Do not know which wire to convert to the "c" post.


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Old 04-22-14, 06:27 PM
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Do not know which wire to convert to the "c" post.

I am replacing a Honeywell model T8602C thermostat with a model RTH6500WF Wi-Fi Series. The furnace is a LENNOX G61MP Series gas furnace with a LENNOX air conditioning unit.
The problem is that I only have four wires in the wall and each are connected as follows:
Old thermostat New thermostat
W white Wl white
G green G green
R-Rc red R-Rc red
C ? and according to instructions the new one will not work with out the C post filled. The old one does not have a C post. Which wire can I use and do I have to do it with a jumper?
 
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Old 04-22-14, 06:33 PM
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Use the green wire for C.

At your stat: move the green wire from G to C.

At your furnace: move the green wire from G to C and then place a small piece of wire to serve as a jumper between the G terminal and the Y terminal. It should be the Y terminal that your thermostat Y is connected to (it looks like you may have a factory jumper between Y1 and Y2)

http://i151.photobucket.com/albums/s...nnoxG61MPV.jpg
 
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Old 04-22-14, 08:18 PM
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Thanks photobudket, your advice seems to work. Appreciate it.
 
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Old 04-22-14, 09:21 PM
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You are welcome.

My name is Carlos. Photobucket is the site that I use to post pics.

Have a good evening.
 
 

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