Greetings:

Replaced a thremostat - it had died but the outside cooling unit stopped working last year. My question is: The thermostat has three wires going out to the outside unit. The old thermostat had two wires wired together - a red one and a green one. The green may not have originally been green as its very old wire. Anyway. The new thermostat said to split the two wires so I did. On the outside unit there is just two blue wires - one has the white wire from the thermostat tied to it and the other blue has the green tied to it and the red is loose. Do I need to connect the red to the green wire on the outside unit so the compressor will run? Since it had no tape or cap on it - I wonder if it did not just come loose from the green wire? Please just email your answer to [email protected]

Thanks for your help.

Robert

Check for 24 volts on the wires at the outside unit when the thermostat is calling for cooling. Those are the two wires you want to use.