A central air conditioning unit that cycles on and off too quickly is said to be rapid cycling. The rapid cycling can be due to a variety of problems but often can be traced back to a few checks that aren't difficult, but also aren't the first place a homeowner might think to look. Problems in these air conditioner parts can all cause the conditions for rapid cycling.
What are the three places you should check if your central air conditioner won't turn or stay on?
The compressor takes the signal from the thermostat and then outputs a gas refrigerant to start the cooling cycle. If the compressor stops working properly, the important refrigerant fuel won't go into the system at high enough quantities and the cooling process will essentially stop in its tracks.
If you own a multi-meter with a continuity setting, you can test the compressor. Turn off all power to the condensing unit, remove the unit's cover, and then remove the terminal cover on the compressor. Inside, you will find three terminals. Attach your two multi-meter probes to each pair of these terminals to test for continuity, which will make your meter beep. If any of the terminal combos don't beep, you likely need a new compressor.
If the compressor continuity test passes but you don't think the compressor is working properly, the problem could be in the capacitors, which are tiny parts that store electricity to provide boosts for the system. The start capacitor provides its boost at the onset of the cooling, which is when the compressor comes into play. There's also a run capacitor that helps ensure the system has a steady electrical current during operation.
You can test the capacitors with a multi-meter set to ohms setting. Make sure you turn off all power to the unit and then drain the stored energy out of the capacitors. Use an insulated screwdriver to drain the run capacitor. Use your multi-meter set to AC to drain the start capacitor.
Turn the meter back to ohms and then hook the probes up to one capacitor at a time. Make sure the reading matches the number printed on the side of the capacitor. If the numbers don't match, you likely need a new capacitor.
The door switch is a sensor on the blower fan door that stops the fan from working when the door is open. Without the fan, the cold air for your home has no way of circulating and the system can eventually overheat, so the air conditioner will shut down immediately or quickly as a safety measure.
You can test to see if the door switch is the problem by simply opening the access panel on your air handler while the unit is turned on at the thermostat. If the fan isn't blowing and the door inside the panel is open, then you need a new door switch. If the door looks securely closed and the fan isn't blowing, you might need a new fan motor.
Both the door switch and the fan motor can be installed by an air conditioning repair company. Contact a company like CNR Air Conditioning Inc to learn more.