How To Test Home Air Conditioner Capacitor
Capacitors give an extra boost to electrical motors when starting under a load condition.
The capacitor attaches to the motor's electrical circuit through two metal terminals at the top of the cylindrical device.
You can think of the capacitor as a short-term storage battery.
Testing the capacitor for problems is generally done when the motor has difficulty starting.
A good indication of a bad capacitor is when the motors fails to rotate and a humming noise is heard.
The best method for testing a capacitor is by using an ohmmeter.
How to Test Home Air Conditioner Capacitor
Shut off all electrical power to air conditioner circuit
Shut off all electrical power to the air conditioner circuit. Whole house air conditioning systems may have more than a single power source. Make sure all power is switched off. If the system's electrical capacitor is warm or hot to the touch, allow the device to fully cool before testing.
Pull electrical wires from two terminals using needle nose pliers
Pull the electrical wires from the two terminals using the needle nose pliers. Make a note as to which color wire connects to which terminal. Remove the capacitor from its mounted location by removing the metal retaining strap that secures the device to the air conditioner housing. If the capacitor is swelled or leaking oil, there is no need to conduct a further test. The device is bad.
Set capacitor
Set the capacitor, with the terminals facing up, on a flat surface.
Remove all stored power in the device by touching the metal stem of the screwdriver to the two metal terminals.
Make sure to hold the screwdriver by its insulated handle.
Switch the ohmmeter's dial to the position of, Rx1 ohm.
Insert the red lead into ohm, connector and the black lead into com, connector.
Touch the metal ends of the leads together.
The meter should read 0 ohms.
Touch the red lead to one of the terminals and the black lead to the other.
The display should move slowly to the right, 0 ohms, and than back down to the left, infinite ohms.
If the meter display indicator does not move, the capacitor has an internal break.
If the meter moves to 0 ohms and stays in that position, the capacitor has an internal short and is bad.
Switch the ohmmeter's dial to the position of, Rx1 ohm.
Insert the red lead into ohm, connector and the black lead into com, connector.
Touch the metal ends of the leads together.
The meter should read 0 ohms.
Touch the red lead to one of the terminals and the black lead to the other.
The display should move slowly to the right, 0 ohms, and than back down to the left, infinite ohms.
If the meter display indicator does not move, the capacitor has an internal break.
If the meter moves to 0 ohms and stays in that position, the capacitor has an internal short and is bad.