Instructions / Assembly

RTH6400
25 69-2696ES—01
Troubleshooting
SETUP WIRING ASSISTANCE TROUBLESHOOTING
If you have difficulty with your thermostat, please try the
following suggestions.
Most problems can be corrected quickly and easily.
Display is blank • MakesurefreshAAalkaline
batteries are correctly installed (see
page 8).
Temperature
settings do not
change
Make sure heating and cooling
temperatures are set to acceptable
ranges:
• Heat:40°to90°F(4.5°to32°C).
• Cool:50°to99°F(10°to37°C).
Cannot change
system setting
to Cool
• CheckFunction 1: System Type to
make sure it is set to match your
heating and cooling equipment (see
page 14).
Fan does not
turn on when
heat is required
• CheckFunction 3: Heating Fan
Control to make sure it is set to
match your heating equipment (see
page 16).
Heating and
cooling
equipment
running at the
same time (or
heat does not
turn off)
• CheckFunction 1: System Type to
make sure it is set to match your
heating and cooling equipment (see
page 14).
• Grasp and pull thermostat away from
wallplate. Check to make sure bare
wires are not touching each other
(see page 6).