Honeywell RTH8500D Owner's Manual page 27

Step 11. Configure Installer Setup (Cont)
3. Press and hold the center blank key for approximately five
seconds, until the screen changes.
4. Release the center key when the display on your thermostat
matches the display below.
TUE
CHANGE FILTER UV LAMP HUMIDIFIER PAD
Inside
SYSTEM
EM HEAT
OFF
PM
COOL
DONE
MON WED THU
DONE
27
Set To
Following
Schedule
CANCEL
FRI SAT A A T SUN
M19969
M22214
69-1725-1