Just as an after thought, there is no COMMON wire connected to any terminal
on your old thermostat. So if you are absolutely sure that the RED wire was
RH and the BLACK wire RC and that you have a single transformer and these
two wires were bridged Then one of these two wires can be disconnected from
the transformer ACTIVE and connected to common SAY THE BLACK WIRE this wire
can then be connected to C on the new thermostat. The wiring would then be
RED wire R transformer to R new thermostat and BLACK wire common transformer
to C on the new thermostat
"Jason" wrote in message
...
Hi guys,

I'm in need of some help.

I just bought a Robertshaw 9851i programmable thermostats (any comments?)
and I'm not quite sure how to connect everything. My current thermostat
uses the following wires:

Rh - Heat Transformer
Rc - Cool transformer
Y - Cooling Control
W - Heating Control
G - Fan control relay
O - Cool active reversing valve
B - Heat active reversing valve

The new one I just bought has these:

C - 24 VAC Common
R - 24 VAC transformer
G - Fan relay
Y1 - Cooling Relay
B - Heat active reversing valve
W1 - Heating Relay
O - Cool active reversing valve
H - Humidity relay
D - Dehumidity relay

The only thing I'm confused about is the "C" and the "R". Where do I
connect my former Heat Transformer ("Rh") to? The C or the R? Would the
Rc
go to the C? I'm just not sure because their names don't correspond and I
don't want to risk anything.

A black wire is connected to RC on the thermostat and the a red wire is
connected to RH on the thermostat.

I went and checked the furnace and both the RED and BLACK wires are
connected to "R". Does that I connect the black and red wires to "R" on
the new thermostat?

Am I way off?? Any help would be much appreciated. I've done lots of
research on the internet, but I'm getting a little confused.

Thanks in advance,

Jason