Hello, I'm trying to replace my old DICO Manual Thermostat with a new Programmable HoneyWell RTH230B. There doesn't seem to be a model, part, or serial number on the old thermostat, so I can't locate any information on it via the Web (If you remove the fact place the following numbers are stamped on the wall plate: 8639 E6 4). At any rate, there are 4 wires going into the unit from the wall...they are red, blue, green and white. Can anyone help me figure out which wire goes to what? Thanks in advance...
Replace DICO Thermostat with a HoneyWell RTH230B
Oct 29, 2005
4 Replies
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Note that color coding assumes that the installer followed the standards. Many don't. If you aren't sure then check the thermostat wiring where it connects to the air handler / furnace to be sure.
How do you know if the Honeywell is even correct for the application?
4 wires could mean a plethora of different systems. Best to trace the wires down and see what they do before you go much farther.
As long as it isn't a HP, he's probably OK with that model.
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I need a lot more info than you give here is this Heat/Cool? I need model and serial of all units.
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