No heat in braselton. Check and find master bedroom gas furnace #3 fail due to fail thermostat. Replace Tstat with nest customer provided and replace upstairs Honeywell tstat customer provided. Test both Tstat and bout operating at this time. Test gas furnace and find gas Lennox 13 year old furnace operating with weak flame sensor, weak capacitor, and under temperatures. Suggest repair for system. System missing in line water protection in attic. Suggest Comfort control maintenance plan.