I currently have two zones for cooling only and the thermostat wires are red, blue and white. The red is labeled Rc which is easy, the white is labeled W Heat (this doesn't make sense to me) and the blue is labeled cool? What I think I need to do is connect the red to the Rc on the thermostat, the blue wire (cool) to the Y, cooling connection and the white is where I am confused, it will either go to W or to G for Fan?? Why its labeled to W Heat is throwing me off.

Thermostat model numbers?
Why are you changing thermostats?
Did the original system work OK?

The old ones are Robertshaw, not sure of the model number the new one is the honeywell Rth6500B. The old ones are shot and I wanted to put programmable ones in for efficiency

The old ones are shot

IT does not make a difference if it is shot or not.
Did you follow the directions with the new thermostat about labeling the old thermostat wires designations and colors?

If not you may have to trace back all wires to see where they go on the operating controls.

OLD thermostat model number??
I will see if I can locate a wiring diagram for the old thermostat without it I can be of no help.

Yes, the wire label designations for the white is W Heat, for the Red it is Rc and for the Blue all it said was Cool. I am currently in the office now and not in front of it however that's all they said. The model of thermostat is the 200 series from what I can tell by looking online. IThe builder 9 years ago wasn't very specific on many things. Those labels were in black in on the thermostat.

I really appreciate your help by the way.. I am sure I can figure it out just don't want to risk shorting something out, but think I will be OK as long as the Red Rc is connected to the Rc on the thermostat. Then I can try the others? Any thoughts on that?

The B and W are to open and close the damper valves, I just don't know how that translates to the new thermostat.

I woulkd wire the new thermostat just the way the old one was wired. If uncomfortable with the situation I would seek professional help.

The B and W are to open and close the damper valves, I just don't know how that translates to the new thermostat.

I have no idea how it was wired to start with butif Band W are active on the old stat you might have the wrong new stat to start with.

Thanks I actually did some more research and I have the Robertshaw TX400 and the coding is as follows:

w = heat
r = common
b = cool


Can I ask you one more quick thing? The R = Common does that mean I should not conenct it to Rc? I think this goes to Rc, and then I will connect w to heat and b to y on the new one which is cool. By the way this site is great and I appreciate your help.

Rc means R (cooling), Rh means R Heating), when Rh is connected to Rc, you get R.

Rc is sometimes factory jumped ro Rh in some thermostats. Rh and Rc are necessary when there are two transformers, i.e. 1 for heat and 1 for cool.

R(whatever) goes to one side of the transformer.
C, if present goes to the other.

Power between C and R(whatever) powers the thermostat. It has not been clear in the thermostat instructtions which two terminals provides power, but it's probably Rh and C.