I recently purchased a Honeywell RTH7500d off of ebay so when i moved into my newly purchased house that I could so some energy saving changes.

I went tonight to install new t-stat but noticed when i removed the old Lennox one from the wall taht there is only 2 wires, white & black, and the instructions for the new t-stat mentions nothing about them. Did some searhing on the net but found a lack of required information to install to this system. Please help!