Capacitor Safety Warning
Capacitors store electrical energy and can shock you even when power is off. Always discharge capacitors before testing.
Types of HVAC Capacitors
- Run capacitor: Keeps motor running efficiently
- Start capacitor: Provides extra torque for startup
- Dual capacitor: Combines compressor and fan capacitors
Testing Procedure
- Turn off power to the unit
- Discharge the capacitor safely
- Set multimeter to capacitance mode
- Connect leads to capacitor terminals
- Compare reading to rated value on capacitor
Interpreting Results
- Within 5% of rating: Capacitor is good
- More than 5% low: Capacitor is weak
- No reading: Capacitor is dead