The old thermostat (round old dial) has 3 wire red, blue, white but the new honeywell RTH230B1006 is a single stage 5-2 unit and it has a lot of connections! Which go where? Or did I buy the wrong unit?:confused:

OLD: Red, White and Blue
NEW: Rh Rc W Y G

I have both a gas furnace and central air. Please help! The other posts did not have the answers.

Jumper wire between RC-RH and hook the red wire to one of them, White wire needs to go to the "W" terminal , and blue will go to the "Y" terminal, but you are missing a wire, you will need an extra wire for the fan, this is usually a green wire, and it will go to the "G" terminal.

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Originally Posted by novice renovator

The old thermostat (round old dial) has 3 wire red, blue, white but the new honeywell RTH230B1006 is a single stage 5-2 unit and it has a lot of connections! which go where? Or did I buy the wrong unit?:confused:

OLD: Red, White and Blue
NEW: Rh Rc W Y G

I have both a gas furnace and central air. Please help! The other posts did not have the answers.

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That info is extremely helpful, however "add an extra Fan wire?" how do I do this?

How many wires do you have coming from the wall? I doubt there are just three, in order for the blower on the furnace to engage the thermostat has to send 24 volts to the furnace through the "G" terminal.