Lennox 78F90 Motor

The Lennox 78F90, also identified as the Lennox 78F9001, is a heavy-duty Permanent Split Capacitor (PSC) blower motor engineered for reliable operation in furnace and air handler applications. As a 1/2 HP, 1075 RPM unit, this motor is a direct OEM replacement designed specifically for Lennox residential and commercial systems requiring a 208-230V, single-phase power supply. Built on a 48 frame with a 5.63-inch body diameter, the 78F90 features a 1/2-inch x 2.5-inch shaft, providing the mechanical torque necessary to maintain proper static pressure across the evaporator coil. This 3-speed motor utilizes sleeve bearings for smooth, quiet performance during high-cycle demands and is designed for horizontal mounting using a torsion flex bracket.

When replacing a Lennox blower motor, ensuring electrical compatibility is critical. The 78F90 requires a 10 MFD 370 VAC run capacitor (sold separately) to maintain proper phase shift and motor efficiency. Its CCWLE (Counter-Clockwise Lead End) rotation and steel frame construction make it a resilient choice for technicians looking to restore factory-spec airflow. Whether you are performing an HVAC motor replacement or a routine system overhaul, using this OEM Lennox 78F9001 ensures the internal motor windings and thermal protection align with the original equipment manufacturer's control board logic, preventing the nuisances often associated with universal aftermarket alternatives.

• Direct OEM Compatibility: Replaces the Lennox 78F9001 seamlessly without the need for mounting modifications or complex wiring changes.
• Three-Speed Versatility: Offers adjustable airflow regulation for precise heating and cooling performance across different ductwork configurations.
• Industrial-Grade Build: Features a durable steel frame and aluminum flange to provide superior heat dissipation and corrosion resistance.
• Optimized Efficiency: The 1/2 HP 1075 RPM PSC design balances power consumption with high-volume air delivery.

What is the difference between the 78F90 and the 78F9001?
Technicians should note that these part numbers are identical; the 78F9001 is simply the extended factory part number for the standard 78F90 motor.

What capacitor does the 78F90 motor require?
This motor is designed to operate with a 10 MFD / 370V run capacitor. It is standard practice to replace the capacitor during any condenser fan motor or blower motor installation to ensure the longevity of the new unit.

Can this motor be used for both heating and cooling?
Yes, the 3-speed configuration allows the Lennox 78F90 to be wired for different speeds—typically a lower speed for heating to maximize temperature rise and a higher speed for cooling to manage latent heat removal.

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Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.