Air Handler Hums

[summerperson]

I just had installed a new Trane heat pump system. When the system is not running, the air handler produces a "humming" noise. quite annoying. The installer said he had a few like that, but this can't be right. Does anyone know what it can be and how it can be fixed. Any help would be greatly appreciated. Thanks

[BaldLoonie]

Transformer. Replacing it may get you a quieter one.

[big johnson]

Transformer or poor ground. You can't hear it when system runs because it's masking the noise.

[rundawg]

Not that you wanted this much info, but here is a little transformer lesson:

In a typical power transformer, there are two coils of wires wrapped around pieces of iron. The coils are in close physical contact with each other but are electrically isolated.The pieces of iron are called laminations. The laminations are basically small sheets of steel or iron, stacked one on top of the other. They are used to focus the magnetic field, created by the coils of wire.

Transformers work with AC power. They will not work with DC power (like what comes out of a battery). This is due to the fact that transformers work on magnetic fields and the magnetic fields need to change their polarity (North to South and back again) to make the transformer work properly.

When a transformer hums, it is actually physically vibrating or shaking inside of the chassis.

Because transformers work when the coil magnets switch poles from North to South and back again, 60 times a second, DC forces the input coil to always sit in one direction and this makes the transformer a little crazy so it hums.

The short and simple answer is that transformers hum because of an effect known as 'lamination rattle' caused by DC voltage on the line or poor construction or both. 'Lam' rattle occurs in all transformers to some degree, that degree being related to the quality of the transformer and the quality of the line voltage.

Or an even simpler answer - have them replace the transformer and see if it solves the problem.

[docholiday]

Rundawg, good explanation. I hope alot of techs read that... Understanding how something works is always the first step in troubleshooting. As you know, if you aim at nothing, you'll surely hit it. Thanks again.

[es6678]

This is the only place i could find to type my question, so here it is. I have a 1692sqft mobile home, it came with a split system, before i could sign paperwork someone stole the condensor outside, realtors replaced with a goodman 2.5 ton one. Due to the fact i never felt the old one am unsure if this was right size for my home. anyway my question is my air coming out of the vents feels cold but seems like not blowing much in the every room but my room and my bathroom, does it sound like i would need to replace air handler or get a bigger condensor??????????? trying not to have to replace both but during the summer it never gets colder than 85 with unit going all day, my room stays cool but pretty much only room in house! I am a single mom of two so excuse me if not using right terms.

[bmathews]

This is the only place i could find to type my question, so here it is. I have a 1692sqft mobile home, it came with a split system, before i could sign paperwork someone stole the condensor outside, realtors replaced with a goodman 2.5 ton one. Due to the fact i never felt the old one am unsure if this was right size for my home. anyway my question is my air coming out of the vents feels cold but seems like not blowing much in the every room but my room and my bathroom, does it sound like i would need to replace air handler or get a bigger condensor??????????? trying not to have to replace both but during the summer it never gets colder than 85 with unit going all day, my room stays cool but pretty much only room in house! I am a single mom of two so excuse me if not using right terms.

It's a trailer. They are generally built very cheap. If it is an older one, chances are the ductwork under the trailer is garbage due to critters eating it or falling apart. The evaporator coil could be dirty, the blower weak, condenser probably a little small being that it is a trailer and they generally aren't very energy efficient. I would call somebody out to look at it and evaluate it. It's probably not going to be cheap to fix, so good luck.

[docholiday]

someone needs to balance the duct system. The rest cant be known until then but that will likely solve your issue. You should probably have posted a new thread, rather than jumping on board one that has nothing to do with your symptom. Maybe a moderator can move it.

[tomgeer]

Not that you wanted this much info, but here is a little transformer lesson:

In a typical power transformer, there are two coils of wires wrapped around pieces of iron. The coils are in close physical contact with each other but are electrically isolated.The pieces of iron are called laminations. The laminations are basically small sheets of steel or iron, stacked one on top of the other. They are used to focus the magnetic field, created by the coils of wire.

Transformers work with AC power. They will not work with DC power (like what comes out of a battery). This is due to the fact that transformers work on magnetic fields and the magnetic fields need to change their polarity (North to South and back again) to make the transformer work properly.

When a transformer hums, it is actually physically vibrating or shaking inside of the chassis.

Because transformers work when the coil magnets switch poles from North to South and back again, 60 times a second, DC forces the input coil to always sit in one direction and this makes the transformer a little crazy so it hums.

The short and simple answer is that transformers hum because of an effect known as 'lamination rattle' caused by DC voltage on the line or poor construction or both. 'Lam' rattle occurs in all transformers to some degree, that degree being related to the quality of the transformer and the quality of the line voltage.

Or an even simpler answer - have them replace the transformer and see if it solves the problem.

Bravo:D great lesson, I couldn't have put that any better

[tomgeer]

This is the only place i could find to type my question, so here it is. I have a 1692sqft mobile home, it came with a split system, before i could sign paperwork someone stole the condensor outside, realtors replaced with a goodman 2.5 ton one. Due to the fact i never felt the old one am unsure if this was right size for my home. anyway my question is my air coming out of the vents feels cold but seems like not blowing much in the every room but my room and my bathroom, does it sound like i would need to replace air handler or get a bigger condensor??????????? trying not to have to replace both but during the summer it never gets colder than 85 with unit going all day, my room stays cool but pretty much only room in house! I am a single mom of two so excuse me if not using right terms.

Have a full system diag done, First check your ducts below, are they attached? Second change the filter, third check your evep coil, and forth was the blower replaced when original a/c was installed? Some blowers on old trailer furnaces were sized for heat only, not cooling.

[DanW13]

I would have never guesses at that answer but I definately learned something today. Just for the record I thought when something hummed it meant it was working good, or sometimes too good:D

[Zeiss Nut]

Great explanation.

But want to add something.
The Core of Transformer is made out of stacked laminated iron plate to eliminate "Eddy Current" . Other wise The eddy current would heat up the transformer

eddy current is responsible for "Skin Effect" where the current only flow on the surface of conductor in an AC . The higher the frequency the more pronounce the skin effect.

By making the core into laminated plates, the analogy is more skin surface :) and the eddy current cannot jump over the insulated laminate steel plate.

also called Foucault (read FoCo ) current discover in 1851

http://en.wikipedia.org/wiki/Eddy_current

[gevans]

Very informative. I'm surprised no one suggested rubber mounting the transformer. They do all hum, but the problem comes when the hum is transmitted to the casing, it works as a sounding board and magnifys the sound. Isolate the transformer with soft mounts and that problem will go away.
Don't forget your ground... you should run a separate grounding wire if you use soft mounts, instead of relying on the mounting bolt or screw.

[rundawg]

Tongeer, Docholiday and gevans thanks for the comments. Zeiss Nut, your input about "skin Effect" is duely noted for future reference.

[summerperson]

The contractor has suggested removing the transformer from the air handler and relocating it where it would not be heard. He suggests in the attic or crawl space. The unit makes a lot of noise which is really disruptive within the house. Does anybody see a problem with doing this? It would move the transformer out of the living area and in an area where it would not be heard. Would doing this cause any problems with the operation of the air handler? I thank everyone for their help. I appreciate it.

[tunnel_rat]

That sounds a bit crazy.....I have never seen or heard of such a solution. Replace the Xformer. Or isolate it in the unit.

[billygoat22]

I had a situation like that. The transformer must have created a magnetic filed as well- even not touching metal it caused the cover on elec heater to vibrate and make noise.

I moved it away from the originallocation and it was ok.

Next try would be to move it to the outdoor unit. Soem equipment has the trans. in the od unit anyway.

[meoberry]

Just unbolt transformer and insulate metal box with foam tape.making sure to place transformer on foam tape.

[morzy]

This is the only place i could find to type my question, so here it is. I have a 1692sqft mobile home, it came with a split system, before i could sign paperwork someone stole the condensor outside, realtors replaced with a goodman 2.5 ton one. Due to the fact i never felt the old one am unsure if this was right size for my home. anyway my question is my air coming out of the vents feels cold but seems like not blowing much in the every room but my room and my bathroom, does it sound like i would need to replace air handler or get a bigger condensor??????????? trying not to have to replace both but during the summer it never gets colder than 85 with unit going all day, my room stays cool but pretty much only room in house! I am a single mom of two so excuse me if not using right terms.

Hi dear!
You crossed over heheehhe. Will 1st check the model of your airhandler (nameplate) then determine the size or capacity (BTU/HR or TR). Then you check the Condenser Capacity too. If both are match then your condenser is okay. All you have to do is to clean your system, check the duct leaks, clean your fan blower etc.

Gud luck.

[meoberry]

The mobile home manufactures have for some time have been undersizing A/C units. And the ductwork is one size from one end to another (no reduction in size to increase backpressure). That is why it blows good at the ends and not in the middle. I have always stuck to newer mobile homes to have 600 square foot per ton. Older ones 500 per ton. this has always worked for me in florida. suggest a 3ton.

[summerperson]

another piece of infromation I should had added before. The tech unbolted the transformer from the air handler, and not touching the air handler it still continuted with the very loud hum. any idea what it could be. I don't mind putting the transformer in the attic if it solves the noise problem. I just don't want a different problem by reloacating the transformer. thanks again for the help