Honeywell RTH6400 - Troubleshooting System Response; Heating;Cooling System Not Responding; Flashing Cool On;Heat On Messages

RTH6400 Programmable Thermostat
21 69-2211EF—05
In case of difficulty
Heating or cooling
system does not
respond
• PressSYSTEM button to set system to Heat. Make sure the temperature is
set higher than the Inside temperature.
• PressSYSTEM button to set system to Cool. Make sure the temperature is
set lower than the Inside temperature.
• Checkcircuitbreakerandresetifnecessary.
• Makesurepowerswitchatheating&coolingsystemison.
• Makesurefurnacedoorisclosedsecurely.
• Wait5minutesforthesystemtorespond.
“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 14).
Other problems • Iftheabovemeasuresdonotresolvetheproblem,checktheInCaseof
Difficulty section in your thermostat Installation Guide .