My furnace (Ducane cmpe05ou3) started to make loud noises. When I inspected the propeller of the inducer motor, is was cracked.

The motor is a Fasco No 702111361, P/N 20538701, 115V, 60Hz, 1.9A, RPM 3400, Type U21B, Class B, TP, Sealed Ball Brg.

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I was unable to find an exact match for this kit. My closest matches are these below, just the amp is 1.8 instead of 1.9 and the wiring is slightly different:

My questions are:

  • The models above do not have the exterior temp sensor, but the specs state that they have thermal protection. Is it ok to use them?
  • In the case of the A204, it has the fitting for the thermal sensor, but the wiring toes not seem to use it. Should I try to re-use the previous termal switch?
  • If these are not a good fit, Is it possible to extract the propeller and put in my brokne blower?
  • The furnace is 21yo, the technician told me I needed a new one and that the repair would be CAD$1200. The parts above are about 200-500. Is it worth to fix it myself (I do have electronic skills, but I have little knowledge to judge when a furnace needs replacement). Other than that, the furnace seems to be running well.
  • 3
    21 years I would not be too concerned about 0.1 difference in amps(more efficient motor). The fit is usually more important(bolt hole spacing, not something to duct tape together). Type and maybe class should cover fit.
    – crip659
    Nov 27, 2022 at 20:23
  • @crip659 Yes, is my same opinion. 0.1A may be just efficiency improvement. Other than that, the fit seems to be the same. At least for the A204 and 80M52, two (random) websites claim that they are compatible with my model.
    – Adriel Jr
    Nov 27, 2022 at 20:36

1 Answer 1


I'm a big believer and succeed-er in doing this type of work-around and I would go with the A204, definitely due to the thermal sensor mounting. McCombs and Walmart had the best completion of the missing information that you'll need to confirm...assembly measuring 7-5/8" x 1-1/4" see: https://mccombssupply.com/a204-fasco-inducer-furnace-blower-motor-for-lennox-7021-11406-83l4101-7021-11406/ OR https://www.walmart.com/ip/A204-Fasco-Inducer-Motor-for-Lennox-7021-11406-83L4101-7021-11406/182088626

Though, see if you can find a part# for the propeller if that would fix the sound. Places like Repair Clinic and again Walmart have those too from $13 or $30 or more. See: https://www.repairclinic.com/Shop-For-Parts/a36c9/Furnace-Blower-Wheel-Fan-Blade-Parts OR https://www.walmart.com/search?q=Inducer+Motor+fan+blade+blower+wheel

  • Thank you for your answer. I went with a used RFB547 which I found on eBay (CAD$130) and had fast delivery time. I am considering replacing just the propeller, however, my motor may also be bad, so maybe I'll replace both. If that does not work, I'm planing to find a way to attach the sensor to the "new" kit. I would not look as professional though. I did not know that I could buy just the propeller... it is good to know!
    – Adriel Jr
    Nov 29, 2022 at 19:01

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