I woke up this morning to a 60 degree house. The thermostat is programmed to drop to 65 overnight and return to 68 by 7am, which it did not.

I first checked to make sure my wife didn't change anything, as she recently changed it to run the fan continuously. Everything checked out at the thermostat.

I went to the furnace and powered it down, then back on. The fan kicked on, pilot never lit and the fan shut down after about 30-45 seconds. After the fan kicked off, I heard a continuous humming noise, not a transformer hum either.

I took the cover off and cycled it again with the same results.

I tracked the humming noise to black wheels (which look similar to a bullseye). I manually moved them by hand and realized they were warm. It also had a mechanical smell.

After manually moving these wheels clockwise and counter-clockwise, I cycled the power again. This time, the fan kicked on for about 30-45 seconds, then shut off. Then the wheels spun for about 3 seconds. Again, not ignition or heat, but still the mechanical smell.

It is currently powered off via the switch on the furnace.

Another item I noticed, and never did before, is that there was a furnace filter on the back of the furnace housing. Was the installer just lazy and did not put sheet metal over the hole, or should this filter be there?

The furnace is a Carrier Model 58STA166-20, Series 100.

I have attached a few photos below.

Thanks for any help. I figured I would ask here before calling my HVAC individual.

I am unsure if the wheels are not spinning and getting mechanical smell because the igniter is not igniting or if that part is not allowing the igniter to ignite.

Cheers,
J

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