OEM Lennox Scroll Compressor 20,300 BTUH R-410A — 12U78

The genuine OEM Lennox 12U78 is an Interlink APA020MAA scroll compressor rated at 20,300 BTUH, built for 380V (max), 3-phase, 20–60 Hz, R-410A Lennox equipment. This compressor pressurizes and moves refrigerant through the system to produce cooling, and its scroll mechanism provides smooth, energy-efficient performance with fewer moving parts than reciprocating units.

Common failure symptoms: loss of cooling while the unit still runs, tripped breakers or blown fuses on startup, excessive noise or vibration, overheating and thermal cutout, or a unit that draws high amperage without building pressure. A grounded winding, open circuit, or seized rotor confirms the compressor needs replacement.

Why OEM matters: Lennox specifies exact capacity, voltage, frequency, and oil charge for each application. The factory-matched 12U78 ensures your system reaches rated capacity and efficiency while remaining fully compatible with Lennox controls and R-410A metering. Non-OEM substitutes can cause capacity mismatch, poor oil return, and warranty loss. For a lasting repair, replace the filter drier, verify the charge by subcooling or superheat, and evacuate the system to a deep vacuum before startup.