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CT3451 PROGRAMMABLE THERMOSTAT
11 69-1620—1
TROUBLESHOOTING
Table 4. Frequently Asked Questions.
If ... Then ...
Display does not come on. Make sure the batteries are fresh and installed correctly.
Temperature display does not go lower than
40°F (4°C) or higher than 99°F (37°C during
programming.
Your thermostat has reached the temperature limit. Be sure the
setting range is from 40°F to 99°F (4°C to 37°C).
Display shows flashing or steady “bAtLo.” The batteries are low; replace them as soon as possible.
Temperature change occurs at the wrong
time.
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.
Heating does not come on. • Check that the System switch is set to Heat.
• Check the system fuse or circuit breaker and replace or reset, if
necessary.
• Check for correct wiring and good connections.
• If display is blank or displays “bAtLo,” install fresh batteries.
• Allow time for the furnace to heat up and the fan to come on
before checking for heat at the register.
• If the temperature setting is higher than the current room
temperature and the flame is displaying, the thermostat is
operating correctly. Contact a heating contractor for assistance.
Cooling does not come on. • Check that the System switch is set to Cool.
• Check the system fuse or circuit breaker and replace or reset, if
necessary.
• Check for correct wiring and good connections.
• If display is blank or says “bAtLo,” install fresh batteries.
• The thermostat has a built-in time delay on cooling. Allow five to
ten minutes after changing the setting before the air conditioner
starts.
• If the temperature setting is lower than the current room
temperature and the snowflake is displaying, the thermostat
is operating correctly. Contact an air conditioning contractor for
assistance.
The furnace cycles too frequently or the
system cycle length is too short or too long.
Adjust heat cycle rate in the Customize Your Thermostat section.
The thermostat current setting does not
match the displayed room temperature to
within plus or minus 1°.
• Plug the wiring hole in the wall behind the mounting plate with
insulation to prevent drafts that can adversely affect thermostat
operation.
• Be aware that it is normal for the current setting and the
displayed room temperature to differ occasionally.
• During recovery from setback or setup, setting and displayed
room temperatures can differ for up to 30 minutes after recovery
period.
System on indicator ( = heat; = cool) is
lighted, but no warm or cool air is coming
from the registers.
Wait five minutes after seeing the flame or snowflake and check
the registers again. If there is no hot or cool air coming from the
registers, refer to “Heating does not come on” or “Cooling does not
come on.” If everything is checked contact you heating and air
conditioning contractor.
Thermostat backlight appears dim. • Wait until Replace Battery indicator is illuminated and replace
batteries.
• Replace batteries now.
System on indicator is flashing.
• MInimum off-timer is in effect. Wait five minutes until the
minimum off-timer is complete.