What Do the Codes Mean on a Honeywell Digital Thermostat?

Some, but not all, Honeywell digital thermostats use codes to indicate the current function as you make changes to your thermostat's advanced settings. Other Honeywell digital thermostats don't use codes at all. If your Honeywell thermostat is one of the models that uses codes, knowing what these codes mean lets you program your Honeywell thermostat without confusion. Press the up and down arrows to display the different options.

Date and Time Settings

The "0120" code indicates that you can change the first two digits of the year setting. The "0130" code means that you can change the last two digits of your thermostat's year setting. The "0140" code means that you can change the current month setting on your Honeywell thermostat. The "0150" code means that you can change the current date setting on your thermostat by pressing the arrows until the correct date ("01" through "31") is displayed.

Schedule Settings

The "0160" code means that you can turn your Honeywell's programmed schedule on (option "4") or off (option "0"). The "0540" code means that you can change the number of daily program periods you can program into your thermostat. Option "2" allows two periods (Wake and Sleep) and option "4" allows four periods (Wake, Leave, Return and Sleep).

Backlight Setting

The "0280" code means that you can change the setting for your Honeywell digital thermostat's backlight. Option "0" will turn on the digital thermostat's backlight for 45 seconds after you have pressed a key. Option "1" keeps the backlight on all the time at low intensity, bringing it to full brightness when you press a key.

Display Settings

The "0320" code means that you can change whether your digital thermostat displays Fahrenheit (option "0") or Celsius (option "1). The "0640" code means that you can switch between a 12-hour-clock format (option "12") and a 24-hour-clock format (option 24).

Daylight Savings Time Setting

The "0330" code means that you can change your thermostat's Daylight Savings Time settings. Your Honeywell digital thermometer will automatically change the time setting to accommodate Daylight Savings Time when you select option "1" or "2." Option "1" uses the Daylight Savings Time schedule that was in effect through 2006. Option "2" uses the Daylight Savings Time schedule that came into effect in 2007. Option "0" sets your thermostat to not adjust the time for Daylight Savings Time at all.

Furnace Filter Change Reminder

The "0500" code means that you can set your digital thermometer to display an alert at a specified interval, reminding you to change your furnace filter. Select the option by pressing the up and down arrows. Option "0" shows no reminder and options "1" through "14" display a reminder after various time periods. The "E" option sets the alert to display automatically when optional equipment indicates that the furnace filter needs to be changed.

Humidifier Pad Reminder

Code "0510" means that you can set your digital thermometer to display an alert at a selected interval, reminding you to change your humidifier pad. Option "0" turns this feature off. Options "1" through "3" display a reminder after various time periods. Option "E" sets the alert to display automatically when optional equipment indicates the humidifier pad needs to be changed.

UV Lamp Reminder

Code "0520" means that you can set the thermostat to display an alert reminding you to change the ultraviolet lamp. Option "0" turns this feature off. Option "1" displays a reminder after one year, and option "2" displays a reminder after two years. Option "E" sets the alert to display automatically when optional equipment indicates that the UV lamp needs to be changed.

Adaptive Intelligent Recovery Setting

The "0530" code means that you can turn your thermostat's Adaptive Intelligent Recovery on (option "1") and off (option "0"). This feature lets the thermostat learn how long it takes your furnace to heat your home to the desired temperature so it can turn on the heat in time to reach the specified temperature at the specified time.

Screen Lock

Code "0670" means that you can change the screen lock settings to keep someone from reprogramming the thermostat. Option "0" unlocks the screen. Option "1" locks all the thermostat functions except for the "Cancel" key and the temperature controls. Option "2" completely locks the thermostat screen.