Troubleshooting Guide - Honeywell Programmable Thermostat Owner's Manual

IF...
Display will not come on.
Display flashes during programming.
Display flashes during operation.
Program is lost due to power outage.
Temperature change occurs
at the wrong times.

TROUBLESHOOTING GUIDE

THEN...
Check that heat or cool system power is on. If you use batteries,
replace with fresh ones.
Make sure thermostat is correctly mounted on base.
You have reached the temperature setting limit. The setting range is
7° C to 31° C. In models with automatic heat-cool changeover, the
COOL temperature setting must be at least 2° C above the HEAT
temperature setting.
Programming has been lost because of a power outage. You must
reprogram.
Check that backup batteries are installed correctly. Replace if
necessary. Reprogram the thermostat.
Check the program times for the period in question.
Be sure that AM and PM indications are correct. Make sure the
current day and time are correct. Reprogram if necessary.
If using Programmed Recovery, remember that the furnace or air
conditioner comes on before the WAKE and RETURN start times so
the house will be at the desired temperature when the period starts.
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