Tempstar High Efficiency furnace had a hum/buzz typical of a motor trying to start: With the panel removed, and depressing the cut-out switch the fan motor (or something on the electronic panel attached to it) made this sound. The thermostat was set to OFF (set to engage neither furnace nor A/C), and the fan setting on the thermostat at Auto. I didn't think the fan would be trying to start under this scenario.

When I changed the fan setting at thermostat to ON the fan would spin - after a brief delay (3-4 seconds) but with the same noise.

The house is vacant, gas turned off, and only the AC has been used in the last several months.

The fan is dirty - lots of vibration when it did run (7 years old).

The prospective buyer is having a tech in tomorrow, but in the meantime, I'm curious. Any ideas?

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Sounds like a transformer, not the motor.

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Jim Luttrall
Mr. Inspector.net, Inc.
Allen, Texas 75002

Transformer. I just minimized the buzzing on my rental property furnace, and it was doing exactly the same thing. I loosened the screws a little bit and isolated the transformer from the metal bracket with a piece of paper. I can still hear it, but it's much quieter.

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Jim Robinson
New Mexico, USA

Furnace motor buzz?

Good Lord, these kids will try anything nowadays for that buzz.

We used to slam a few beers for a buzz, but I get thats not exciting anymore.

Jim & Jim are correct, it has a 40 VA transformer making the noise. They do this all the time. It's in the way it is mounted. I have seen people hang them so they don't touch anything. Poor way of doing it. All transformers buzz.

Dan