Furnace thermostat repair is necessary when the round Honeywell thermostat goes bad and turns your house into a meat locker; it is the sub base that burns out.
The furnace thermostat is simple to replace, usually only four wires and all color coded so any homeowner can change their own.
If your thermostat has more than four wires I suggest you contact a heating professional for proper instructions.
Typically in a residential heating system the colors of the wires go as follows:
Red is the hot wire from the transformer that powers the controls in the furnace and it goes to the ‘R’ screw.
White is the heating cycle wire and when connected to the red tells your furnace to heat the house and it goes to the ‘W’ screw.
Green is the fan control and when connected to the red tells your furnace fan to run and it goes to the ‘G’ screw.
Last and this time of the year sure not the least is the ‘Y’ screw. Seeing as most four-conductor low voltage cable does not have a yellow wire one must use the last wire available and that is usually blue.
If you have any doubt as to the colors of the wires I suggest you do not guess at hooking up wires to make the furnace operate. Always consult a professional to prevent you from harming your furnace or endangering your life.
Note: turn the switch on the furnace off before working on the thermostat to prevent any other problems from occurring.