MARS 12781 Run Capacitor

When you're out on a service call and find a compressor or condenser fan motor humming but not turning over, the MARS 12781 Run Capacitor is a reliable OEM equivalent replacement to get the system back online. This 30/5 MFD 440V dual run capacitor is engineered for high-duty HVACR applications, providing the necessary phase shift to support both the compressor and the fan motor from a single, round metal case. With a 370/440 VAC dual voltage rating, this unit offers the flexibility to replace lower voltage capacitors, reducing the need to carry multiple SKUs on your van. It features non-PCB metallized polypropylene film for dielectric stability and a wide operating temperature range of -40°C to 70°C, ensuring it stands up to the thermal stress of a mid-August heatwave. Designed for safety and reliability, it includes an internal physical interrupter and quad-blade terminals for fast, secure wiring. This JARD series component meets UL, CUL, and CSA standards, ensuring it meets the rigorous performance requirements of professional contractors.

Key Benefit List:

• Dual-Section Operation: Provides 30 microfarads for the compressor and 5 microfarads for the fan motor, allowing for streamlined HVAC capacitor replacement.
• High Voltage Versatility: The 440V rating allows for safe installation in both 370V and 440V systems, ensuring superior electrical resilience.
• Durable Construction: Housed in a rugged, rust-resistant aluminum canister designed for high-vibration HVAC environments.
• Safety Certified: Features an integrated pressure interrupter that disconnects the capacitor in the event of an internal failure, preventing casing rupture.
• Precision Tolerance: Maintains a +/- 5% capacitance tolerance for consistent motor torque and improved energy efficiency.

Common Questions:

Can I use a 440V capacitor to replace a 370V unit?
Yes, you can always go up in voltage, but never down. Using this 440V capacitor in a 370V system is a standard industry practice that often leads to a more robust electrical setup.

Does the physical size of the capacitor matter?
While the electrical specs must match, the physical dimensions (2" diameter x 3.625" height) are critical to ensure it fits within the existing mounting strap or bracket in the condenser service panel.

How do I know if the MARS 12781 is failing?
Technicians should look for visible bulging at the top of the canister, oil leaks, or a "hard start" symptom where the compressor struggles to pull full load amps. Always verify the MFD rating with a multimeter during preventative maintenance.

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.