TRANE XR14 CONDENSING UNIT Not Spinning Humming

Dual Run Capacitor (45/5 uF, 440V)

The run capacitor provides the essential phase-shifted current to the fan motor's start winding, creating the rotating magnetic field required for torque. A dielectric breakdown in the 5 microfarad (uF) section of this dual-purpose capacitor prevents the motor from spinning, leaving the stator energized and producing a 60Hz electromagnetic hum. This part is the primary failure point in residential condensing units exhibiting these symptoms.

Condenser Fan Motor

If the capacitor is functional, a hum without rotation typically indicates a mechanical seizure of the motor bearings or an internal short in the motor windings. Over time, the lubricant in the sleeve or ball bearings can dissipate or become contaminated, increasing static friction beyond the motor's starting torque capacity.

SKU: MOT18596

AC Contactor

While less likely to cause a hum without spin, a pitted or partially welded contactor can cause a voltage drop or 'single-legging' effect where the motor receives insufficient power to rotate but enough to energize the windings and create audible vibration.

SKU: CTR02573