[whjbiii]

My old thermostat had six wires, blue, red, green, white, yellow, and black. But my new Honeywell RTH110B none programmable thermostat only gives instructions for wiring up to 5 wires. The connections are Rh Heating power supply, Rc Cooling power supply, W Heating signal, Y Cooling signal, G fan. How do I wire my new thermostat using the six wrires previously used in my old thermostat?

Sincerely, WHJBIII

[tkrussell]

Really need more detail, such as the model # of the old stat, and/or the purpose of the existing wires, so we can determine where the remaining wires go.

You may have two power sources that will put one wire on Rc and one on Rh. This still leaves one wire with no terminal.

You may have a heat pump, or some other function that the new stat is not set up to do.

The blue wire typically is used as a common for the 24 volt power source, and is brought to a stat to allow a builtin clock , or some other function the stat needs to run. Or the blue wire can be a for a reversing valve on or auxiliary heat for a heat pump.

Get back with more detail, and someone here should be able to help.

[miki1043]

I have 8 wires on my old trane bay28x139 thermostat. I'm trying to put in honeywell rth110b which only has 5 wires