Sleepless In Chicago -- Trane System Persistent "Whistle"/"Whine" Noise

[JimDan]

Hi All!

I'm a first-time poster. Actually a friend mentioned that this is the best technical HVAC community on the web, so I was excited to sign up. My problem (one which neither Trane field support nor even Nate-certified techs have been able to resolve, even though I purchased the 10-year extended warranty), is that there is a persistent "whistle" or "whine" noise in higher speed blowing modes. Indeed, they have replaced 5 inducer motors, 2 main blower motors, the main blower squirrel cage and the main blower motor electrical module...yet, the problem has only worsened to the point that it is hard to concentrate on reading, television or particularly sleeping.

Our system is comprised of the following components: A/C Compressor: 4TTX6048B1000A; Furnace: TUY120R9V5W6; CleanEffects: TFD245ALFR000AA; A/C Coil: 4TXCD061AC3HCA; Trane Touchscreen Thermostat: TCONT803AS32DA. Ironically, we replaced a 28-year old Rheem which, though a rust bucket, was extremely quite (just the airflow could be heard). One tech says he thinks it's a secondary heat exchanger problem, while another tech thinks it could be something as simple as a mismanufactured/misaligned part within the furnace assembly.

At this juncture, no one seems to know. I've read much about return ductwork and unsealed cabinetry purportedly causing similar issues. However, one Trane factory field technician and several dealer techs assured me everything was sealed and installed just fine, and that there appears to be no problem with the ductwork system.

I would be indebted for life if anyone can provide any insights or ideas, and would be particularly interested to learn if anyone has encountered this precise type of issue...and, particularly, what you did to resolve it.

Thanks in advance for any assistance you might provide!

All the best,

Jim

P.S. Have digital sound file if anyone wants to hear it (unfortunately, it could not be attached to this post)!

[Old Lennox]

I am just a homeowner but I would be screaming for a new furnace. I would think it certainly would be cheaper for them at this point.

[BaldLoonie]

That's a big furnace, probably undersized ductwork whistling or maybe a register trying to move more air than it is designed to. Whistling is usually air noise, not equipment fault.

[JimDan]

Thanks Old Lennox and Bald Loonie, respectively.

1) At least one dealer tech said the same thing...would have been (and arguably still will be) cheaper for Trane to replace the whole shebang versus continue to try ad hoc fixes.

2) Regarding ductwork, I've heard this said before. However, both the Trane factory rep and the dealer have "certified" my ductwork as being acceptable for this installation. Perchance, is there a way you know to "trace" the point of origin so that I/we could cure the ductwork issue you suggest? It sure sounds (to everyone) that the noise is coming from the furnace cabinet...would that still mean ductwork to you?

Thanks again!!!