[mam209]

First, I really want to express thanks for all the expert answers that helped on my last question. You guys rock! The advice worked like a charm! I tried replacing the thermostat before cleaning the flame sensor and now the A/C is not working!! The wiring on the old stat is R,B,W,Y,G and the new Honeywell is Rh,Rc,W,Y,G. I connected the obvious ones and then the R to th Rh terminal and the B to the Rc terminal. The furnace works great( now that the flame sensor is clean ) but I cannot get the A/C to work. I have the same question in with the Honeywell people, but have not gotten an answer yet. Plus I wanted to compare what you guys say to check for their accuracy! Any help is once again greatly appreciated!

[letmetellu]

If you don't have a heat pump it sounds like you may be using the
B wire in the wrong place. I really don't know what the B wire goes to, so I will tell you how I think it should be wired.

R to Rh

W to W

G to G

Y to Y

Then if you do not already have a jumper from Rh to Rc you need to add one.

Since I don't know what the B wire does I don't know what to tell you to do with it. It could just be an extra. But I don't think it goes to the Rc terminal.

Look at the low voltage strip in the furnace and see what the B wire goes to and let me know. Then maybe I can tell you.

[mam209]

Thanks letmetellu! I traced the blue wire and it is a dummy like me! Your answer was perfect! Identical to Honeywell's as well! Many thanks for the expert advice! Everything works great!