Zone system Thermostat for upper level has failed. The thermostat does not send a signal to the zone board. I replaced the nest thermostat and tested all zones. All zones are functioning at this time. Went over equipment with homeowner and explained that this equipment is not designed for zoning and there will be premature failures due to this. At this time the system is heating and cooling properly and to its best ability to. Thank you for choosing T.E. Certified, have a great weekend!