Operating Manual
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
No response to
key presses (or
temperature will
not change)
Backlight is dim
• 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 AAA alkaline
batteries are correctly installed (see page 20).
• Check to make sure the thermostat is not locked (see page 25).
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)
• If thermostat is battery powered, make sure fresh AAA alkaline
batteries are correctly installed (see page 20).
• If thermostat is AC powered, a dim display is normal. The backlight
remains on at a low level, and brightens when a key is pressed.
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