Hi,

I am replacing old honeywell thermostat with rth230b model.
There are 6 wires comes from the wall. I have connecterd GYW and R to Rc.
Heat works fine. Then AC starts fan works but outside unit do not start up.
Looking at the wire diaramm looks like one I need power to Cool relay which means
Either blue or orange should go to Rc and existind R should be moved to Rh.
What should I do? Thanks

Rh and Rc should be jumpered together.

Sorry to mention this: Rh and RC are jumpered together. Also. This is gas heater with AC unit outside. Thanks

Y controls the outside unit. It's possible that the breaker popped when doing the upgrade. If your comfy, you can remove the panels from the outside unit after turning it off and watch the contactor.

If you connect Y to R, temporarily, the outside unit should start. There are delays built into the thermostat and sometimes the outside unit. They can range from 1-5 minutes before it can turn on after an off.

KISS, If I understood correctly I should not even try connecting blue or orange wire to RC? There is 5-wire connection diagram in the thermostat instruction. Do you think it does not aplpy to my case? Thanks

Bet the other wire is C. C is optional. Not necessary if stat is battery powered.

Check the AC breaker. Not the one for the heater.

I did. I actually turn Heater and AC units breakers off on the electrical panel before I did install on back on after...
Thanks

Y to Rc, should turn on the outside unit. One reason why it would not, is if for some reason you had two transformers.

What terminals were used on the old stat?

Old stat has matching GYWR and I did not label B and O :((((

If you had wires connected to B/O then you have a heat pump and your cuurnt stat won't work. It's made for gas/oil and possibly electric furnaces.

The outside unit runs in both heat and cool modes if you have a hP.

There is no HP it is just AC unit. Outside unit does not run at all now. Thanks

Besides the tests I told you to do, I'm out of options.

a) There is a rare case where there are two transformers - Rc and Rh went to different wires.

If you temporarily connectt R to Y, this rues out the stat.

If your able to observe the contactor in the AC unit, this rules out the wiring.

Thanks - I'll try those tests. There is also second stat upstaires which I did not screw up yet - I am going to look at the wiring there.
Thanks again.