The answer to 'when to service zone control system' is that you should service your zone control system at least once a year, or more frequently if you notice any issues. Regular maintenance will help ensure your HVAC system is running efficiently and prevent potential problems down the line.
During a zone control system service, the technician will check all the components, including the dampers, thermostats, and control panels, to make sure they are functioning properly. They will also clean and lubricate any moving parts, and update the software or firmware if necessary. This will help extend the lifespan of your system and keep your home comfortable.