Honeywell 85-3126 Thermostat User Manual


 
Operating Manual
24
If you have difficulty with your thermostat, please try the following.
Most problems can be corrected quickly and easily.
Display is blank Check circuit breaker and reset if necessary.
Make sure power switch at heating & cooling system is ON.
Make sure furnace door is closed securely.
No response to
key presses (or
temperature
does not
change)
Check to make sure the thermostat is not locked (see page 18).
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)
Backlight is dim 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.
Troubleshooting