Troubleshooting Tips - Honeywell RTH7400D Owner's Manual

If . . .
Display is
blank.
Temperature
settings do not
change.
Heating system
does not turn
on.
Cooling system
does not turn
on.

Troubleshooting Tips

Check that fresh AA alkaline batteries are
installed as marked on the thermostat.
Check that the temperature settings are:
• Heating 40°F to 90°F(4.5°C to 32°C).
• Cooling 50°F to 99°F (10°C to 37°C).
• Set the system to Heat by pressing the
System button.
• Check the heat temperature setting to
be sure it is set above the room
temperature and "Heat On" shows
solidly in the display.
• Check the circuit breaker to be sure it is
not tripped.
• Check power switch at heating and/or
cooling system to be sure it is on.
• Check the furnace door to be sure it is
closed securely.
• Wait five minutes for the heating system
to respond.
• If all of this was checked, contact your
local heating and cooling contractor.
• Set the system to Cool by pressing the
System button.
• Check the cool temperature setting to be
sure it is set below the room
temperature and "Cool On" shows
solidly in the display.
• Check the circuit breaker to be sure it is
not tripped.
• Check the power switch at the heating
and/or cooling system to be sure it is on.
• Check the furnace door to be sure it is
closed securely.
• Wait five minutes for the cooling system
to respond.
• If all of this was checked, contact your
local heating and cooling contractor.
59
Then . . .
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