What wiring does the RTH5160 thermostat support?

The RTH5160 supports R, Rh, Rc, Y, G, C, O/B, W, W2, E, A, K, and Aux terminals. It does NOT support L/A, S, or U terminals. For conventional systems, the thermostat accommodates either 1 R-wire or 2 R-wires (R/Rh and Rc) with the R-switch set accordingly. The C terminal does not power the display or operations—batteries are always required. If you have wires in unsupported terminals, contact Honeywell support at yourhome.honeywell.com/support.