You may be low on refrigerant
If you’re noticing your A/C unit cycling on and off, it may be time to check the refrigerant levels. “Low” refrigerant levels can cause a unit to cycle on and off and can cause nothing but warm air to blow out of your vents. Put your hand against a vent and check to see If the air isn’t as cool as it should be. Also check the compressor outside – if you notice ice forming on your outside central air conditioner lines after you’ve run it for a few hours – your A/C system could be leaking refrigerant. Low refrigerant can cause your system to perform poorly – or fail altogether.
Refrigerant levels often drop due to small leaks in your compressor that you can’t see with the naked eye, so don’t try to diagnose the problem yourself; a good HVAC technician will typically check for leaks during an annual tune-up if they see that refrigerant levels are low.
When your central air conditioner is blowing warm air, the first thing you should do is check the thermostat. If it’s set to cool, make sure it’s below the room temperature. If it is, there may be a problem with the air conditioner.
The next step is to check the outdoor unit. Make sure that it’s not covered in debris and that there’s nothing blocking the airflow. If there is, clear it away. Then, try turning the unit off and on again. If that doesn’t work, call a technician.
If there’s no problem with either the thermostat or the outdoor unit, there may be something wrong with the indoor unit. Check to see if the filter is dirty and replace it if necessary. If that doesn’t solve the problem, call a technician.
There are several other reasons why an AC unit might not be blowing cold air. You can check to see if the filter is dirty. Airflow can be blocked if the filter is clogged with dust and other debris, which will prevent the unit from cooling the air. It’s also possible that your ducts are clogged or blocked so you may want to check them out. Also make sure that your thermostat is functioning correctly as thermostats can be faulty and communicate incorrectly with the A/C system.
If your air conditioner is blowing warm air, a refrigerant recharge may be all you need. But if you’ve recharged your system several times in recent years or if other troubleshooting tips don’t fix the problem then you may need to call a professional.