In Case Of Difficulty - Honeywell RTH7400 series Operating Manual

About your new thermostat

In case of difficulty

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 heating and cooling temperatures are set to acceptable ranges:
No response to
key presses (or
temperature will
not change)
• Check circuit breaker and reset if necessary.
• Make sure power switch at heating & cooling system is on.
• Make sure furnace door is closed securely.
• If thermostat is battery powered, make sure fresh AA alkaline
batteries are correctly installed (see page 19).
• Heat: 40° to 90°F (4.5° to 32°C).
• Cool: 50° to 99°F (10° to 37°C).
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RTH7400/RTH7500 Series
69-2222ES—05