Lennox 97H74 Run Capacitor

Ensure your service calls are completed efficiently with the genuine Lennox 97H74 Run Capacitor. This heavy-duty 45/10 MFD 440V dual run capacitor is designed specifically for Lennox, Allied, and Armstrong condenser units, providing the exact phase shift required for high-efficiency HVAC compressor and fan motor starts. As an OEM replacement capacitor, it maintains the precise electrical tolerances (+/- 5%) necessary to prevent motor overheating and premature winding failure. The oval dual run capacitor design facilitates superior heat dissipation and fits standard mounting brackets without modification. Rated for 440 VAC applications, this 45+10 microfarad component is backward compatible with 370V systems and features a 10,000 AFC (Available Fault Current) safety rating. Whether you are addressing a humming fan motor or a non-starting compressor, the 97H74 provides the industrial-grade reliability required for both residential and light commercial cooling systems.

• Direct OEM Match: Replaces old part numbers 78H19, 97H7401, and 78H1901 to ensure seamless physical and electrical fit.
• High Dielectric Strength: Rated for 440 Volts AC to handle voltage spikes and harsh summer operating temperatures without degradation.
• Dual-Action Support: Supplies 45 microfarads for the HERM (compressor) circuit and 10 microfarads for the FAN circuit from a single canister.
• Standard Terminology: Features standard 1/4-inch male quick-connect terminals clearly marked for Common (C), Hermetic (HERM), and Fan (FAN) wiring.
• Environmental Safety: Non-PCB oil-filled design meets modern environmental standards while providing internal protection against pressure-related ruptures.

What are the signs that a Lennox 97H74 capacitor needs replacement?
Technicians should look for physical bulging at the top of the canister, oil leakage, or a "humming" sound from the outdoor unit. Using a multimeter, if the capacitance reading drops below 5% of the 45 or 10 MFD rating, immediate replacement is necessary to protect the compressor.

Can I use an oval capacitor to replace a round one?
Yes, provided the MFD and Voltage ratings match exactly. While the internal chemistry is the same, you must ensure the mounting strap is tightened or adjusted to secure the oval form factor of the 97H74.

Is the 97H74 compatible with 370V systems?
Yes. A 440V capacitor is a superior upgrade for a 370V system as it offers a higher insulation threshold, though you must never replace a 440V capacitor with a lower-rated 370V unit.

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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.