Air Conditioner — No Cooling
Check cooling mode, the thermostat fan setting, filter condition, and open registers when an air conditioner is not cooling.
Start by checking the thermostat mode and setpoint, then check airflow. These non-invasive checks may identify a setting or airflow issue, but they do not determine whether the equipment itself needs repair:
- Set the thermostat to COOL or AUTO and choose a temperature below the current room temperature.
- The fan can be set to ON for continuous airflow or AUTO to run with the cooling system; lower the cooling setpoint to see whether the system responds.
- If airflow seems weak, check whether an accessible filter is extremely dirty. A clogged filter can restrict airflow; follow the filter and equipment instructions when replacing it.
- Check that supply registers are open and not blocked.
Do not open the equipment or operate electrical disconnects. If the system still does not cool after these checks, request service from a qualified technician.