My aquastat hums every now and then. I just smack it once and it stops.

 

Transformers can buzz. It is because of the 60Hz current going through them is making the laminationa in the core strike each other because of the magnetic flux. You might be able to isolate the transformer or the box the transformer is in and this might isolate the humming. Rubber padding between the transformer and the furnace might dampen the humming.

 

Yep, 60 hertz hum is a common problem. And a thin piece of rubber often takes care of it.

 

Actually, 60HZ transformers should not hum. They are designed and must meet the standards issued for 60HZ operation. PUTTING VIBRATION ISOLATORS ON THE TRANSFORMER MOUNT ONLY REMOVES THE SYMPTOM...IT DOES NOT ADDRESS THE CAUSE.

Humming is actually a sign of possible problems with either the supply voltage, cycle rate, or even the transformer itself. The voltage being supplied should be checked (+or- 10% of rated primary (supply side) voltage should be present). Make sure the taps are correctly wired for the voltage being utilized on the primary side of the transformer. If the supply side voltage is not correct, this is your problem and your electrician should be able to isolate whether the cause is local or from the utility.

If the primary or supply voltage to the transformer is correct...check the secondary or load side of the transformer. Voltage should be 24 volts...give or take a few percentages. If it is not and the supply or primary voltage checks out replace the transformer.

ALSO....TRANSFORMERS INSTALLED AT THE FACTORY HAVE A VA RATING. MAKE SURE THERE IS NOT MORE LINEAR FEET OF TSTAT WIRE THAN ALLOWED!!! MANY INSTALLERS OVERLOOK THIS. FOR EXAMPLE MANY MANUFACTURERS LIMIT THE AMOUNT OF TSTAT WIRE TO 100FEET. IF YOUR INSTALLER GOES OVER THIS YOU WILL MOST DEFINITELY GET A HUMMM AND POSSIBLE OPERATIONAL PROBLEMS. IF THIS IS THE CASE HAVE YOUR INSTALLERS REPLACE THE FACTORY TRANSFORMER WITH A REPLACEMENT WITH ADEQUATE VA.

 

Actually, 60HZ transformers should not hum. They are designed and must meet the standards issued for 60HZ operation. PUTTING VIBRATION ISOLATORS ON THE TRANSFORMER MOUNT ONLY REMOVES THE SYMPTOM...IT DOES NOT ADDRESS THE CAUSE.

Humming is actually a sign of possible problems with either the supply voltage, cycle rate, or even the transformer itself. The voltage being supplied should be checked (+or- 10% of rated primary (supply side) voltage should be present). Make sure the taps are correctly wired for the voltage being utilized on the primary side of the transformer. If the supply side voltage is not correct, this is your problem and your electrician should be able to isolate whether the cause is local or from the utility.

If the primary or supply voltage to the transformer is correct...check the secondary or load side of the transformer. Voltage should be 24 volts...give or take a few percentages. If it is not and the supply or primary voltage checks out replace the transformer.

ALSO....TRANSFORMERS INSTALLED AT THE FACTORY HAVE A VA RATING. MAKE SURE THERE IS NOT MORE LINEAR FEET OF TSTAT WIRE THAN ALLOWED!!! MANY INSTALLERS OVERLOOK THIS. FOR EXAMPLE MANY MANUFACTURERS LIMIT THE AMOUNT OF TSTAT WIRE TO 100FEET. IF YOUR INSTALLER GOES OVER THIS YOU WILL MOST DEFINITELY GET A HUMMM AND POSSIBLE OPERATIONAL PROBLEMS. IF THIS IS THE CASE HAVE YOUR INSTALLERS REPLACE THE FACTORY TRANSFORMER WITH A REPLACEMENT WITH ADEQUATE VA.

This post has be re-posted b/c one of the above is your problem. Control transformers in HVAC equipment(60HZ) will not hum UNLESS THERE IS A PROBLEM. To those in this forum pay close attention to the trade the posters are part of. In the HVAC forum it makes logical sense to give more consideration to those involved in the trade such as Doc, Flash, Beenthere, and so on. Folks in visiting the HVAC forum are looking for answers not assumptions or guesses.

 

Nothing is perfect. And transformers can hum if the laminations aren't fully glued to each other or the windings aren't tight enough to hold them together. Usually it happens with age, but sometimes right out of the box. I doubt the supply current is wrong if it is hooked in to the same breaker box as everything else.

 

So you are saying HVAC transformers are perfect and cannot hum and cannot be defective? That it always has to be a problem somewhere else? That it is totally out of the realm possibility that it is the transformer and not something else?

I have a gas fired modine heater that the transformer hums on. The T stat wire is about 30' long. As long as it has power to it it hums. Is this a problem?

Cause I have 3 more that do the exact same thing and are set up the same way. So this cannot possibly be the transformer and has to be the way the pro set them up?

 

ouch!

Leo's description of delaminating core is also one that I've come across. I'm not sure if it's 'truly' a problem, I would guess that the efficiency of the step down transformer would be in question, but w/ such small currents needed, may not be an issue. That hum sure is irritating though!

 

5-star shouldn't change anything. He just bought the product, and should he touch anything, it can give the hvac installers an excuse to wash their hands of the situation.

We don't know exactly how things were said betwen 5-star and the installer, but, "it's a supply voltage thing, get the electrician to fix it" is not an acceptable answer. It wouldn't have taken much to simply change the transformer, and see what happens.

Sometimes it baffles me to see how people tend to shift the blame, instead of addressing the issue.

 

5-star shouldn't change anything. He just bought the product, and should he touch anything, it can give the hvac installers an excuse to wash their hands of the situation.

We don't know exactly how things were said betwen 5-star and the installer, but, "it's a supply voltage thing, get the electrician to fix it" is not an acceptable answer. It wouldn't have taken much to simply change the transformer, and see what happens.

Sometimes it baffles me to see how people tend to shift the blame, instead of addressing the issue.

Your absolutely right , thank you , it's really not the electricians problem , I forwarded some of your guys replys , and I appreciate all of your guys responses !

Thanks again

 

I've only come across a humming transformer when there was a problem such as it was going out/weak or where there was a miswiring issue.

No, a transformer should never hum.

 

I took jr high and high school courses in electronics. While I was in High school I had to go to college because they ran out of stuff to teach me. Then I went to college for my electrical engineering degree. So I might know a few things about electronics and transformers.

Plus I use to build electronic things for fun. It's not like it is out of my field.

 

All transformers hum, I buy 12DC and 16/24AC in bulk and I can tell ya every once in a while you will get a real hum-dinger and I just toss it in the bin.

If the hum is loud have the HVAC guy replace the transformer, easy-peasy.

 

Not all transfromers hum. Again, I've only come across it in hvac control transformers when there was a problem. Bigger transformers, yes. More often than not without any problem.

You are talking about magnorestriction, the metal core made up of sheets of metal which extend, expand and contract, and thus chatter against one another when voltage is applied to the metal.

 

In the op's case the transfomer should have been changed, imo.

 

Nice post, as I now know a little bit more about transformers. I dd not know the reason for the humming.

 

I too went to school but only last year. Had no idea myself until then. Luckily my instructor was very well educated and thorough.

As a lead installer for the first decade in this trade I remember thinking I knew it all. School and then service made me realize I knew nothing.

 

I went to school back in '98. The instructor was a little overwhelmed as it was his first year as a teacher. I fondly remember customers asking where I learned how to fix equipment.

My answer was something about the refrigeration program at our local c.c.. Truth of the matter is that although I learned a lot about super heat/ sub-cool and how to read wiring diagrams, and use multi meters at school. A lot my learning came by working at their homes.

I did let the smoke escape out of the motor windings a couple of times.

 

I agree that all of these transformers make some detectable noise or hum. With the smaller ones you may or may not normally be able to hear it over ambient noise without a mechanics stethoscope, but it is there and it’s referred to as fundamental noise. The bottom line though is that most guys can generally tell right off the bat when something just isn’t normal and I believe that most of us would just take care of it instead of trying to shift things on to someone else.
Every now and then you do just get a bad one that won’t quite down. It’s rare, but I’ve even had this happen with 40VA and 60VA Honeywell and TACO plate mounted ones right out of the box before and those are generally very good, quite transformers.

 

Here's a good read.
http://www.federalpacific.com/literature/drytrans/10transformernoise.pdf

 

Well boys I started HVAC school in 1980 and have continued to go to school ever since. I have "let the smoke" out of a lot of parts over the years (LOL thanks flash)

So here is the answer to this post:

Transformers hum. They also get warm. If the noise they make is a problem you can try hitting them this some times stops the hum. I would suggest the handle of a screwdriver works best. A less barbaric and perhaps more reliable method is a rubber slip under the mounting screws.

All this being said the op's installer should simply warranty this one and hope the new one is quiter

 

Well boys I started HVAC school in 1980..

Tell the truth, did you have a mullet? :clap:

 

B,

 

I'll say it one more time, I've only come across a humming low control step down transformer, anywhere from 460 to 24 to 120 to 24 volts transformer, when something was wrong.

Things that cause a humming transformer would be the insulation deteriorating, loose connections or a load issue.

 

Never have I heard a "Healthy" Transformer hum when it was NOT under a load.

 

They all hum. So more than other and some horribly more. It is the nature of the beast.

Put your ear up against it and you can hear it. If it is in a tin enclosure then that can amplify the sound.

A normal transformer should not be heard, but it still hums if you really try to hear it.

 

I agree... But this is NOT the case with the OP. OP is speaking about a Hum that is of concern, between cycles.


Hell... Ever experienced a "Blackout" and wonder WHY it was so serene?

I can hear Ambient Electrical Noise at every waking and alert moment. We all can.

Hell! I used to hear peoples TV sets as I walked past their homes... Back when the CRT's required such Transformers. I could not stand the sound of a TV in the same room... Especially in the seconds between the program and the commercial!

 

That was the refresh rate of the screen that you heard from the transformer and it was much higher in frequency, 60Hz is pretty low as a sinewave but when it is a rattling it is very noisy.

 

It was the guns... Absolutely.

 

Originally Posted by CAS
Actually, 60HZ transformers should not hum. They are designed and must meet the standards issued for 60HZ operation. PUTTING VIBRATION ISOLATORS ON THE TRANSFORMER MOUNT ONLY REMOVES THE SYMPTOM...IT DOES NOT ADDRESS THE CAUSE.

Humming is actually a sign of possible problems with either the supply voltage, cycle rate, or even the transformer itself. The voltage being supplied should be checked (+or- 10% of rated primary (supply side) voltage should be present). Make sure the taps are correctly wired for the voltage being utilized on the primary side of the transformer. If the supply side voltage is not correct, this is your problem and your electrician should be able to isolate whether the cause is local or from the utility.

If the primary or supply voltage to the transformer is correct...check the secondary or load side of the transformer. Voltage should be 24 volts...give or take a few percentages. If it is not and the supply or primary voltage checks out replace the transformer.

ALSO....TRANSFORMERS INSTALLED AT THE FACTORY HAVE A VA RATING. MAKE SURE THERE IS NOT MORE LINEAR FEET OF TSTAT WIRE THAN ALLOWED!!! MANY INSTALLERS OVERLOOK THIS. FOR EXAMPLE MANY MANUFACTURERS LIMIT THE AMOUNT OF TSTAT WIRE TO 100FEET. IF YOUR INSTALLER GOES OVER THIS YOU WILL MOST DEFINITELY GET A HUMMM AND POSSIBLE OPERATIONAL PROBLEMS. IF THIS IS THE CASE HAVE YOUR INSTALLERS REPLACE THE FACTORY TRANSFORMER WITH A REPLACEMENT WITH ADEQUATE VA.

This post has be re-posted b/c one of the above is your problem. Control transformers in HVAC equipment(60HZ) will not hum UNLESS THERE IS A PROBLEM. To those in this forum pay close attention to the trade the posters are part of. In the HVAC forum it makes logical sense to give more consideration to those involved in the trade such as Doc, Flash, Beenthere, and so on. Folks in visiting the HVAC forum are looking for answers not assumptions or guesses.

The above has again been reposted. I hope Five Star has success in eliminating the problem. We have run across this many times, mostly on older equipment, and when we leave the problem is fixed. This is what I and others here do for a living and therefore we speak and give advice from a point of experience. Let us know how it works out Five Star!!

Former posts have been reposted again. In the above the OP will find their answer. Good luck and let us know how it works out Five Star.

 

It’s been a while, but from what I remember of past dealings with PQ issues, simple unbalanced loads generally wouldn’t make transformers buzz any more than usual, just overheat. The harmonics from non-linear loads is what caused them to buzz loudly in addition to overheating, especially when the frequency was at the 3rd harmonic and above.

 

OK: yes I had a mullet it was intense I would still have it but it all feel out

Leo G; you did say it first but I said it beater :whistling:laughing: its just what I do.

I'd rather be an old fart than a dead fart.

 

OK: yes I had a mullet it was intense I would still have it but it all feel out .

:thumbup: