The Suburban 233102 replacement blower motor is designed for older Suburban SF-series RV forced-air furnaces that use the long shaft flat configuration. This 12V DC motor features a dual-shaft design – one shaft drives the room air blower wheel that circulates warm air through your RV, while the other shaft drives the combustion air wheel that supplies air to the burner assembly.M.C. Enterprises / NBK
This motor is specifically designed for earlier production SF-35 furnaces manufactured prior to 2001, with serial numbers below 012003642. These older units use a different shaft flat position than newer models, making it critical to verify your shaft configuration before ordering.
Suburban SF-series furnaces use two different motor shaft configurations. Your furnace model number alone is NOT enough to determine the correct motor. You must check the location of the shaft flat (notch) – the flat spot where the blower wheel set screw seats. This motor (233102) is correct if the flat is on the LONG shaft, approximately 3½–4" from the motor face. If the flat is on the SHORT shaft (approximately 2–2¾" from the motor face), you need Suburban 521232 instead. If the wrong motor is installed: The blower wheel will not line up correctly, the set screw will miss the flat, and the blower may rub the housing or sit too shallow. The furnace may physically fit but will not operate correctly.
This motor is also known as NBK Parts 20512. Manufactured by M.C. Enterprises for Suburban RV furnace applications.
This motor fits the following Suburban furnace models (with shaft flat on the LONG shaft):
This motor is designed for older SF-35 furnaces manufactured prior to 2001 with serial numbers below 012003642. Furnaces above this serial number use the newer 521232 motor with a different shaft flat configuration. How to read Suburban serial numbers: Furnaces manufactured after January 1990 have 9-digit serial numbers. The first 2 digits indicate the year of manufacture. The next digits indicate the week of the year. Start with the year to determine whether your serial number is above or below. Example: A serial number beginning with 98 (1998) is a lower serial number than one beginning with 01 (2001).
1. Disconnect power – turn off furnace and disconnect 12V supply 2. Access the motor – remove furnace cover/access panel 3. Mark wire positions – note which wire goes where before disconnecting 4. Check the shaft flat – confirm the flat (notch) is on the LONG shaft before proceeding 5. Remove blower wheels – carefully remove wheels from both shafts (they may be tight) 6. Remove mounting screws – typically 2 screws on short shaft side 7. Install new motor – reinstall in reverse order 8. Align set screw to flat – ensure blower wheel set screw seats firmly on the shaft flat 9. Test operation – verify proper airflow and no unusual noises
The furnace motor is a central component in forced-air RV heating systems. When the thermostat calls for heat, the control board energizes the motor. The dual-shaft design allows one motor to perform two critical functions simultaneously:
The motor RPM and size are matched to the furnace's BTU rating. Using the wrong motor can result in poor heating performance, unsafe operation, or premature failure.
Check the shaft flat (notch) location: Flat on LONG shaft → This motor (233102) ✓ Flat on SHORT shaft → You need Suburban 521232 instead The shaft flat is the flat spot where the blower wheel set screw locks into place. If the flat is on the wrong shaft, the blower wheel cannot be properly secured and the furnace will not operate correctly.
SF = Standard Furnace 35 = BTU rating (×1000) F = Fan-only switch equipped
M.C. Enterprises / NBK Parts