Troubleshooting Guide - Honeywell T8631A Owner's Manual

IF...
Display will not come on.
Display flashes during programming.
Display flashes during operation.
Program is lost due to power
outage.
Colon in display does not flash.
Temperature change occurs
at the wrong times.
Heating will not come on.
Cooling will not come on.
The building is too warm or too cool.
Display says HEAT ON or system
light is on, but no heat is coming
from the registers.
Display flashes REPL BAT or
goes blank when power is turned off.

TROUBLESHOOTING GUIDE

THEN...
Check that heat or cool system power is on. You need 24V from R to C
terminals.
Make sure thermostat is correctly mounted on subbase.
You have reached the temperature setting limit. The setting range is
45 F to 88 F.
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 for 24V from R to C terminals on the subbase.
Make sure thermostat is mounted correctly on the subbase.
Check for
system for the command that is bypassing the thermostat program.
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.
Remember that with Adaptive Intelligent Recovery the heating or
cooling system comes on before the WAKE and RETURN start times
so the house will be at the desired temperature when the period starts.
Check if T8631A is set for Conventional Recovery (
Check the fuse or circuit breaker and replace or reset if necessary.
Check that switch on thermostat is set to HEAT.
T8631R has a built-in time delay which can add to time delays in the
heating equipment. Allow up to 10 minutes after changing the setting
before the compressor starts.
If temperature setting is higher than current temperature, and display
says HEAT ON or SYSTEM light is on, contact your heating and air
conditioning contractor.
Check the fuse or circuit breaker and replace or reset if necessary.
Check that switch on thermostat is set to COOL.
The thermostat has a built-in time delay, which can add to time delays in
the cooling equipment. Allow up to 10 minutes after changing the setting
before the compressor starts.
If temperature setting is lower than current temperature, and display says
COOL ON or SYSTEM light is on, contact your heating and air
conditioning contractor.
Press PRESENT SETTING to check the current temperature setting.
If desired, change the time or temperature setting. See page 21.
Check for
system for the command that is bypassing the thermostat program.
Allow time for the heating equipment to heat up before
checking for heat at the register.
Install fresh AAA alkaline batteries. See page 23.
on display screen. If is present, check your external
or Adaptive Intelligent Recovery.
on display screen. If is present, check your external
visible on display)
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