The answer to a zone control system not working is that there could be a few common causes, such as a faulty thermostat, wiring issues, or problems with the zone dampers or control board. Symptoms may include uneven heating/cooling, rooms not maintaining set temperatures, or the system not responding to zone control commands.
Some potential solutions include checking the thermostat batteries and settings, inspecting wiring for damage or loose connections, and verifying the proper operation of zone dampers. However, if the issue persists or you're unsure of the cause, it's best to call in a professional HVAC technician to diagnose and repair the problem.