Air Conditioner Troubleshooting: 11 Reasons Why Your AC Is Not Working & How to Fix Them
When the temperature goes beyond 90F, you don’t feel like leaving your perfectly conditioned room. Now, imagine, on an extremely hot day, you turn your AC on, but nothing happens. You press the button again, yet again nothing happens. You want it to be a bad dream and try once more, but unfortunately, it does not start.
It’s time for air conditioner troubleshooting.
To help you out, we have listed 11 reasons why your residential AC might not be working. We’ll cover how you can troubleshoot your AC unit, so you are not left stuck in the middle of summer.
After all, no one wants their air conditioner to stop working in the sweltering heat!
Learn about air conditioner troubleshooting beforehand and be prepared in case you face a breakdown. This guide applies both to central and ductless units such as mini-splits.
1. Thermostat Issues
Thermostat is the part of an air conditioner that regulates your indoor temperature. If your room temperature goes beyond your desired setting, the thermostat will know and turn off your air conditioning and vice versa.
However, sometimes your thermostat may stop functioning. Your room’s temperature may be hotter or cooler than the desired setting. The thermostat may start giving erroneous readings, or in the worst case, stop working altogether. This requires a call to the HVAC technician. They can determine if the thermostat only needs to be recalibrated or a replacement is due.
Whenever you’re doing thermostat troubleshooting, consult the user manuals of your HVAC system. Read it to learn about the recommended settings and the guidelines you need to follow.
Moreover, check the thermostat’s settings for your central air conditioner or the AC mode for any AC. Could you have accidentally set to heat mode instead of cool? Or perhaps your home thermostat is broken.
Smart AC controllers work like thermostats for ductless air conditioners (mini-split, window, and portable units). If you have any of these, check its setting or restart and try reconnecting it again
2. Leaking Ducts
Ductwork can often be the hidden culprit behind your air conditioner’s troubles. According to Energy Star, leaking ducts make up to 20% of the cool air being lost. This makes it very important to take care of your ducts and prevent any leaks.
Hire a professional if you suspect your vents aren’t pushing out enough air. They will perform a detailed checkup of your ducting network and discover any holes or leaks, which can then be repaired. This is most commonly a problem in older structures or where the ductwork has been in place for a long time.
With the cool air escaping through ducts, your room never reaches the lower desired temperature. As a result, your air conditioner keeps on working all the time, which also results in increased AC costs.
Refer to this article to learn about AC duct cleaning and maintenance for additional information.
3. AC Is Not Turning On
This problem mainly signals a power issue more than anything. If you turn on your air conditioner and nothing happens, it is time for air conditioner troubleshooting.
As a first step, check if any indicator lights on your air conditioner are turned on. Next, try disconnecting the power for a minute and turning it back on. If this doesn’t work, you might have to go over the fuses and circuit breakers connected to your unit. It might just be a case of having to reset the tripped circuit breaker or replacing the blown fuse. Otherwise, the problem might lie much deeper in the air conditioner itself, such as loose wiring or thermostat problems.
4. Blower Motor or Fan Issues
This is a problem most often encountered within ducted systems. The blower motor is responsible for routing the cool air through the system of ducts and into your rooms. If it isn’t working at full power, then air might not reach your room at all.
Most commonly, the air conditioner troubleshooting steps involved in this case are straightforward. You just need to clean the layer of dirt and grime on the blower motor fan.
5. Clogged Drainage
An air conditioner cools down your room by removing the moisture. This moisture is collected in the drain pan and flows into a drain pipe. Over time, the drain pipe can become clogged with dirt and mold, restricting the flow of water. This can overflow the drain pan. Mold and algae can then grow where the water has accumulated, and in worst cases, even result in a short circuit. Therefore, it is best to quickly empty the drain pan and keep the drain pipe dry and clear.
6. Frozen Evaporator Coil
If you are turning your air conditioner on and cool air is not coming from the vents, it usually means that the evaporator coils are frozen. This is because the evaporator coils become very cold during the cooling process. If there isn’t enough air flowing over them, they can freeze. This restricts airflow into your room and prevents the room air from getting cool.
Troubleshooting AC unit, in this case, is best done by a qualified professional. They can check the source of blockage for the evaporator fan and check for any refrigerant leaks.
7. Airflow Issues
If your air conditioner is not blowing out any air at all, then this indicates an airflow issue. In the case of mini-splits, the fan on the evaporator coils isn’t running at full efficiency. For a central system, this can be the blower motor.
With the fan not pushing enough air into your room, you can feel your AC is not working efficiently. After some time, this can lead to the evaporator coils freezing. Hence, it is necessary to troubleshoot this AC problem at the earliest.
Dirty air filters also interfere with airflow. If you feel a decrease in the airflow of your AC, check if air filters need cleaning. You should clean them after every 250 hours of usage and replace them after three months.
8. Low Refrigerant Levels
An AC refrigerant is the workhorse behind your air conditioner’s cooling system. If it is in low quantity in the system, your air conditioner will not cool as effectively as it should. The result is warm air coming out of your air conditioning vents.
In such a situation, call your HVAC technician. They will refill the refrigerant to the required levels.
9. Noises Coming From Your AC Unit
An air conditioner has many moving parts. The evaporator and condenser fans, compressor, bearings, fan belts; all are components that can contribute to unwanted noises coming out of your air conditioner.
Troubleshooting ac unit noises involves carefully listening to the noise as the type of noise can identify the type of issue. The most common cause of noise coming from any AC is dirt and dust accumulated in the fan bearings. They interrupt its rotation, making a grinding noise. For the outdoor units, debris can get stuck inside them and interfere with the proper functioning of the fan.
Go over the outdoor unit regularly, and clean the area around it to prevent debris from getting inside. You can even get an air conditioner cover for its protection.
10. AC Smells Bad
There can sometimes be a very peculiar odor coming out from your air conditioner vents. This pungent and humid smell can be very unsettling and ruin your indoor environment. The most common cause of such smell is the growth of mold inside your air conditioner due to improper drainage of water. A damp and cold environment is the perfect breeding ground for mold.
To prevent such a problem, clean your air conditioner thoroughly and then leave it to dry before turning it back on.
11. Faulty Compressor
The compressor is an integral air conditioner component, without which your system wouldn’t work. Therefore, if the compressor isn’t working properly, your unit will not cool as much as it should.
Signs of a faulty compressor are grinding noises coming from AC, excessive vibrations, and frequent tripping of circuit breakers. Moreover, it could cause much greater problems down the line if left unattended. It may even require an air conditioner replacement. Immediately call an HVAC technician for troubleshooting AC unit to avoid any major inconvenience.
DIY Air Conditioner Troubleshooting
Your air conditioner may be faulty because of many reasons, as mentioned above. The first step is to identify the issue that you’re facing with your system. When you know the problem, you need to figure out what part is causing that issue. Figure if it’s the outdoor or the indoor unit or the thermostat.
After you find out the most probable cause, take your tools and start the repairing process. Don’t forget to turn the power off. Then, repair the faulty parts and test your system to see if it worked.
If you don’t see where the problem lies after opening up the unit, leave it there and take professional help. It is best to consider the magnitude of the problem before troubleshooting your AC on your own. For example, if it just needs cleaning the condenser, evaporator coils, and air filters, you should do it yourself. But if the problem is related to a faulty compressor, leaking refrigerant, or any other part that you don’t have enough knowledge of, better contact a professional.
Now that you know how to troubleshoot an air conditioner, you can quickly locate a problem and solve it before it leaves you sweating in the middle of summer, and enjoy a comfortable, cool afternoon!