Run Capacitor
Dual and single run capacitors on compressors and fan motors.
AC Breaker Keeps Tripping: How to Find Out Why
How to diagnose an air conditioner or heat pump that keeps tripping its breaker: a grounded compressor, a locked rotor, a shorted fan motor, wiring faults, high head pressure or a weak breaker.
How to Test a Blower Motor: PSC, Constant-Torque ECM and Variable-Speed ECM
How to tell which kind of blower motor you have and test it the right way, from capacitor and amp checks on PSC motors to control signals on constant-torque and variable-speed ECMs.
Replacing a Run Capacitor or Contactor: How to Pick the Right Part
How to choose a replacement run capacitor (µF, voltage, dual vs. single, size) and contactor (coil voltage, poles, amp rating), with the common mistakes that bring callbacks.
AC Compressor Not Starting: Humming, Clicking or Nothing at All
Diagnose a compressor that won't start by what it does: humming points to capacitor or locked rotor, clicking to overload, silence to the control circuit.
AC Not Cooling? A Step-by-Step Diagnostic Checklist for Techs
Work an AC no-cool call in the right order, from the thermostat call to airflow, electrical and refrigerant charge, without guessing.
Condenser Fan Not Spinning: Capacitor, Motor or Control?
Find out why an outdoor condenser fan won't run, from the fan capacitor and seized bearings to the contactor, wiring and heat pump defrost.
How to Test a Run Capacitor: Meter Method and Under-Load Method
Test HVAC run capacitors two ways, with the meter's capacitance setting and under load with amps × 2652 ÷ volts, and know when to replace one.