Wiring - Honeywell RTH6400 Series Quick Installation Manual

Wiring

If labels do not match letters on the thermostat, check
the chart below and connect to terminal as shown here
(see notes, below).
If wires will be connected to both R and Rc
terminals, remove metal jumper (see page 6).
Do not connect both O and B if you have a heat
pump. Connect O wire to O/B W. Wrap B wire
with electrical tape and do not use.
Do not use C, X or B. Wrap bare end of wire
with electrical tape.
21 69-2210EF—03
RTH6400
M28418