MARS 12999 Run Capacitor

The MARS 12999 Run Capacitor is a high-performance 12.5 MFD 370V round run capacitor designed for continuous duty in residential and light commercial HVACR systems. Built to meet UL 810 safety standards, this motor run capacitor features a non-PCB, oil-filled design that ensures effective heat dissipation and internal pressure protection. As a veteran technician knows, the 12.5 microfarad rating is critical for maintaining the proper phase angle in PSC (Permanent Split Capacitor) motors, directly impacting the efficiency of blower motors and small condenser fans. The 370 VAC rating provides a professional-grade insulation margin for standard 240V circuits, while the 50/60 Hz compatibility makes it a versatile HVAC replacement part. This round run capacitor utilizes metallized polypropylene film technology to minimize capacitance drift and prevent premature motor failure. Its compact 1.75-inch diameter allows for seamless integration into standard mounting brackets, ensuring a secure fit during service calls.

• Precise 12.5 MFD Rating: Ensures optimal motor torque and efficiency by maintaining the correct electrical phase shift.
• Physical Interrupter Safety: Features an internal safety switch designed to disconnect the capacitor in the event of an internal pressure buildup.
• High-Grade Metallized Film: Built with self-healing polypropylene film to provide stable performance across a wide temperature range.
• Universal 1/4-inch Terminals: Equipped with standard quad-blade quick-connect terminals for fast and reliable field wiring.
• Rugged Aluminum Construction: The round, seamless can design offers superior durability and heat transfer compared to low-tier alternatives.

Can I use a 440V capacitor to replace this 370V model?
Yes. In HVACR applications, you can always upgrade to a higher voltage rating (e.g., replacing 370V with 440V) as it provides a higher insulation ceiling, often resulting in cooler operation. However, you must never down-rate the voltage.

Will this capacitor work if my motor asks for 12.5 uF?
Yes. Microfarads (MFD) and uF refer to the same unit of capacitance. It is vital that this 12.5 MFD rating matches your motor's nameplate exactly to avoid overheating the windings.

Does it matter which wire goes to which terminal on a single-run capacitor?
For a single-section run capacitor like the MARS 12999, there is no polarity. However, it is professional practice to stay consistent with your common and start leg wiring for future troubleshooting.

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.