# ECM Diagnostics



## DuMass (Feb 6, 2008)

This month’s RSES SAM supplement got me looking around at other diagnostic tools available for the current crop of ECM’s. 
I already have the newer version of the TecMate Pro for Genteq’s 2.0, 2.3 and 3.0 motors which seems adequate if you also couple it with a few other basic VOM readings, but I was just looking over a more expensive tester from Zebra that appears to have more advanced test functions even above that of the old discontinued 4-button TecMate XL.
Since you’re not really testing individual speed windings like on a PSC, the go-no-go test the TecMate performs seems like it should be adequate. Technically, the TecMate is brand specific, but at this point, it seems they are the only ECM’s I can recall seeing anyway.
I do see the advantage of the Zebra VZ-7 in not having to remove the control module to directly test the motor windings, but do you find that all the other test functions the Zebra performs are necessary or of any real value?

Zebra VZ-7: http://getzebra.com/proddetail.asp?prod=VZ-7


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## flashheatingand (May 3, 2008)

Why are we making things so difficult? Joe Homeowner may be impressed with the savings on their electric bill, but when things go bad, they are understandably upset when they get a bill for $750 to get the heat or a/c going. I am not a big fan of ECM's I really believe it is a disservice to install them in most households.


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## DuMass (Feb 6, 2008)

Sometimes you don’t have a choice if it’s already there. I figure if somebody was willing to pay for a premium high efficiency system, then it should be restored to that condition, if possible. This assumes that it was properly installed and set up in the first place. Of course, usually repairing a problem and finding the cause are two different, yet interconnected things. I suppose swapping an ECM out with a PSC would be an option, depending on the system.
As I understand it though, improper air flow because of high ESP due to undersized duct work or an overly restrictive filter seems to be one of the major factors in ECM control module failure. Depending on the circumstances, that may not be something that can be rectified in a regular service call. 
The way I see it, ECM’s are established and the way energy costs are going, they are probably only going to multiply in numbers, so we need the equipment to be able to troubleshoot them efficiently.


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## flashheatingand (May 3, 2008)

Yeah, I hear you. The next question is why making a setup so specialized? We have to buy the gear, and the customer has to pay the price. While walking the dogs, the thought occurred, most of us are resisting, and not buying the stuff. Those first to buy the equipment duct blaster, ecm test kits,...etc are the ones who will benefit the most. 

It may be unfair, but it is what it is. I get the spirit of the movement, it's just the way things are being implemented. By the way, as the attics are more "tight" are you guys experiencing more problems with snow accumulation on the roofs? Or, are the drifts about the same as always?


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## beenthere (Mar 5, 2009)

The majority of all VS ECM failures is from outside influence. So its the installer that creates the large repair bill, not the technology. Next, most VS ECM's are condemned when the motor is fine, its just the module that needs replaced(and it died from a bad install).

Years ago, I was sent to replace a VS ECM under warranty. When i got there, after i removed the blower panel. I found a wire was off at the ignition module. I put the wire back on, and the motor worked. I didn't replace the motor. And its still working today. The customer gets a high repair bill from techs not knowing how to diagnose the problem.

More and more new units are coming through with X13 motors, and in a few more years, you will have a hard time finding a new unit that uses a PSC motor.

I have looked at Zebra's, but haven't bought one yet. Might have to in a little while.


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## DuMass (Feb 6, 2008)

flashheatingand said:


> By the way, as the attics are more "tight" are you guys experiencing more problems with snow accumulation on the roofs? Or, are the drifts about the same as always?


Not me personally, but in other parts of the state there have been like 150 roof and building collapses due to the weight from the record amounts of snow and a seemingly endless barrage of blizzard like storms, along with the sustained freezing temps. Hopefully, winter is ready to pack up and leave.


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## DuMass (Feb 6, 2008)

beenthere said:


> The majority of all VS ECM failures is from outside influence. So its the installer that creates the large repair bill, not the technology. Next, most VS ECM's are condemned when the motor is fine, its just the module that needs replaced(and it died from a bad install).
> 
> Years ago, I was sent to replace a VS ECM under warranty. When i got there, after i removed the blower panel. I found a wire was off at the ignition module. I put the wire back on, and the motor worked. I didn't replace the motor. And its still working today. The customer gets a high repair bill from techs not knowing how to diagnose the problem.
> 
> ...


I’m a bit curious as to what exactly makes ECM’s so expensive. Seems the basic brushless DC motor technology has been around for 40-years and the circuit boards inside the control modules look like something any first year electronics student could build with off the shelf parts.
Other than maybe the rare earth magnets, I’m not sure the manufacturing processes and materials are that much more expensive or elaborate than those used in more traditional motors. 
I also don’t see why the bloated cost of the ECM motor itself should justify the equally inflated cost of replacement control modules.
It just seems that obsene prices are systemic when you mention ECM’S. I see that Zebra sells a replacement 1-ohm-30A thermistor for the GE/Gentec control module boards for $29.00, which can be had retail from most electronics supply houses for about $2.50. I guess maybe if every single component is equally marked up more than 10 times its cost, like that thermistor is, then that could possibly explain things.


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## beenthere (Mar 5, 2009)

Probably so expensive because they knew they would get so many motors/modules back as defective under warranty, that aren't defective or bad.

If for every 100 furnaces that you install. You had to replace 40 of them for free(and you ain't getting the replacements for free). How much more would you have to charge per install to make money and still stay in business.


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## DuMass (Feb 6, 2008)

I suppose that would have to play into it. I’m not sure where to pin responsibility for that sorry 40% return number though.
It looks like Regal Beloit has some decent training info available at no cost and offers a reasonably priced basic diagnostic tool for several of their ECM’s. They still even have the older GE training videos available online that go step by step through their ECM service guide. It seems like a tech that really wanted to learn could do so at his leisure with no out of pocket expense. 
On the other hand, it looks like Emerson only offers closed training classes and the OEM equipment manufacturers are pretty much the same, from what I can tell, so I think these types of barriers may have a part in gumming up the flow of information.


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## flashheatingand (May 3, 2008)

My problem with ecm's is that the homeowner bears the burden. If Ms. Jones wants a system that is quiet, and plans to run the fan 24/7...etc fine, I am glad there is a product out there that will meet her needs. But, the product was put out there with no formal training for techs. If the companies start to phase out the psc's, well, that's wrong and manipulative.


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## beenthere (Mar 5, 2009)

flashheatingand said:


> My problem with ecm's is that the homeowner bears the burden. If Ms. Jones wants a system that is quiet, and plans to run the fan 24/7...etc fine, I am glad there is a product out there that will meet her needs. But, the product was put out there with no formal training for techs. If the companies start to phase out the psc's, well, that's wrong and manipulative.


Lots of formal training has been available since the first VS ECM's and ICM's came out. Its the techs and companies that didn't take advantage of the training that are at fault. Carrier, one of the first to use them. Had training available as far back as 96 that I know of. Probably even before that(and those were the really expensive motors back then).

If a company is too cheap to send their techs to training, that isn't something the manufacturer's can control.


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## flashheatingand (May 3, 2008)

First of all, good post Dumass. I think it will have brought to light what exactly the VS motors are. No matter what the opinion on them, as hvac pros, we can't have the Bambi eyes when encountering one. I cleaned out a v.s. Goodman today, (removed the motor and cleaned the housing), took apart the ec module...etc. 

Three wires on motor plug are black, red, and blue. Is the black hot line1, red hot line2, and blue neutral (motor is 120/220v)? I see it's an a/c motor, so if you can hardwire it, at least for testing purposes, would that work?

Where does the cm get it's signal, the control board? Either way, I'll bet that board aint cheap either. Aye Yay Yay.


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## flashheatingand (May 3, 2008)

beenthere said:


> Lots of formal training has been available since the first VS ECM's and ICM's came out. Its the techs and companies that didn't take advantage of the training that are at fault. Carrier, one of the first to use them. Had training available as far back as 96 that I know of. Probably even before that(and those were the really expensive motors back then).
> 
> If a company is too cheap to send their techs to training, that isn't something the manufacturer's can control.


I have to say, out here, there has been nothing distributed with our supply houses. No excuses, heck maybe I am not pretty enough to be asked to the dance.... . If there has been such a high rate of misdiagnosis, something has to be done. At this point, the manufacturers ought to have more classes on their vs. If that's too spendy, at least they can have an on-line class. Somebody has to step forward. 

I think we will disagree on the v.s. versus psc thing for awhile. But, gotta be knowledgeable.


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## flashheatingand (May 3, 2008)

DuMass said:


> This month’s RSES SAM supplement got me looking around at other diagnostic tools available for the current crop of ECM’s.
> I already have the newer version of the TecMate Pro for Genteq’s 2.0, 2.3 and 3.0 motors which seems adequate if you also couple it with a few other basic VOM readings, but I was just looking over a more expensive tester from Zebra that appears to have more advanced test functions even above that of the old discontinued 4-button TecMate XL.
> Since you’re not really testing individual speed windings like on a PSC, the go-no-go test the TecMate performs seems like it should be adequate. Technically, the TecMate is brand specific, but at this point, it seems they are the only ECM’s I can recall seeing anyway.
> I do see the advantage of the Zebra VZ-7 in not having to remove the control module to directly test the motor windings, but do you find that all the other test functions the Zebra performs are necessary or of any real value?
> ...


I looked at the section for the 16 pin connector. The less expensive one wasn't compatible with 16 pin. And the more expensive one was. But couldn't be used for infinity. 

The Goodmans have a 16 pin connector, and I believe the Tranes do also.


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## beenthere (Mar 5, 2009)

Its not an AC motor, its a DC motor.

Could be the distributors you deal what, are not doing their part in providing training opportunities.

More good compressors are returned as bad/defective ones then VS motors. I believe its in excess of 60%. I seen more then one "tech" condemn a compressor when it was,just that the condenser coil was dirty.


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## flashheatingand (May 3, 2008)

The name plate on the motor said a/c. There was I believe a DC transformer that went to the module. I am under the impression that the DC is used in the module, as there were several capacitors, and that is where the changes happen.


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## flashheatingand (May 3, 2008)

Our distributors may not be doing their part, but, this has to be a collective effort. I know there are plenty of techs who wouldn't mind taking the time to attend a seminar. Did you say 60% error rate? Wow!!! and Nobody has done anything? 

Our supply guys are nice guys. We all have our shortcomings, but, that's another topic.


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## beenthere (Mar 5, 2009)

flashheatingand said:


> Did you say 60% error rate? Wow!!! and Nobody has done anything?


Of course someone has done something. Copeland, Bristol, etc, simply charge that much more for the compressor. So we pay more for condensers/ heat pumps, and replacement compressors then what would be needed. A compressor we pay 250 for. Really would only need to be sold to use for maybe 160, but they got to make up for all of those ones returned under warranty that are good.


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## DuMass (Feb 6, 2008)

flashheatingand said:


> First of all, good post Dumass. I think it will have brought to light what exactly the VS motors are. No matter what the opinion on them, as hvac pros, we can't have the Bambi eyes when encountering one. I cleaned out a v.s. Goodman today, (removed the motor and cleaned the housing), took apart the ec module...etc.
> 
> Three wires on motor plug are black, red, and blue. Is the black hot line1, red hot line2, and blue neutral (motor is 120/220v)? I see it's an a/c motor, so if you can hardwire it, at least for testing purposes, would that work?
> 
> Where does the cm get it's signal, the control board? Either way, I'll bet that board aint cheap either. Aye Yay Yay.


Actually, if it’s GE it is technically a 3-phase DC motor, so the output side of the module is DC. GE says that two of the wires power the motor while one wire carries back EMF to the module so that the controller always knows what position the rotor is in.
They warn that if you ever have to remove a control module, you should wait 5-minutes after disconnecting power to allow those 3 caps to discharge. They supposedly pack quite a wallop and can knock you for a loop.
Yes, the controller is programmed by the equipment manufacturer and gets it signal from the equipment control board. That's why you have to order replacement modules direct from the OEM.

Did you get your copy of RSES mag this month? It has a great SAM supplement in it with a lot of good ECM info.

Check out the videos on GE ECM’s in the link below. There’s lot of good info there. You can also download a copy of their ECM service guide to keep in the truck.

http://www.thedealertoolbox.com/CommercialHVAC/Training/Videos/ECMServiceGuideTraining.aspx


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## DuMass (Feb 6, 2008)

flashheatingand said:


> I looked at the section for the 16 pin connector. The less expensive one wasn't compatible with 16 pin. And the more expensive one was. But couldn't be used for infinity.
> 
> The Goodmans have a 16 pin connector, and I believe the Tranes do also.


I'm not sure, but as I recall, the VS 2.0, 2.3 and 2.5 series use a 16-pin communication connector and the 3.0 uses a 4-pin communication connector. I think they all use a 5-pin connector for line voltage. The X13 uses a single block connector for all the line voltage and communication wiring.


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## beenthere (Mar 5, 2009)

The newest Infinty uses a version 3.0 motor(for about a year now). It will be a while before testers are available from anyone for them. I think only Carrier/Bryant uses that motor at the moment.


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## DuMass (Feb 6, 2008)

beenthere said:


> The newest Infinty uses a version 3.0 motor(for about a year now). It will be a while before testers are available from anyone for them. I think only Carrier/Bryant uses that motor at the moment.


The TecMate supposedly works on the VS 3.0. If you have an older version of the tester, you have to use their 4-pin to 16-pin adapter with it. With the newer version, the adapter is piggybacked directly to the TecMate’s 16-pin connector, so is now essentially all one cord.


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## DuMass (Feb 6, 2008)

beenthere said:


> More and more new units are coming through with X13 motors, and in a few more years, you will have a hard time finding a new unit that uses a PSC motor.


I think it's inevitable given the direction things are heading. I don’t feel that it is necessarily a bad thing though, especially if the equipment manufacturers could somehow manage to come up with a programming standard so that universal replacement control modules could be stocked and standardized test equipment and procedures could be used. This is probably a major reason why these ECM’s are so expensive and possibly the biggest stumbling block preventing more complete industry wide acceptance of them.

It looks like the ECM retrofit replacements for PSC blower motors have been out for a while. I haven’t priced them, but I can only imagine it could be a hard up-sell to make if they are priced anything like other ECM's. If they can get the cost down on them though, I could see these flying off the shelves as utility rates continue to rise.


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## flashheatingand (May 3, 2008)

beenthere said:


> Its not an AC motor, its a DC motor.
> 
> Could be the distributors you deal what, are not doing their part in providing training opportunities.
> 
> More good compressors are returned as bad/defective ones then VS motors. I believe its in excess of 60%. I seen more then one "tech" condemn a compressor when it was,just that the condenser coil was dirty.


Perhaps there are faults with our local distributors, but it's not like one supply house is that different than the next one. I doubt Boise is the only jurisdiction that has this scenario.

Hey, the lack of training is a problem, but you know how S__T rolls down hill? In this case, I think it's coming from above. It seems as though the manufacturers are not "replenishing the earth with nutrients." Take, Take, Take. 

And we complain about the kids today?


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## beenthere (Mar 5, 2009)

The parts manufacturers all have their own classes/courses on their products. From TXV makers to the motor manufacturers. You can find training on them. Yes, you will have to travel if your areas distributors don't provide training.


Here, we have one distributor that even set up a class room in their building, and sponsors regular training courses.


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## DuMass (Feb 6, 2008)

Does Emerson manufacture its own ECM’s or are they just rebranded Genteq? 
They seem to have the same wiring configuration and the specs sound a lot like the Gentec VS, X13, 142r, and Evergreen motors.

http://www.emersonclimate.com/en-US.../Documents/2010EM-2 Variable Speed Motors.pdf


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## beenthere (Mar 5, 2009)

As far as I know, they make their own. The GE has been out long enough now, that the patent for an ECM design doesn't prevent using the same control methods.


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## DuMass (Feb 6, 2008)

beenthere said:


> As far as I know, they make their own. The GE has been out long enough now, that the patent for an ECM design doesn't prevent using the same control methods.


If that’s the case, then it’s probably good that they are so similar. It should make troubleshooting them more consistent. I guess the only other potential odd ball setup might be on the remote mounted ECM draft inducers.


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## beenthere (Mar 5, 2009)

DuMass said:


> If that’s the case, then it’s probably good that they are so similar. It should make troubleshooting them more consistent. I guess the only other potential odd ball setup might be on the remote mounted ECM draft inducers.


Like Trane's BS ECM set up on older units.


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## beenthere (Mar 5, 2009)

DuMass said:


> If that’s the case, then it’s probably good that they are so similar. It should make troubleshooting them more consistent. I guess the only other potential odd ball setup might be on the remote mounted ECM draft inducers.



Yep, still gonna be some of them.


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## BadgerBoilerMN (Sep 10, 2010)

You are all smart guys and we all know _that,_ is not the standard. Smart guys have to know. Sadsacks change parts.

As to the cost of the parts, have you had you truck worked on lately, tried to learn how to diagnose the problem, got factory training on line?

Information is a two edged sword. If you can get training, parts, equipment on line, so can your customer and your competitor. Training costs money and parts are seemingly cheap by comparison (especially if covered under warranty). Factory training is usually the best and why the franchises are so popular and seem to do so well.

If Joe Homeowner wants a pro he will have to pay for it, and if he doesn't, he will pay more for what it gets. In the end we all have to charge enough to maintain our efforts, which includes parts, tools and training. Smart customers appreciate it, the rest call our competitors who drive up the cost of everything.

We got a little snow up here. My kitchen was falling into my basement, but better now with couple new microlams.


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## DuMass (Feb 6, 2008)

beenthere said:


> Like Trane's BS ECM set up on older units.


It’s funny you mentioned that because I noticed that when you try and order a replacement ECM inducer motor, it looks like it cross references to a whole new Fasco retrofit unit complete with a new furnace control board, wiring harness and the works. 
I’m not sure, but it looks like they may have originally been using the GE 44 frame motor [ECM 44] for their ECM draft inducer.

I haven’t seen them yet, but apparently GE/Genteq even has a little 84mm ECM [ECM 84] motor for use in dampers, so looks like these things are really going to be everywhere.


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## beenthere (Mar 5, 2009)

Yep, and we either keep up, or eat dust.


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