Lennox 13W87 Run Capacitor

The Lennox 13W87 Run Capacitor is a high-spec 50/7.5 MFD 440V dual-rated component engineered for demanding condenser applications. As a veteran-preferred Lennox OEM replacement part, this round dual run capacitor provides the critical phase shift required to stabilize compressor start-up and maintain efficient condenser fan motor RPMs. Rated for 440VAC, it is backward compatible with 370V systems, offering superior dielectric strength and thermal resistance in high-ambient environments. With a 50+7.5 microfarad rating and a +/- 5% tolerance, this unit ensures precise electrical timing to prevent motor overheating and winding stress. This HVAC capacitor 50/7.5 is the direct 13W87 replacement for legacy part numbers 13W8701, 50-7.5M370V, and 68J91. Designed for continuous duty, it features standard 1/4-inch male quick-connect terminals for rapid field integration. When diagnosing a humming compressor or a fan motor not spinning, this 10,000 AFC protected unit is the industrial-grade solution to restore 440V system performance and protect expensive system loads from premature failure.

• Dual-Purpose Engineering: Simultaneously supports the compressor (50 MFD) and fan motor (7.5 MFD), reducing the required footprint in the electrical cabinet.
• Voltage Versatility: The 440V rating allows for seamless operation in both 370V and 440V applications, providing a higher safety margin against voltage spikes.
• Direct OEM Compatibility: Verified fit for Lennox, Armstrong, and Ducane equipment, eliminating mounting bracket modifications.
• High Thermal Stability: Constructed with non-PCB oil and a robust aluminum casing to dissipate heat during 24/7 cooling cycles.

How do I know if my 50/7.5 MFD capacitor is failing?
Technicians typically look for physical signs such as a "mushroomed" or bulging top cap. Electrically, if the compressor hums but fails to start, or if the condenser fan blade requires a manual push to begin rotating (the "stick test"), the capacitance has likely dropped below the allowable 5% tolerance.

Can I use the 13W87 to replace a 370V capacitor?
Yes. You can always increase the voltage rating (e.g., from 370V to 440V) as it provides better insulation, provided the microfarad (MFD) ratings match the 50/7.5 specification required by the motor nameplate.

What do the ‘Herm’, ‘Fan’, and ‘C’ markings mean?
These are standard industry labels: ‘Herm’ (Hermetic) connects to the compressor start winding, ‘Fan’ connects to the condenser fan motor, and ‘C’ (Common) is the shared line for the incoming power leg.

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.