I had a Honeywell thermostat that died, It was working fine but sometime during the summer it died, I was running the fan only to circulate the air in my home. Old house, gas furnace, 5 wire from furnace to thermostat.
I replaced it with a nest, I wired it as instructed but it didn't recognize the yellow wire as I don't have AC. wire status does not show it as connected. From the get go the main blower turns on as soon as the system calls for heat, I had the same wire connections on the Honeywell for well over a year and the main blower worked as it should coming on after the exhaust blower and ignition and heating of the heating chamber. Other than that, everything seems to work as it should. Clod air blowing during start up is annoying, but it only takes a minute or three to warm up. Is there something on the furnace that may be bad, limit switch failed in the closed position? Anyone else run into similar issues?
