# ECM noise - resolved



## rejester (Nov 18, 2016)

Sorry about digging up a very old thread but my new Trane XV80 furnace makes a low whine noise on low speed when it spins up and when it spins down. When the fan kicks into high speed I don't here the hoooooooot/low whine noise. They have already replaced the ECM motor but I'm not sure if they also replaced the motor controller (on the actual motor). 
Did your noise go away when fan was on full speed or only at low speed?


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## kb3ca (Aug 22, 2008)

The noise goes away when it gets up to speed. They have replaced my ecm motor three times and the control board once and the noise is still there. When they replaced the motor they replaced the controller as well. It seems that the whining when ramping up and down is just a characteristic of the motor. Only solution I can come up with would be to replace the ecm motor with a psc motor. That would reduce the efficiency and defeat the reason I went for the XV95.
I have decided to just live with it.


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## kb3ca (Aug 22, 2008)

On the first replacement motor the noise was much reduced but over time it increased and I had them replace it several more times. When I bought my system I also purchased a ten year parts and labor warranty for $500 and I have gotten my moneys worth out of it. If I recall correctly Yuri, on of the posters, said it was a trait of those motors to whine. It only does it when ramping up and down for a short period until it gains some speed. I have been dealing with this issue for six years now and I don't think there is anything that can resolve this other than installing a different type blower motor.
Hope this helps.


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## user_12345a (Nov 23, 2014)

i have only heard one ecm motor - was very, very quiet, very smooth. no motor noise, no vibration, just the sound of air movement.

it's possible that if you have undersized ducts the motor will run at a high rpm to get proper airflow. or that there's a power quality issue.

with everything set up right it should make less noise than a regular motor.


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## supers05 (May 23, 2015)

They can have some unusual harmonics with them that some people have trouble getting used to. 

If you only hear it around the furnace area, sound insulation works well. 

If you hear it in your ductwork, then you'd have to line your ductwork, which usually isn't going to happen. You'll just have to learn to live with it. 

The harder they work, the worse the noise. So try to keep your static pressure down as much as possible. Every manufacturer and model will be different. 

Cheers!


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## kb3ca (Aug 22, 2008)

It makes the same noise with the blower compartment door off. Only whines while speeding up and ramping down for a few seconds. No abnormal sounds when up to speed. Four motors have done the same thing. Gets a little louder as the new motors break in. Not real loud, just annoying.


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## kb3ca (Aug 22, 2008)

Forgot to mention that the blower wheel was also replaced each time. Same results.


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## beenthere (Oct 11, 2008)

Probably a defect in the blower housing.


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## kb3ca (Aug 22, 2008)

The last time at my insistence, which was this September, they replaced the entire blower housing assembly and the control board. They said there were some changes to the board and that might affect the ramping scenario. This did nothing to resolve the whining. In comfort "R" mode when the motor first starts to spin up to 50% there is no noise. After about a minute the blower increases speed to 80% and that's when the noise appears. While running at 80% there no abnormal noise but when the thermostat is satisfied and it starts ramping down to 50% the noise reappears. The motor then continues to run at 50% without any whining until it shuts off. This same scenario has occurred on four blower motors, three blower wheels, one complete blower housing assembly, and one new control board. It occurs with or without the blower door on. I really think it's some characteristic of the motor or the controller that's making the noise and at this point I am just going to live with it unless someone figures it out.


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## beenthere (Oct 11, 2008)

I have worked on countless Trane, Carrier, York, etc, VS ECM blower furnaces and air handlers. That make no noise ramping up or down.


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## rejester (Nov 18, 2016)

beenthere said:


> I have worked on countless Trane, Carrier, York, etc, VS ECM blower furnaces and air handlers. That make no noise ramping up or down.


Yes, this. And why should they make any sound. My furnace should be more quiet than the unit I had 16 years ago, otherwise humans have failed (and yes that's debatable but you get it). That's the point I made to my installer. He also said, ohhh, yeah they make that sound. I have tried the unit with the blower door off, same sound. I have tried the unit without the 4" media filter and the door for it, same sound. I found out the installer only replaced the ECM controller on the motor. It was my original understanding he replaced the motor and the controller since he had said it needed to get programmed so there would be a slight wait. Now he's coming back out soon to replace the motor. 

Oh, yeah, I've also went so far to change the duct harmonics to load some of it with a 1/4" thick white nitrile (I have access to bulk rubber goods, this is food grade so it doesn't stink). No change in sound. I know rubber doesn't absorb sound, a open cell sponge or fiberglass type insulation would but it's the only thing I could try so far. Furthermore, this is at LOW RPM. When it's full-on it's just fine.


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## supers05 (May 23, 2015)

rejester said:


> Yes, this. And why should they make any sound. My furnace should be more quiet than the unit I had 16 years ago, otherwise humans have failed (and yes that's debatable but you get it). That's the point I made to my installer. He also said, ohhh, yeah they make that sound. I have tried the unit with the blower door off, same sound. I have tried the unit without the 4" media filter and the door for it, same sound. I found out the installer only replaced the ECM controller on the motor. It was my original understanding he replaced the motor and the controller since he had said it needed to get programmed so there would be a slight wait. Now he's coming back out soon to replace the motor.
> 
> Oh, yeah, I've also went so far to change the duct harmonics to load some of it with a 1/4" thick white nitrile (I have access to bulk rubber goods, this is food grade so it doesn't stink). No change in sound. I know rubber doesn't absorb sound, a open cell sponge or fiberglass type insulation would but it's the only thing I could try so far. Furthermore, this is at LOW RPM. When it's full-on it's just fine.


It's the electronics, and windings interacting. You can try putting a choke rings on the power supply to the fan motor. (they are cheap iron rings that you buy from any electronics parts store or fleabay) Some how it's just resonating in a way that's causing parts to vibrate and make noise. It's a control/design issue of that particular model. The engineers won't admit to it. I've seen it once in a while. 

There's nothing much more that you can do. 

Cheers!


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## rejester (Nov 18, 2016)

supers05 said:


> It's the electronics, and windings interacting. You can try putting a choke rings on the power supply to the fan motor. (they are cheap iron rings that you buy from any electronics parts store or fleabay) Some how it's just resonating in a way that's causing parts to vibrate and make noise. It's a control/design issue of that particular model. The engineers won't admit to it. I've seen it once in a while.
> 
> There's nothing much more that you can do.
> 
> Cheers!


Coil noise? Interesting proposition. I have some chokes I've ripped off AC line cords I could use. I've had coil noise once before on something unrelated and slathered it with adhesive to stop it from resonating. I suppose this would need to be a high temp adhesive. Unfortunately, that would probably void any warranty. But at any rate, you may be onto something.


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## supers05 (May 23, 2015)

rejester said:


> Coil noise? Interesting proposition. I have some chokes I've ripped off AC line cords I could use. I've had coil noise once before on something unrelated and slathered it with adhesive to stop it from resonating. I suppose this would need to be a high temp adhesive. Unfortunately, that would probably void any warranty. But at any rate, you may be onto something.


Try the power leads to the motor first. That won't void the warranty and won't require the adhesive. (clip on style)

Cheers!


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## rejester (Nov 18, 2016)

So I'm still at this. Like kbc3a, I have now had the motor replaced and the blower wheel replaced. No change in noise. One (me) could argue it's slightly worse. 

The motor already has a large choke on the 120 VAC line feeding it. At first I thought it was a transformer but it only had two wires coming off it. I need to test the choke for impedance and make sure it's not shorted. If it were, the motor would still run fine but may cause the noise issue. Hopefully the choke has it's rating printed on it somewhere or a model number. I'm leaning more towards some weird line harmonics. I see this is more common with VFD motors, not much out there on ECM motors.

I talked with another HVAC guy and he suggested moving the AC line supplying the furnace to the other 120 line (of the 240) in the breaker box to see if that changes any line harmonics. I'm going to do that and also test the choke feeding the motor. At least it's two things I can do relatively easy.


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## rejester (Nov 18, 2016)

rejester said:


> ...suggested moving the AC line supplying the furnace to the other 120 line (of the 240) in the breaker box to see if that changes any line harmonics. I'm going to do that and also test the choke feeding the motor. At least it's two things I can do relatively easy.


I moved the furnace circuit in the breaker panel to the other leg of 120v, no change in ECM noise. The only way I can test the choke is with an ohm meter. I don't have an inductance meter. The resistance seems low considering the wire gauge and number of windings at only 0.3 ohm. The mfg, Basler Electric, has not responded to me as to what it should read.


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## Canuckster (Mar 25, 2021)

I know this is an old thread - but having the same issue with a new Carrier Infinity I just had installed.
The echo through the air return wakes my daughter up at night. The installer says there is nothing wrong and he can't hear it. The noise definitely goes away when I remove the filter - so it's definitely some type of load on the motor. I'm really regretting going with this model vs the two stage.


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## SPS-1 (Oct 21, 2008)

Canuckster said:


> The noise definitely goes away when I remove the filter


Restriction can cause very loud noise. A clogged air filter will do it. I assume you have tried a new, clean air filter? Is the new furnace same size as the old one, or did they upsize the furnace and now you got too many cfm's running through your ducts. 
What MERV rating on the filter ? Maybe step down to a MERV 8 for less restriction.


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## Canuckster (Mar 25, 2021)

SPS-1 said:


> Restriction can cause very loud noise. A clogged air filter will do it. I assume you have tried a new, clean air filter? Is the new furnace same size as the old one, or did they upsize the furnace and now you got too many cfm's running through your ducts.
> What MERV rating on the filter ? Maybe step down to a MERV 8 for less restriction.


Hey thanks for writing back.

I'm in a 2600sq/ft house (not including the basement) and they downsized from an 80k BTU Infinity that came with the house when it was built 10 years ago to the 65kBTU Carrier Infinity 59MN7 per the recommendation of the installer. I've replaced the 5" filter AND even put in a 4" MERV 4 and still the same thing.

It now makes two noises. The first is like a vibrating sound when I leave the blower on to circulate air in the house. This goes away when I remove the filter. The second noise is the harmonic pitch that happens when it goes into the heat cycle. The technician was suggesting putting it in a two stage mode like a performance - but then I'm like "What was the point in buying a higher model"

I'm feeling really disappointed because it's not something you can just return to the store because you're unhappy with it. But I would have expected this to be quieter and smoother - not noisier


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## SPS-1 (Oct 21, 2008)

So you got the modulating furnace ?
I expect there will be a number of DIP switches on the control board that can be used to adjust how it runs. I would have figured that if you were complaining about the sound, the first thing the technician would have done is set it to run on the lowest speed setting for as long as possible. So its loud even when running at lowest speed ?
You can likely download the installation manual and compare the settings to what is possible.


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## Canuckster (Mar 25, 2021)

SPS-1 said:


> So you got the modulating furnace ?
> I expect there will be a number of DIP switches on the control board that can be used to adjust how it runs. I would have figured that if you were complaining about the sound, the first thing the technician would have done is set it to run on the lowest speed setting for as long as possible. So its loud even when running at lowest speed ?
> You can likely download the installation manual and compare the settings to what is possible.


He did two things so far - the first was removed comfort settings and then raised the minimum blower speed when it goes into the heat cycle. Here is a recording of one of the sounds. Excuse the low sound - it's my phone. The first 13 seconds are the sound, and then after that you can hear how it goes away when the filter is removed.
(Sorry the link looks like an ad)






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## FurnaceNoise (May 15, 2021)

Canuckster said:


> He did two things so far - the first was removed comfort settings and then raised the minimum blower speed when it goes into the heat cycle. Here is a recording of one of the sounds. Excuse the low sound - it's my phone. The first 13 seconds are the sound, and then after that you can hear how it goes away when the filter is removed.
> (Sorry the link looks like an ad)
> 
> 
> ...


What was the outcome of your furnace noise problem?

I have a similar size home and furnace. I have an 80k BTU 96% efficiency furnace, 3 Tonne AC condenser, 16x25x1” filter.

I adjusted my dipswitch settings to run the furnace on the lowest CFM settings and this made the noise manageable. But on the AC mode, it’s still loud and I read that you shouldn’t be below 350CFM per Tonne of AC. I also tried lower MERV rated filters (12 and 8) and it did not make a difference.

what size filter are you using by the way?


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