MARS 12966 Run Capacitor

The MARS 12966 is a heavy-duty 25/5 MFD 370V oval dual run capacitor engineered for high-demand HVACR applications. Designed to support both the compressor and the condenser fan motor, this dual-section component ensures optimal phase shift for efficient motor startup and continuous operation. Its aluminum case construction provides superior heat dissipation, making it a reliable choice for residential and light commercial A/C unit repair where high ambient temperatures are a factor.

As a veteran's choice for HVAC capacitor replacement, the 12966 features a pressure sensitive interrupter (PSI) that safely disconnects the capacitor in the event of internal pressure buildup. This MARS 370VAC capacitor is physically more compact than round alternatives, fitting into tight control boxes without compromising performance. With a tolerance of +/- 6% and a wide operating temperature range of -40°C to 70°C, it meets the rigorous standards required for modern condenser motor and compressor circuits.

• Dual capacitance (25+5 microfarads) allows a single component to service both the compressor and fan, simplifying inventory.
• Oval-shaped aluminum housing provides a compact footprint for streamlined installation in restricted electrical compartments.
• Built-in safety interrupter prevents case rupture by disconnecting the circuit during end-of-life failure modes.
• Non-PCB oil-filled design ensures environmentally responsible heat transfer and dielectric strength.
• 1/4-inch male quick-connect terminals featured on the herm, fan, and common posts for fast, secure wiring.

• Can I use a 440V capacitor to replace this 370V model? Yes, you can always go up in voltage rating (e.g., using a 440V for a 370V application), but you must never go lower than the original equipment specification.
• Will this fit my specific condenser unit? This is an oval-style capacitor; verify your mounting strap dimensions, as this may require a different bracket than standard round capacitors.
• Why is my compressor humming but not starting? A failing 25/5 MFD capacitor is the primary culprit; testing the microfarads with a multimeter at the "Herm" and "C" terminals will confirm if the part has drifted out of tolerance.

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.