OEM Lennox Potential Relay — 45A00

The genuine OEM Lennox 45A00 potential relay controls the start capacitor in your compressor's starting circuit. As the compressor motor comes up to speed, the back-EMF it generates trips this relay to disconnect the start capacitor, leaving the run capacitor to carry the motor. It is a small but critical component that protects your compressor from the high current draw of a hard start.

Common failure symptoms: a compressor that hums but won't start, frequent tripping of the start capacitor, buzzing or chattering from the relay, or a compressor that trips the breaker on startup. Burnt or welded relay contacts are a common cause of no-start conditions and can quickly damage a start capacitor if left unaddressed.

Why OEM matters: potential relays are matched to a specific pickup and dropout voltage for the compressor they serve. Installing the correct Lennox 45A00 ensures the start capacitor drops out at the right moment, protecting both the capacitor and the compressor windings. Generic substitutes with the wrong voltage ratings can leave the start capacitor energized too long, leading to premature compressor failure. Choose the factory-specified part for reliable starts and full equipment life.