[josemalone]

I have a Trane XL80 furnace that buzzes. It works fine, just has a constant hum that recently has gotten louder. I can't find the posts I read before, but one mentioned there was a converter (or transformer) and the plates on it have loosened up, hence the humming. Also said this part wasn't serviceable and needed full replacement. Whatever it’s called it is directly behind the control board on the other side of the sheet metal wall. I can see the wires go down and up behind the sheet metal. But I have no idea what that part is called. And looking at part lists, nothing obvious pops out to me. Any help is much obliged.

 

[hvactech126]

transformer

TRR01729

 

[Chimmy]

Transformer wires on the 24v side are RED 24 hot leg into tstat

and the other is Common 4v neutral this is the side of 24v power every low voltage circuit terminates upon to complete its path.
Might I add if you dont know this you are far safer paying someone to fix it.





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[josemalone]

$25 and 15 minutes later - No buzzing!

Thank you again, for your help.

Once I figured out only two screws and some tabs were holding the motherboard and transformer in place it was a fairly quick, and easy swap out. Took a few extra minutes to blow out the dust on the various fans.

Is there anything else I can do to help keep this puppy in working order? I looked around and it seems everything is meant to be swapped out, but not really maintained, such as the furnace in our last house. I had to replace belts and add oil every so often. That thing was a beast!

 

[rootboy]

Or it could be a relay. A relay with a bit of dirt between its iron poles will hum, sometimes very loudly. Turn the unit off and blow out the control box with a can of compressed air and see if that fixes it.