Honeywell RTH2300B1038/E1 Owner's Manual page 6

Alternate Wiring
If wires will be connected to both R and Rc terminals, remove metal
jumper.
Do not use C or X. Wrap bare end of wire with electrical tape.
If you have a heat pump without auxiliary/backup heat connect O or B,
not both. If you do not have a heat pump, do not connect B. Wrap bare
end of wire with electrical tape.
Place a jumper (piece of wire) between Y and W if you are using a heat
pump without auxiliary/backup heat.
7 Install Batteries
Install two AAA alkaline batteries.
4
B O G Y
RTHXXXX
Back of thermostat
6
4
R Rc
M32734
M32707