AC not cooling down is one of the unexpected air conditioner problems which can have various reasons. Here we are going to mention 9 main reasons why your AC unit is not cooling. If you have studied the article about "AC parts and components", you can easier follow us in troubleshooting your device.
Dirty air filters a reason for AC not cooling
No matter which model of air conditioner you are using in your house or office, if the AC air filter is clogged with dirt, pet hair, pollen or dust, the outlet air flow is limited and the AC efficiency decreases. So, the AC simply won't cool down. Dirty filter seems to be a simple problem but it can cause more serious problems like thermostat failure or frozen evaporator coils.
Note: clean the AC air filters at least once a month and replace it if necessary, especially if you have a pet or you use your AC unit a lot.
AC not cooling for wrong thermostat settings
This is the simplest reason for AC not cooling. So, check the adjusted temperature of your air conditioner and all its other settings before looking for more serious reasons. If the outlet air flow of the AC is so limited, it might be adjusted on night or silent mode. If so, the AC won't cool down properly.
Note: it's better to adjust your AC thermostat on auto instead of on (It depends on the model).
Dirty outdoor unit, a factor for AC not cooling
As you know, the evaporator inside the indoor unit takes the heat and sends it to the outdoor unit. The condenser in outdoor unit leads out this hot air. So a dirty condenser reduces the AC efficiency and can be a reason for AC not cooling.
In order to solve this problem, just clean the condenser and make enough clearance around the outdoor unit.
Tip: if you noticed that the AC unit is constantly turning on and off and doesn't cool down, the dirty evaporator or condenser can be the culprit.
Refrigerant leaking or its low level can be a reason for AC not cooling
Refrigerant is a chemical that transfers heat from the indoor space to the outdoors. Its low level can cause your AC not to cool down.
Note: before any refrigerant charge, make sure there is not any leaking.
Loose nuts and damaged connectors can cause refrigerant to leak out of the refrigeration cycle. If you feel the AC is not cooling the room, check refrigerant pressure. Hearing hissing or gurgling noise from the circuit or having frozen parts inside the indoor unit, can be signs of refrigerant leaking.
Tip: if the refrigerant pressure is normal, but your AC unit is leaking, it can be because of the condensation process in the unit which we have talked about in the article "8 reasons for AC leaking water".
Wrong installation or choice of the AC unit, a reason for AC not cooling
Proper AC installation and choosing the right AC capacity can significantly affect its efficiency. An air conditioner designed for a small space, can never properly cool down a large room. Moreover, the AC unit should not be installed near heating appliances or the window. The outdoor unit should also be protected against direct sunshine. Indoor and outdoor unit heating because of bad installation place, can make the AC not cool down properly.
Tip: in the article "Installing a split AC system in 7 steps", we have mentioned all necessary points to avoid some problems like AC not cooling down.
Faulty compressor and ac not cooling down
Compressor is the heart of the refrigeration system which flows the refrigerant between evaporator and condenser. So if the compressor is faulty, the refrigeration cycle stops. The only solution is replacing the compressor by a technician.
Tip: the compressor capacitor may be faulty which can be tested and replaced if necessary.
AC not cooling down because of the faulty outdoor unit fan
If the outdoor unit fan doesn't work, the AC won't cool down. Try to reset your air conditioner unit by pressing reset or overload buttons. When the unit is off, manually rotate the fan blades. If it spins freely, the fan motor capacitor may be faulty. Test it and replace if necessary.
You can also test the fan motor using an external source to see if the fan is faulty or the board electric circuit
Frozen evaporator coils a reason for AC not cooling
If the evaporator coils are frozen, the AC unit won't work. Check the refrigerant level and make sure the air filters are clean.
Irregular maintenance, the most important reason for AC not cooling
A regular check up by a technician is necessary to ensure your AC unit is working properly and solve any probable problems as a soon as possible before turning into a serious one.
Note: it is recommended to tune up your AC unit twice a year, in the spring and fall.
AC not cooling down can have other reasons too. We just mentioned 9 of them here. If you need more information about air conditioner units, don't miss AC instructional video in HelloTechnic website. Our experts will teach you everything about AC installation, service, troubleshooting and repair through films and animations.
