DIY Home Improvement Forum banner

1 - 16 of 16 Posts

·
Registered
Joined
·
297 Posts
Discussion Starter #1
Hey Pros, I need some advice.

I have been presented with the following situation and could use your expertise. Homeowner has a brand new Whirlpool 93% gas furnace (Armstrong in disguise). It was started and ran great for a few days. Very quite and went through the traces as usual. A couple days ago he noticed that when not operating, there was a pretty loud humming noise coming from inside. He removed the door and said that there was a loud humming coming from the control board. He went through the steps of touching all the components, blower, draft inducer, etc to see if it was resonating from elsewhere, but it appears to be from the board. He said that it was almost vibrating.

Any thoughts on what this could be? He did not say anything about the 24V transformer. That is my first thought. I am going to steer him to a service call, but I am trying to figure the "why & what" out.

Any help or thoughts appreciated.
 

·
BIGRED
Joined
·
487 Posts
There are small board mounted relays on many circuit boards. One on this board could have a loose winding or a bent relay "frame" inside it's little plastic housing. If this is the case about the only thing you or he can do is replace the board. Those little buggers usually are soldered to the board and hard to get replacements for unless you are the manufacturer.
 

·
Registered
Joined
·
297 Posts
Discussion Starter #3
Hey Bud, where are you in N. IL?
 

·
BIGRED
Joined
·
487 Posts
A place that the map services know as Fox River Valley Gardens. We changed our village name a few years back and now some of the maps actually know us as Port Barrington. Howdy Neighbor
 

·
Administrator
Joined
·
39,661 Posts
The home owner would't be Mr. Jones would it.
 

·
Registered
Joined
·
297 Posts
Discussion Starter #6
The home owner would't be Mr. Jones would it.
Smith maybe :laughing:

No, this is really a homeowner asking me a question. I do not know him and he appears to be about 1,200 miles from me.

I really am just looking for the "what or why" on this. I am minimally technical and am just doing triage before a tech diagnoses.

But I do appreciate your cynicism:wink:
 

·
Banned
Joined
·
5,990 Posts
not in any particular order

Use an empty garden hose with a helper 10' away to isolate the sound.
Put an isolated scope across the fuse so you can monitor current draw and see how much of the total 5A is being used to power this oscillation.
Disconnect downstream devices to break the feedback loop.
Look for a bad ground connection, which will provide feedback from everything to everything else.
Measure the freq. of the vibration.
 

·
Registered
Joined
·
297 Posts
Discussion Starter #8
Use an empty garden hose with a helper 10' away to isolate the sound.
Put an isolated scope across the fuse so you can monitor current draw and see how much of the total 5A is being used to power this oscillation.
Disconnect downstream devices to break the feedback loop.
Look for a bad ground connection, which will provide feedback from everything to everything else.
Measure the freq. of the vibration.

What part of "I am minimally technical" did you not understand:)

I was told, and I left this out that it was a 60 hertz vibration. I do not know how he knew this, but that was in the email. I will pass your comments along. So are you saying that you are suspicious of a bad ground?

Thank you for your input. I really do appreciate it.
 

·
Hvac Pro
Joined
·
22,781 Posts
Most of the time it is the 24 volt transformer buzzing. Not dangerous but annoying. The windings come loose or were never shellacked properly at the factory. There are 6 or less relays on a board and they are all de-energized when the unit is not running so they rarely buzz. Only exception is if the fan is ON. I have never replaced a board for a buzzing relay but I usually do Carrier/Lennox 90% of the time.
 

·
Banned
Joined
·
5,990 Posts
Most of the time it is the 24 volt transformer buzzing. Not dangerous but annoying. The windings come loose or were never shellacked properly at the factory. There are 6 or less relays on a board and they are all de-energized when the unit is not running so they rarely buzz. Only exception is if the fan is ON. I have never replaced a board for a buzzing relay but I usually do Carrier/Lennox 90% of the time.
I can't find it now, but someone had a method for re-shellacking noisy 'formers.
 

·
Registered
Joined
·
297 Posts
Discussion Starter #11
I can't find it now, but someone had a method for re-shellacking noisy 'formers.
That is DIY on steroids:laughing:

Most 24V transformers that I have ever represented have been under $10
 

·
Administrator
Joined
·
39,661 Posts
Smith maybe :laughing:

No, this is really a homeowner asking me a question. I do not know him and he appears to be about 1,200 miles from me.

I really am just looking for the "what or why" on this. I am minimally technical and am just doing triage before a tech diagnoses.

But I do appreciate your cynicism:wink:
Maybe your Mr. Smith, is this Mr. Jones
 

·
Hvac Pro
Joined
·
22,781 Posts
Sounds like 58hz to me.:yes: I'll have to dig out the ole osillyscope to know fer sure.
 

·
Registered
Joined
·
297 Posts
Discussion Starter #16
Maybe your Mr. Smith, is this Mr. Jones

Wow! Small world. I was doing the Easter thing yesterday and never saw this. I guess it is. My bad. I thought you were referring to me as Jones.

Thanks for bringing that to light. I am glad to know that he as heard from this group already. I do not pretend to know these things. I do enjoy helping people find answers.
 
1 - 16 of 16 Posts
Top