The Dayton 1TDT3 is a direct-drive centrifugal blower motor designed as a drop-in replacement for the Dayton 4C870. Running at 1420 RPM on 230V single-phase power, it moves 559 CFM with a compact footprint suitable for HVAC, ventilation, and equipment-cooling applications. Ball bearings, automatic overload protection, and Class B insulation make this a long-service-life unit built for demanding duty cycles.
When your Dayton 4C870 blower motor fails, the 1TDT3 slots in without modification. Identical mounting flange dimensions (6-5/8 in W x 5-5/8 in H), matching 12 mm shaft diameter, and the same clockwise rotation mean you reconnect the wiring, bolt it up, and get back to work. Also catalogued as NBK Parts number 20518 for cross-reference purposes.
At 559 CFM and 1420 RPM, this motor delivers steady, consistent airflow for forced-air ventilation, fan-coil units, small air handlers, and similar equipment. The 0.97-amp draw at 230V keeps operating costs low while the built-in thermal overload protector guards against burnout during high-ambient or restricted-airflow conditions.
Precision ball bearings on both ends support longer service life and quieter operation compared to sleeve-bearing designs -- suitable for continuous-duty installations.
Built-in automatic thermal overload protector shuts the motor down if it overheats and resets automatically -- protecting the unit without manual intervention.
Class B insulation rating handles continuous operating temperatures up to 130 deg C (266 deg F), well above typical ambient conditions in ventilation applications.
Overall dimensions of 9-1/8 in W x 11-1/8 in H x 10-3/8 in D keep the unit manageable at 6 lbs -- easy to handle during a solo replacement job.
Direct replacement for: Dayton model 4C870. The 1TDT3 matches the flange pattern, shaft size, rotation direction, voltage, and airflow rating of the 4C870 -- no adapters or modifications required.
Also known as: NBK Parts 20518. If you have sourced this unit under the NBK catalogue number, you are ordering the correct motor.
The 1TDT3 uses a squirrel-cage (forward-curved centrifugal) wheel design -- the standard choice for HVAC air handlers, fan-coil units, unit heaters, commercial ventilation cabinets, and equipment enclosure cooling. The 6-1/4 in wheel diameter with a 3-1/8 in width is matched to the 5-1/4 in inlet diameter for efficient static pressure recovery at moderate duct resistance.
Inlet air temperature limit: 104 deg F (40 deg C) maximum. Do not draw air from sources exceeding this temperature. The motor is rated for the air volume and static pressure of the original 4C870 application -- verify your system's static pressure requirements before installing in a new application.
Note: Mounting hardware, blower wheel, and wiring connectors are NOT included. Reuse hardware from the original 4C870 installation or source separately.