1. Check the circuit breaker. Ensure the circuit breaker controlling the central AC unit is turned on. If the circuit breaker has tripped, reset it.
2. Check the power switch. Make sure the power switch on the AC unit itself is turned on.
3. Check the thermostat settings. Verify that the thermostat is set to "Cool" and that the desired temperature is lower than the current room temperature. Also, ensure the system is set to "Auto" mode and not "Off" or "Fan Only."
4. Inspect the air filter. A clogged or dirty air filter can restrict airflow and cause the AC unit to malfunction. Remove the air filter and check if it needs cleaning or replacement.
5. Check the refrigerant level. Low refrigerant levels can affect the cooling capacity of the AC unit and cause it to shut off. Contact an HVAC technician to inspect the refrigerant level.
6. Inspect the outdoor unit. Go outside and check the outdoor unit (condenser). Make sure it is free from any obstructions, such as debris, leaves, or plants, which could block airflow. Also, check for any signs of damage to the unit.
7. Reset the thermostat. Try resetting the thermostat by turning it off and then back on.
8. Contact a professional. If you have gone through all the above steps and the central AC unit is still not working, it is best to contact an HVAC technician for further assistance.
