Intertherm has wiring of E,O,G,R,C,Y,W all have wires to them and changing to honeywell it has Rh,Rc,W,Y,G Where do all the wires go?

A thermostat is a switch. It connects 24vac from one terminal to another depending on the request. The 24vac comes from a transformer, usually located in the furnace and connects to the R terminal. Since you are using RH and RC without a jumper between it means there are two transformers, one in the furnace for heating (RH) and one in the air conditioner condenser used for cooling (RC).
Your old thermostat was probably mechanical and did not have a C (24vac common) terminal. Your new thermostat requires power to operate therefore needs a wire connected to a C terminal. I would get rid of the transformer you added and look for an unused wire in the bunch at the thermostat. If it's there connect it to C on the thermostat and to C on the furnace. Remove any jumper from R to RC or from RH to RC depending on your thermostat and connect wires same as the old thermostat.

RH is red heat and RC is red cool, red being the "hot leg" of the 24 volt control voltage, normally you will have a jumper from RH to RC, the fact there is an RC tells me there must be an RH too?
I will look after this post and come back if any new info was found, other wise I will say call 1800 Honeywell and provide you a diagram to check out.

rh is hot for heating rc is hot for cooling looks to me like ya need a heat pump stat some thing to control the reversing valve.Tom

You have caught me without my old books, but I can tell you the orange wire is for the reversing valve on a heat pump. Almost all manufacturers, except for Lennox, are: R=Power (24volts), G=Indoor fan (Blower), Y=Cooling (A/C), and W=Heat. Some t'stat's are set up to use 2 separate transformers (24 volt), that is why you will see Rc, Rh. This is power for cooling and power for heating. If this is what you have, just take the Red wire and strip it back far enough to go under both screw terminals if the unit is a residential one. I've been doing commercial work for over 20 years and have never seen an "A" terminal, so I can't help you there. You may want to double check that. If I'm reading you correctly, I would put the orange wire on the "O" terminal. Don't understand why the "Y" terminal is not used. It turns on the compressor. The "O" goes to the reversing valve to "Tell" the outdoor unit that it is either in the cooling or heating mode.

Good Luck and let me know if I can help any further.

You need to go into the installer setting to change it from heatpump to single stage gas heat.Go to www.honeywell.com if youve lost them.

Yes, I believe that you will be fine. If the original wiring is correct then I have listed the basic wiring below. As always read the directions and make sure the wiring matches your system.

Red wire = Rh (24v power, should have an exsisting jumper to RC)
White wire = W (heat mode)
Yellow (or sometimes blue) wire = Y (A/C)
Green wire = G (Indoor Fan)

I jumped the rc and rh wires in the therostat box and now have fan only when selected.

I have my temp on C and I need to change back to F I have the RTH230B programable

rh and rc should have a jumper between them.connect red to either.y=yellow g=green w=white and do not use the blue.your new stat will run on batteries.

Typically if you have a yellow wire in the "y" terminal blue is used as common or "c". As far as your jumper from rc to rh, that will depend upon what type of heat you have. If all of your heat and cooling come from your packaged unit outside, yes you will need the jumper. If this does not work maybe you have a bad breaker or transfomer.