An AC that runs but isn’t cooling usually means airflow is restricted or the refrigerant charge is off. Most often, the system can’t shed heat outdoors because components are dirty or pressure levels aren’t where they should be. Other possibilities are incorrect control settings or a mechanical fault that lets the fan run without real cooling. A good technician will verify airflow and refrigerant pressures rather than replacing parts blindly. We solve issues like this every week for homes across Montgomery County.
Try these quick checks before you call:
- Set the thermostat to Cool and Auto (not On for the fan).
- Replace a dirty return filter.
- Clear leaves and debris at least 2 feet around the outdoor unit.
- Look for ice on the refrigerant lines or very weak vent airflow.
If warm air continues after these steps, turn the system off and schedule a professional diagnostic to prevent compressor damage.
Updated: 2026-09-23
Need help in Rockville, MD? Call (410) 593-1980 or book online.