Replacing thermostat for gas furnace only
Have a 2003 Fourwinds with the old style wall thermostat with the hard on/off switch and temp adjustment below with just bars (no numbers). On several occasions, the furnace will start and heat up cam...
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Those codes are more or less standard, although inscrutable to non-HVAC professionals. Often I think the colors of the wires correspond to the letters.
R is common (Rc is for cooling, Rh for heating, and if both exist there's often a jumper connecting them together).
W is heat control
Y is cooling control
G is the fan control
I don't recall offhand what B and O are generally for; one's probably the 24VAC power from the transformer, one might be for a heat pump or something like that. At any rate, you need to use W and R for the furnace operation and ignore the others. It oughtn't matter in this particular case which one goes to which connection, but red to R and white to W seems to me to be more aesthetically correct than vice-versa.
R is common (Rc is for cooling, Rh for heating, and if both exist there's often a jumper connecting them together).
W is heat control
Y is cooling control
G is the fan control
I don't recall offhand what B and O are generally for; one's probably the 24VAC power from the transformer, one might be for a heat pump or something like that. At any rate, you need to use W and R for the furnace operation and ignore the others. It oughtn't matter in this particular case which one goes to which connection, but red to R and white to W seems to me to be more aesthetically correct than vice-versa.
