Run Start Capacitor, Round, 15/5 MFD, 440/370

Mars 12818 – Dual Motor Run Capacitor for HVAC Motor Circuitry

The Mars 12818 is a dual-value run capacitor designed to support permanent split capacitor (PSC) motor systems requiring two independent capacitance ratings within a single enclosure. Rated at 15/5 microfarads (MFD) and 440V AC, this unit is used in condenser fan and compressor circuits where stable, continuous-phase support is required.

Its aluminum round-case housing, compact profile, and terminal configuration make it compatible with a variety of HVAC units requiring dual motor operation from a shared capacitor assembly. Ideal for retrofit service, scheduled maintenance, and OEM-equivalent replacements.

Component Characteristics

• ✅ Dual Capacitance Configuration – Provides 15 MFD and 5 MFD ratings for simultaneous operation of two motor windings.
• ✅ 440V AC Voltage Rating – Supports systems operating under elevated voltage or frequent cycling loads.
• ✅ Hermetically Sealed – Dielectric protected from moisture and contamination to maintain performance over time.
• ✅ Aluminum Round Case – Optimized for durability and heat resistance under mechanical and thermal stress.

Technical Specifications

• Model: Mars 12818
• Capacitance: 15/5 MFD
• Voltage Rating: 440V AC
• Shape: Round
• Application: Dual motor run capacitor for HVAC systems using PSC motors

Installation and Safety Considerations

This capacitor should only be installed by licensed HVAC professionals. Confirm all specifications—voltage, capacitance, and terminal orientation—prior to installation. Disconnect all power to the system, discharge any existing capacitors, and use proper PPE throughout the service procedure.

• ???? Hand tools for panel access and mounting
• ???? Multimeter with capacitance and continuity settings
• ???? Safety gloves, eye protection, and compliance with LOTO procedures

Capacitor leads must be secured using the proper connectors, and mounting must eliminate vibration or movement that may degrade terminal integrity over time.

Field Use and Application Notes

The Mars 12818 is specified for use in residential and light commercial HVAC equipment requiring a compact dual-run capacitor. It is frequently used in systems where the fan and compressor motors share a common start/run component, reducing the overall parts count while maintaining independent capacitance control. Ideal for packaged rooftop units, condensing units, and air handlers configured with PSC motors.

Operational Advantages

• ✅ Stable Electrical Output – Maintains accurate phase angle to motor windings under continuous duty.
• ✅ High Compatibility – Rated for HVAC systems operating in the 440V class, suitable for OEM-grade performance.
• ✅ Service-Ready Design – Simplifies replacement and installation in both confined and open equipment layouts.
• ✅ Reliability in Demanding Conditions – Designed for extended duty in high-cycle environments.

Professional HVAC Component Summary

The Mars 12818 dual motor run capacitor provides the consistent electrical characteristics needed to support efficient, long-life operation of HVAC motor systems. Its dual capacitance values, high voltage rating, and robust enclosure make it a dependable choice for service technicians and installers requiring precise component replacement across a wide range of equipment platforms.