AC Running But Not Cooling? Check These 4 Things Before You Call
Before you assume the worst, rule out the simple stuff. Confirm the thermostat is set to cool and the temperature is below the room reading, because a surprising number of service calls end at this step. Next, pull the air filter: a clogged filter chokes airflow and can even freeze the coil.
Then check the outdoor unit. If the fan is not spinning, look for a tripped breaker before anything else. Finally, look at the larger copper line at the outdoor unit; heavy frost or ice means the system is likely low on refrigerant or has restricted airflow, and running it further can damage the compressor.
If the filter is clean, the breaker is on, and the unit still blows warm, the remaining causes, refrigerant leaks, a failing capacitor, or a compressor issue, need a licensed technician with gauges. Shut the system off at the thermostat to prevent damage while you wait for the appointment.