MARS 12166 Run Capacitor

The MARS 12166 is a professional-grade 70/7.5 MFD 440V dual run capacitor engineered for high-demand HVACR applications. Designed for condensing units and heat pumps, this round dual run capacitor integrates two separate capacitance values into a single oil-filled aluminum canister to support both the hermetic compressor and the condenser fan motor. Built to EIA-456-A standards, it features a pressure-sensitive interrupter that safely disconnects the internal circuit if internal pressure exceeds safe limits, preventing catastrophic shell failure. The MARS 12166 is rated for 440VAC but remains fully backwards compatible with 370V systems. With its non-PCB dielectric oil and 1/4" male quick-connect terminals, it provides a direct OEM replacement for various residential and commercial brands, ensuring PSC motor efficiency and stable phase shift under high-load cycles. This MARS 70/7.5 MFD capacitor is the standard for techs needing a reliable, UL-recognized solution for AC capacitor replacement in the field.

Key Benefits for HVACR Applications

• Dual-Section Logic: Dedicated 70 MFD for the compressor (Herm) and 7.5 MFD for the fan motor, reducing component count in the electrical cabinet.
• Universal Voltage Compatibility: The 440Vac rating provides a safety margin for 370V systems, handling line voltage fluctuations more effectively.
• Safety-First Design: Equipped with an internal physical interrupter to mitigate risks during End-of-Life (EOL) conditions.
• Built for the Field: Features clearly labeled C, FAN, and HERM terminals for foolproof wiring during HVAC motor capacitor swaps.
• Thermal Resilience: Operates efficiently within a broad temperature range of -40°C to +70°C, essential for rooftop and outdoor installations.

Common Questions

Can I use a 440V MARS 12166 to replace a 370V capacitor?
Yes. In HVAC electrical systems, you can always up-rate the voltage. A 440V dual run capacitor will operate safely in a 370V application, provided the 70/7.5 microfarad ratings match the motor requirements.

What is the tolerance of the 70/7.5 MFD rating?
The MARS 12166 is manufactured to a +/- 6% tolerance. When testing with a multimeter, the compressor side should read between 65.8 and 74.2 MFD, while the fan side should read between 7.05 and 7.95 MFD.

Does the physical size of the round canister matter?
Yes. This round dual run capacitor typically measures approximately 2.5 inches in diameter. Always verify that your mounting strap or bracket can accommodate this form factor before installation.

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.