I tried to replace my digital manual Honeywell thermostat that is only 6 months old (new construction) with a programable thermostat. I followed the instructions marking the wires and connecting them up...
Your "R" terminal is basically your "hot" and your "C" terminal is basically your "neutral" to simplify explanation. The Furnace supplies the "R" power to the thermostat and then depending on what wire the thermostat sends the power back on determines what the system does. The thermostat terminals are as follows "G" is fan, "W" or "aux" is elect heat, "Y" tells the outdoor unit to run, "O" or "B" tells the outdoor unit whether it is heating or cooling, and "E" is emergency heat. "G" should connect from the t-stat directly to the furnace and go no further. "W" or "aux" AND "E" should both connect to your "W" or "W1" terminal in the furnace, there should also be a "W" connection to the heat pump ( this allows the H/P to turn on the elect heat when the unit defrosts) "Y" and "O" or "B" may or may not connect to a terminal in the furnace, usually they just pass through the furnace from the t-stat to the H/P and get wire nutted in the furnace. Now, here is the key. As I mentioned previously "O" or "B", a system will only use one or the other. The entire industry (except for Rheem and Ruud) uses the "O" terminial which has 24v on it when you are cooling and no power when you are heating. Rheem and Ruud use the "B" terminal which is just backwards, 24v in heating and no power in cooling. This is all for a heat pump, If you do not have a heat pump, then disregard the references to "O", "B", "E", and "aux". You will have R-power on red wire, W-heat signal to furnace, G-fan signal to furnace, and "Y" cool signal to outdoor unit.
Jun 08, 2008 |
Honeywell Air Conditioners