PSC motor far quicker then a VS ECM.
 

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not like the good ole days with a belt drive. :no: the young guys should carefully look at the spacing and curve and pitch of a wheel in a belt drive fan and then a direct drive to notice the difference. I have not seen a brand where you can swap an ecm with a psc but apparently york or goodman? has a terminal on the board for that?
 

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Discussion Starter · #9 ·
Sammy37,
Admit tingly, Nothing I had plans for was really what a typical setup would look like. The space I had it handling was far less than 2,000 sqf, as well. But I had done it with a 3 ton package AC unit with no issues for years. I don't do things the easy way so comfort levels were maintained with a little more work on my part and supplemented with a few window shakers once the temp got to the point I wanted it. The fan the guy replaced the bad motor with a 1/2 HP when the one that came out of the unit was 1 HP. I asked if he would consider taking it back and he did. Though he'll never do business with me again. I guess I'll be rethinking my approach when I regroup and am ready to find another used unit. I do know I do not want a unit with such a finicky type motor ever again. With the way I do things, I can't have something that's so highly intolerant of poor duct planning. Thanks though.
 

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Discussion Starter · #10 ·
Yuri, Thanks man.
Yea, turns out I was able to return the unit. But if looks could kill I would be near dead now. He did just give me a fan from some other assembly to throw in there. If I had read this before I did all this, I would feel even less anxious about all this. I'm feeling certain I would of had more expensive issues just a short time into the summer season.
 
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