The Dayton 1TDU9 is a direct-replacement blower motor engineered for dependable airflow in HVAC, furnace, and ventilation applications. With a compact housing, ball bearing construction, and automatic overload protection, it slots in where the original Dayton 4C940 lived -- no modifications required. Also cross-referenced as NBK Parts 20534.
When your original blower motor wears out, a precise drop-in replacement saves time and eliminates guesswork. The 1TDU9 matches the housing dimensions, shaft diameter, rotation direction, and electrical specs of the Dayton 4C940 exactly, making it a reliable service replacement for furnaces, air handlers, small HVAC units, and similar blower-equipped equipment.
Ball bearing construction extends service life compared to sleeve bearing designs, especially in installations where the motor runs for extended periods or in higher-temperature environments. The 450 deg F maximum inlet temperature rating makes this motor suitable for demanding thermal environments.
Moves 76 cubic feet per minute at rated speed -- adequate for compact furnace and ventilation blower applications requiring consistent, steady airflow.
Runs at 2680 RPM on 50 Hz or 3020 RPM on 60 Hz, making it compatible with both North American 60 Hz and international 50 Hz power systems.
Ball bearings provide longer service life and handle higher operating temperatures better than sleeve bearings, reducing maintenance frequency.
Built-in thermal overload protection shuts the motor down if it overheats, then automatically resets -- protecting the motor and the equipment it serves.
The 1TDU9 is the listed replacement for Dayton model 4C940. Housing dimensions, shaft diameter (8mm), rotation direction (clockwise), and electrical characteristics are matched. Also cross-listed as NBK Parts number 20534.
This motor turns clockwise when viewed from the inlet side. Verify your application requires clockwise rotation before ordering -- installing a motor with the wrong rotation direction will reduce airflow efficiency significantly or push air the wrong direction through the housing.
The motor is rated for both 50 Hz and 60 Hz operation at 115V. On 60 Hz (standard US), the wheel spins at 3020 RPM. On 50 Hz, it runs at 2680 RPM. Amps draw is 0.32A at 50 Hz and 0.30A at 60 Hz.
The shaft diameter is 8mm. If you are reusing the existing blower wheel from the Dayton 4C940, confirm the wheel bore is 8mm. If replacing the wheel at the same time, verify the 2-7/8 inch wheel diameter and 1-7/8 inch wheel width match your housing clearances. The inlet opening is 3-3/8 inches in diameter -- check your duct connection before installation.