MARS 12731 Run Capacitor

The MARS 12731 is a professional-grade 35/4 Microfarad 370Vac Round Dual Run Capacitor designed for continuous-duty HVACR applications. This dual motor run capacitor provides the necessary phase-shift and starting torque for both the compressor and the condenser fan motor, ensuring the system operates within OEM peak efficiency. Engineered as a high-reliability 35+4 MFD 370V HVAC capacitor, this unit features a durable aluminum case and a non-PCB, oil-filled interior to maximize heat dissipation and component longevity under high ambient temperatures. With a 370V rating, the MARS 12731 is a standard replacement run capacitor for a wide variety of residential and light commercial air conditioning units and heat pumps. Its compact round form factor allows for universal mounting in standard brackets, while the quad-blade quick-connect terminals simplify wiring during field replacements. This round dual run capacitor meets rigorous industry safety standards, including internal pressure interrupter protection to prevent housing rupture in the event of an internal failure.

• Dual-Section Design: Simultaneously supports the compressor (35 MFD) and fan motor (4 MFD) from a single 370Vac capacitor housing.
• Universal Compatibility: Standard round dual run capacitor dimensions ensure a fit in most condenser electrical cabinets without modifying brackets.
• Field Reliability: High-tolerance microfarad rating ensures consistent motor torque and reduced amperage draw for cooler motor operation.
• Safety Certified: Includes a physical internal interrupter and is UL/CSA listed for secure integration into modern HVAC equipment.
• Durable Construction: Built with an aluminum casing to resist corrosion in harsh outdoor environments.

Can I use a 440V capacitor to replace this 370V model?
Yes, you can always use a capacitor with a higher voltage rating (like 440V) as a replacement, provided the capacitance (35/4 MFD) and physical dimensions match. You cannot, however, use a lower voltage rating than what the manufacturer specifies.

What are the signs that a 35/4 MFD capacitor has failed?
Technicians typically identify a failed MARS 12731 by a bulging top, visible oil leaks, or an out-of-tolerance microfarad reading. Symptomatically, the compressor or fan may hum but fail to start, often leading to a tripped circuit breaker.

Does it matter which terminal I connect the wires to?
Yes. Dual run capacitors have three sets of terminals: 'C' for Common, 'HERM' for the compressor, and 'FAN' for the condenser fan motor. Reversing these can lead to motor failure or poor system performance.

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.