Heat Pumps and Electric Heating - Should fan control make noise?

The fan on my electric furnace has been running continuously. I've been shutting it down at the breaker except when needed. A few times, when turning the power back on, there has been a raspy buzz (60 Hz?) from the unit loud enough to hear all over the basement, but I haven't been able to duplicate it when the panel is off, except that last night it occurred briefly but quit before I could get to the furnace.

After I exercised the limit lever back and forth and turned the limit on the fan control all the way up (it goes to 90), the fan seems to have returned to normal operation. However, the fan control still makes a hum audible even with the panels replaced (but not nearly as loud as the buzz mentioned above.

Should I replace the fan control? It is labeled CamStat F47-TS-3T-90C, or maybe the TS is really T5. The closest thing I've been able to find online is the CamStat F47-3TD-120-25C. Would that work?

Mike

Yes replace the fan control It sounds like the points are burnt. That would be the buzz you hear.

ED;)

Does the part number above seem right? Images in on-line catalogs look like the same shape, and the circuit diagram says "90°" so that's in the right range. Is T3 the designation for the 3 inch probe length?