Having an AC unit that won’t turn on when your home starts getting hot can be frustrating. This problem can occur for a variety of different reasons, some of which may be things that you can fix on your own. Even if you can’t repair the problem on your own, you may still be able to pinpoint what the issue is, which will make it easier for a technician to quickly repair the problem. If you do ever find that your AC won’t turn on, here are the steps you should take to help troubleshoot the problem.
Make Sure the System Has Power
If your AC won’t start, we would always recommend checking your electrical panel first to make sure the system didn’t trip the circuit breaker. The circuit breaker can easily trip if your home experienced a power surge. AC systems can also sometimes have electrical issues or other problems that cause them to occasionally draw too much power, which overloads the circuit and causes the breaker to trip.
If the breaker is tripped, you should first turn off the AC at your thermostat before resetting the circuit breaker. You can then turn the system back on to see if it works properly. If your AC starts and runs as it should, you usually have nothing to worry about as it is likely that the breaker was tripped due to a power surge. If the breaker trips again after you turn your AC back on, it is important that you don’t keep trying to reset the breaker. An AC that continually trips the circuit breaker is usually a sign of an electrical issue and could create a fire hazard if you keep trying to run the system without having an inspection and professional AC repair.
Replace the Air Filter
After checking that the system has power, you will then want to make sure the AC filter isn’t overly dirty. If the filter is dark-colored or covered in a thick layer of dust and debris, you should replace it before trying to turn the system back on. If the system has a reusable filter, you will want to fully wash and clean it.
A clogged air filter will severely restrict airflow, which forces the blower and the rest of the system to work much harder. This can lead to the blower or the outdoor unit overheating, in which case, the system won’t turn on again until it has had enough time to fully cool down to a safe temperature.
Check Your Thermostat
The reason your AC won’t turn on could also be related to some issue with your thermostat. For instance, the thermostat may simply be old and failing or the wire that runs from the thermostat to the AC control board could be damaged. If your AC won’t start and you hear the thermostat repeatedly make a clicking noise when it signals the system to run, it is usually a good indication that the thermostat is worn out and needs to be replaced.
If the thermostat doesn’t signal the AC to run when the temperature is above whatever you have the thermostat set to, you should try turning the thermostat down by 5 to 10 degrees. If the AC then turns on, it typically means that the thermostat isn’t calibrated correctly or has some issue that is preventing it from accurately reading the air temperature. In this case, you will need to have an AC technician recalibrate, clean or replace the thermostat.
If the AC still doesn’t turn on when you lower the thermostat setting, you should then try to switch the thermostat to heating mode to see if your heating system starts. If your heating runs but your AC doesn’t, you can at least rule out the thermostat as the cause of the problem.
Make Sure the Condensate Drain Pan Isn’t Full
All central ACs have a condensate drain system that captures the water that collects on the evaporator coil and funnels it out of the house or into a floor drain. Over time, the condensate drain system can often become clogged with mold, algae and debris. If the system is clogged, water will start to build up inside the drain pan and could eventually overflow and start leaking out onto the floor. Most newer AC systems have a float switch in the drain pan that is designed to ensure the pan doesn’t overflow. If the water level in the pan rises high enough, the float switch activates and automatically shuts the system down. When this happens, the AC won’t run until the drain pan is emptied and the float switch is reset.
This is something you can check for by opening the access door on your air handler. If there is standing water in the drain pan, it indicates that the condensate drain system is clogged. In this case, you’ll need to have a technician unclog the drain lines and then reset the float switch so your AC will then work again.
Listen for Unusual Noises Coming From the Outdoor AC Unit
This last step will require two people as you’ll need one person to turn the AC on at the thermostat while the other person listens to the outdoor AC unit as it tries to start. The things you’ll want to listen for are clicking or humming noises. If all you hear is a single click, it means that the contactor relay switch is broken and needs to be replaced. This relay switch is what receives the signal from the thermostat when the AC needs to run, and it then passes this signal on to the AC unit.
If you hear the unit make repeated clicking sounds, the problem lies with the AC start capacitor. When an AC unit starts, it requires a huge amount of energy. In most cases, the unit will draw three to five times more power during the moments when it starts than it does when running. The issue is that this is typically more power than the circuit can provide. The start capacitor overcomes this problem by storing a strong charge that it releases to help the AC compressor motor and fan motor to start. A malfunctioning or failed start capacitor will almost always make loud, repeated clicking noises when the AC tries to start. You will also often hear a humming noise coming from the unit, and this sound results from the motors attempting to start without the additional power surge provided by the start capacitor. The good news is that replacing a failed start capacitor is one of the easiest and least expensive of all AC repairs.
If your AC won’t turn on, isn’t cooling effectively or has any other issues, you can count on Dream Team Home Services for help. We repair and service all makes and models of central AC units, and we also work on ductless mini-splits, heat pumps and furnaces. Our team also specializes in HVAC installation as well as a full range of residential electrical and plumbing services. Give us a call today if you need your AC inspected or to schedule any other service in the Media, Havertown and Paoli areas.
