[albertan]

I am replacing an old honeywell thermostat (2-wire) with awhite-rodgers programmable thermostat. The old thermostat wires are not marked on the thermostat and they are blue and white. The conections at the furnace (anthes) are blue TH and White TR. The new thermostat has rh rc (jumped together) w b on top and c g o y on the bottom. I think I hook blue to the rh and white to w, but I am not sure, can someone help me?

[labman]

I suppose the TH and TR make great sense to whoever decided to use them, but I am not familiar with them. If it is a voltage stealing thermostat, the way you say may work, even if it isn't right. If it isn't a voltage stealing thermostat, you must identify the common at the furnace connected to the other terminal of the transformer, and run a third wire to the thermostat connecting it to the C terminal. If you must pull in a new wire, you might pull in a standard 5 conductor thermostat cable. It would give you the option now of fan only, and would have to be done before going with A/C