Other times there may be a more serious problem such as a failed part. Either way, its best to have your system checked by a licensed hvac professional to determine the exact cause of the problem as well as inspect the furnace for any other potential future problems that may arise.
We often receive calls from homeowners about their furnace not coming on and many believe it is due to a bad thermostat. More often than not, however, the thermostat is not the culprit. Todays modern furnaces will often go into lockout mode if a fault is detected while the furnace is in the heating mode. By resetting the power to the furnace, either by turning off the electrical switch to the furnace and turning it back on, or by doing so through the thermostat, the furnace will re-boot, similar to a computer. The furnace will attempt to come on, and may even start a heating cycle. But if the fault that caused the initial lockout is still present, the furnace will eventually go into lockout mode again, thus leaving you in the cold.
