Brand: NBK part number: 233101 Furnace Blower Motor is a suburban replacement part for the following furnace models: SF-20 (below S/N 12205202)/ SF-20F (below S/N 012205202)/ SF-25 (below S/N 012106952)/ SF-25F (below S/N 012106952)/ SF-30 (below S/N 012003742)/ SF-30F (below S/N 012003742) Replaces old motor 231706 Suburban furnaces after January 1990, have nine digits. The first 2 digits are year of manufacture. The next digits, indicate the week of the year and the remaining digits are serial numbers. Start with the year to determine whether your serial number is above or below, for example; a serial # beginning with 98 is going to be a lower serial number than one beginning with 01.