[dsa99]

I'm trying to install a rth230B, but my wiring connection choices do not match up with my current T-stat wires. Note: My current digital T-stat is a power sharing model (ie. no batteries) and the rth230b uses batteries, so I have that difference right out of the box. I have a single stage gas furnace and single stage condensing unit.

The choices on the new rth230b are : G,Y,W,Rc,Rh.
The current wires/connections on my old T-stat are: C (blue), R (red) , W1 (White), Y1 (Yellow) and G (Green).

There is no specific guidance in the instructions stating where to attach the C (blue wire) and which terminal for the R (red wire), either Rh or Rc.

As you can tell I'm quite a novice at this, so I'm reluctant to use the trial & error approach.

Thanks,DA
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[ballengerb1]

Both your old and new stat use 24 volts for power. Your new one has batteries for memory during a power failure. C is tranformer common, R is the transformer 24 volt line that gets contected to both Rc (cooling) and Rh (heating0. W1 I usually a heat relay for a heat pump. Y1 is your cooling relay and G is your fan relay. This site should be some help customer.honeywell.com/Techlit/pdf/69-0000s/69-1800.pdf

[dsa99]

Thanks for the help, I have read the Honeywell instructions too. But I'm still unsure where to attach the blue wire that is now attached to the C on my old T-stat. There is no C terminal on the rth230b.
Also, when you say connect the R (red wire) to both the Rc & Rh, do you mean connect it to the Rh and use a jumper to the Rc?
Thanks again,DA

[labman]

The new thermostat doesn't need the blue, leave it disconnected. And yes, jumper the RH and RC so both have power from the red wire.