The answer to 'why is my zone control system not cooling' is that there could be several common causes, such as a problem with the thermostat, airflow issues, or a refrigerant leak. Symptoms may include uneven cooling, the system running constantly, or the home not reaching the desired temperature. Solutions can range from adjusting the thermostat settings to calling an HVAC technician to diagnose and repair the issue.
If the zone control system is not cooling properly, it's best to first check the thermostat and ensure it is set correctly. Make sure the temperature setting is lower than the current room temperature. You can also try cleaning or replacing the air filters to improve airflow. However, if the problem persists, it's likely due to a more complex issue that requires professional diagnosis and repair, such as a refrigerant leak or a problem with the zone dampers or control board.