Start capacitors can be found in air conditioners, refrigerators, and even in washers. One of the most commonly asked questions is how to test the capacitor on an air conditioner if it starts humming and does not start. A capacitor can actually help you see whether the appliance is working correctly or not. All you will need is a multimeter, and you should be able to check whether the capacitor is working fine or needs a replacement. So if you’re curious how to test the capacitor on an air conditioner, keep reading and follow the step-by-step guide below.
Discharge the capacitor
The first thing that you will have to do is locate the capacitor inside the air conditioner. Capacitors will be metal tubes. They store an electric charge, and you should be able to find it near a motor inside the air conditioner. If you have a screwdriver, use it to open the air conditioner.
After that, locate the capacitor. It’s recommended to use a needle-nose plier, which has an insulated handle so that you can remove wires. Ensure that you have unplugged the air conditioner before locating the capacitor inside it.
Now take the screwdriver that has an insulated handle. If you don’t have one, it’s recommended to buy one; you will find it easily in a hardware store. You should use a screwdriver with an insulated handle because the rubber will not allow electricity to travel through the metal. This way, you will be saved from getting electrocuted. Ensure that you’re taking extreme caution while working with electricity since electricity shock can cause severe damage to your body and health. Along with it, make sure that the handle doesn’t have any crack; if it does, replace it right away.
For added protection, it’s recommended to wear a pair of gloves. Hold the screwdriver’s handle correctly, and then place the shaft of the screwdriver on the positive terminal. You will see a plus sign on the correct terminal. Ensure that you don’t end up touching the other terminal.
While maintaining contact with the screwdriver on the positive terminal, tap on the negative terminal once. Once you make the connection, don’t feel alarmed when you hear a small pop sound. This means that the capacitor is discharging. After the first spark, allow the screwdriver to contact the terminal for some time while tapping on the negative side one or two times. This should be done because sometimes excess charges sometimes are left behind.
Using a Multimeter
Multimeters are good equipment to use to read the capacities and voltage of a battery or circuit. Before using a multimeter, ensure that the capacitor is completely discharged. Digital multimeters are readily available in both online and hardware stores. Take the red probe and place it on the positive terminal. Now use the black probe and put it on the negative terminal. If you’re worried about residual charge, wear a pair of gloves.
Once you do the above, you will see the number fluctuating for a few seconds. You will have to wait for some time to see the readout to have the same number. Disconnect the probes only after seeing the exact readout, and then write down the capacitance numbers. If you fail to see the number moving at all, this is a clear sign that the capacitor needs to be replaced and it has worn out.
The number that you should see should match the capacitor’s number. Look at the capacitor — both the maximum and minimum numbers will be listed on it. In case you end up seeing the capacitance number go up infinitely, then this means that the capacitor needs to be replaced.
These are the two ways to test the capacitor on and air conditioner. If you’re not sure how to calculate it on its own or if you’d prefer some assistance, ensure to call an HVAC professional to do it for you.