5 FEATURES ........................................................................................................................................................ 6 KEYBOARD AND DISPLAY DESCRIPTION .................................................................................................... 7 Keyboard ............................................................................................................................................................ 7 Display ............................................................................................................................................................... 7 ADAPTIVE INTELLIGENT RECOVERYTM CONTROL ..................................................................................... 10 Optimum Comfort and Energy Savings ............................................................................................................. 11 OPERATING YOUR THERMOSTAT ................................................................................................................. 13 Setting System and Fan Keys ............................................................................................................................ 13 Setting the System Key .................................................................................................................................. 14 Setting the Fan Key ........................................................................................................................................ 14 Setting Temporary Temperatures ....................................................................................................................... 15 Changing Temperature to Temporary Setting Until Next Schedule Period ..................................................... 15 Changing and Holding Temperature Setting Indefinitely ................................................................................ 17 Changing Temperature Setting Until a Designated Day and Period (Vacation Hold) ..................................... 18 Replacing the Batteries ...................................................................................................................................... 21 3 69-1536–3 Contents (Cont) Contents (Cont) (Information) Key ......................................................................................................................... 23 Display Current Setting ................................................................................................................................. 23 Display or Reset Filter Timer Settings .......................................................................................................... 24 SETTING THE CLOCK...................................................................................................................................... 25 Set Current Day and Time ................................................................................................................................. 25 Daylight Saving Time ......................................................................................................................................... 27 PROGRAMMING YOUR THERMOSTAT .......................................................................................................... 28 7-Day Program and Operation ........................................................................................................................... 28 7-Day Preprogrammed Schedule ................................................................................................................. 29 Customizing Your Own 7-Day Schedule ....................................................................................................... 30 Programming the First Day ........................................................................................................................... 31 Copying a Day .............................................................................................................................................. 36 Clearing a Program Period ........................................................................................................................... 39 TROUBLESHOOTING....................................................................................................................................... 41 WARRANTY ...................................................................................................................................................... 43 CUSTOMER ASSISTANCE ............................................................................................................................... 45 4 69-1536–3 USING THIS GUIDE The T8665A is a multi-functional thermostat. This means it can be used in single or multi-zone applications. The following symbols will help you identify the features that apply to your system: – Triple layer of thermostats with the word, zoning, below. ...