8
Troubleshooting
If you have difficulty with your thermostat, please try the following suggestions. 
Most problems can be corrected quickly and easily.
Display is 
blank 
•  Check circuit breaker and reset if necessary.
•  Make sure power switch for heating & cooling system is on.
•  Make sure furnace door is closed securely.
•  Make sure fresh AA alkaline batteries are correctly installed 
(see page 6).
Heating 
or cooling 
system does 
not respond
•  Press Mode button to set system Heat (see page 2). 
Make sure the desired temperature is set higher than the 
inside temperature.
•  Press Mode button to set system Cool (see page 2). 
Make sure the desired temperature is set lower than the 
inside temperature.
•  Check circuit breaker and reset if necessary.
•  Make sure power switch for heating & cooling system is on.
•  Make sure furnace door is closed securely.
•  Wait 5 minutes for the system to respond.
Temperature  
settings do 
not change
Make sure heating and cooling temperatures are set to 
acceptable ranges:
•  Heat: 40 °F to 90 °F (4.5 °C to 32.0 °C)
•  Cool: 50 °F to 99 °F (10.0 °C to 37.0 °C)
“Cool On” or 
“Heat On” is 
flashing
•  Compressor protection feature is engaged. Wait 5 minutes 
for the system to restart safely, without damage to the 
compressor (see page 5).