Operation Manual
Page 3
... system setting (heat/cool 8 Using program schedules 9 Program schedule overrides 12 Auto Changeover 14 Built-in compressor protection 16 Smart Response® Technology 18 RTH6400 Programmable Thermostat Appendices Battery installation 18 Customer assistance 19 In case of difficulty 20 Limited warranty 22 This...
... system setting (heat/cool 8 Using program schedules 9 Program schedule overrides 12 Auto Changeover 14 Built-in compressor protection 16 Smart Response® Technology 18 RTH6400 Programmable Thermostat Appendices Battery installation 18 Customer assistance 19 In case of difficulty 20 Limited warranty 22 This...
Operation Manual
Page 4
... and temperature setting. • Removable battery holder for fast, easy replacement. • Built-in compressor protection. 69-2211EF-05 2 Operating Manual About your new Honeywell thermostat. Features • Separately programmable weekday, Saturday, and Sunday schedules. • One-touch temp control overrides program schedule at any time. • Large, clear, backlit display is easy...
... and temperature setting. • Removable battery holder for fast, easy replacement. • Built-in compressor protection. 69-2211EF-05 2 Operating Manual About your new Honeywell thermostat. Features • Separately programmable weekday, Saturday, and Sunday schedules. • One-touch temp control overrides program schedule at any time. • Large, clear, backlit display is easy...
Operation Manual
Page 5
RTH6400 Programmable Thermostat This thermostat is ready to go . Set time and day (required for proper operation See page 6 2. Select system setting (Heat/Cool): Preset to Heat To change if needed: 1. Then check the settings below and change , see page 8 4. Select fan setting (Auto/On): Preset to go ! Your new thermostat is set the time...
RTH6400 Programmable Thermostat This thermostat is ready to go . Set time and day (required for proper operation See page 6 2. Select system setting (Heat/Cool): Preset to Heat To change if needed: 1. Then check the settings below and change , see page 8 4. Select fan setting (Auto/On): Preset to go ! Your new thermostat is set the time...
Operation Manual
Page 7
RTH6400 Programmable Thermostat Quick reference to display screen Current inside temperature Low battery warning (see page 15) Current time/day (see page 6) Smart Response® technology in effect (...
RTH6400 Programmable Thermostat Quick reference to display screen Current inside temperature Low battery warning (see page 15) Current time/day (see page 6) Smart Response® technology in effect (...
Operation Manual
Page 8
... the SET DAY button, then press s or t to set the clock time. 2. Press DONE to save & exit. Note: If the display flashes Set Clock, the thermostat will follow your settings for the weekday "Wake" time period until you reset the time and day. Operating Manual Set the time and day Press...
... the SET DAY button, then press s or t to set the clock time. 2. Press DONE to save & exit. Note: If the display flashes Set Clock, the thermostat will follow your settings for the weekday "Wake" time period until you reset the time and day. Operating Manual Set the time and day Press...
Operation Manual
Page 9
If set to select Auto or On. Select the fan setting Set Clock/Day/ Schedule Fan Auto System Heat M28405 Set Clock/Day/ Schedule Fan System On Heat M28406 RTH6400 Programmable Thermostat Press the FAN button to "On," the fan runs continuously. 7 69-2211EF-05 In "Auto" mode (the most commonly used setting), the fan runs only when the heating or cooling system is on.
If set to select Auto or On. Select the fan setting Set Clock/Day/ Schedule Fan Auto System Heat M28405 Set Clock/Day/ Schedule Fan System On Heat M28406 RTH6400 Programmable Thermostat Press the FAN button to "On," the fan runs continuously. 7 69-2211EF-05 In "Auto" mode (the most commonly used setting), the fan runs only when the heating or cooling system is on.
Operation Manual
Page 10
...-2211EF-05 Press the SYSTEM button to select Heat, Cool or Off. • Heat: Thermostat controls only the heating system. • Cool: Thermostat controls only the cooling system. • Off: Heating and cooling systems are off. • Auto: Thermostat automatically selects heating or cooling depending on the indoor temperature. To prevent possible compressor...
...-2211EF-05 Press the SYSTEM button to select Heat, Cool or Off. • Heat: Thermostat controls only the heating system. • Cool: Thermostat controls only the cooling system. • Off: Heating and cooling systems are off. • Auto: Thermostat automatically selects heating or cooling depending on the indoor temperature. To prevent possible compressor...
Operation Manual
Page 11
...to the time you go to the time you awaken and the temperature you leave for the day. RTH6400 Programmable Thermostat Save money by setting program schedules It's easy to the time you return home and the temperature you want during the morning, until you want during the evening, until bedtime. WAKE 6:...00 am 62 ° Set to the time you leave home and the temperature you are away (usually an energy-saving level). RETURN 6:00 pm 70 ° Set to program your system for weekdays, Saturday ...
...to the time you go to the time you awaken and the temperature you leave for the day. RTH6400 Programmable Thermostat Save money by setting program schedules It's easy to the time you return home and the temperature you want during the morning, until you want during the evening, until bedtime. WAKE 6:...00 am 62 ° Set to the time you leave home and the temperature you are away (usually an energy-saving level). RETURN 6:00 pm 70 ° Set to program your system for weekdays, Saturday ...
Operation Manual
Page 12
... can reduce your heating/cooling expenses. (See next page to use energy saving program settings. Operating Manual Energy saving settings for maximum cost savings This thermostat is pre-set to adjust times and temperatures of each time period.) Wake (6:00 am) Leave (8:00 am) Return (6:00 pm) Sleep (10:00 pm...
... can reduce your heating/cooling expenses. (See next page to use energy saving program settings. Operating Manual Energy saving settings for maximum cost savings This thermostat is pre-set to adjust times and temperatures of each time period.) Wake (6:00 am) Leave (8:00 am) Return (6:00 pm) Sleep (10:00 pm...
Operation Manual
Page 13
...Note: You can press CANCEL PERIOD to program (Heat or Cool). Set time and temperature for each weekday time period. 5. Note: Make sure the thermostat is set your weekday Wake time (Mon-Fri), then press NEXT. 3. Press s or t to set to the system you want to eliminate unwanted.... 6. Press NEXT to set Sunday time periods, then press DONE to set the temperature for this time period, then press NEXT. 4. RTH6400 Programmable Thermostat To adjust program schedules Set Clock/Day/ Schedule Fan Auto System Heat Done Set Day Set Schedule 8:00 Set Schedule AM Heat Setting 62 Leave...
...Note: You can press CANCEL PERIOD to program (Heat or Cool). Set time and temperature for each weekday time period. 5. Note: Make sure the thermostat is set your weekday Wake time (Mon-Fri), then press NEXT. 3. Press s or t to set to the system you want to eliminate unwanted.... 6. Press NEXT to set Sunday time periods, then press DONE to set the temperature for this time period, then press NEXT. 4. RTH6400 Programmable Thermostat To adjust program schedules Set Clock/Day/ Schedule Fan Auto System Heat Done Set Day Set Schedule 8:00 Set Schedule AM Heat Setting 62 Leave...
Operation Manual
Page 14
... setting for the day. This will be lowered when you want to temporarily adjust temperature. Press to immediately adjust the temperature. Note: Make sure the thermostat is set to the system you leave for the current time period. For example, if you want to turn up the heat early in the...
... setting for the day. This will be lowered when you want to temporarily adjust temperature. Press to immediately adjust the temperature. Note: Make sure the thermostat is set to the system you leave for the current time period. For example, if you want to turn up the heat early in the...
Operation Manual
Page 15
RTH6400 Programmable Thermostat Program schedule override (permanent) Press to permanently adjust temperature. 69 75 Inside Heat Hold Setting 6:30AM Run Schedule Fan Auto System Heat Press HOLD to adjust the thermostat manually, as needed. The "Hold" feature turns off the program schedule and allows you to...you want to cancel "Hold" setting and resume program schedule. Press to control (heat or cool). Note: Make sure the thermostat is set will override the temperature settings for all time periods. M28411 Whatever temperature you set to the system you manually change it...
RTH6400 Programmable Thermostat Program schedule override (permanent) Press to permanently adjust temperature. 69 75 Inside Heat Hold Setting 6:30AM Run Schedule Fan Auto System Heat Press HOLD to adjust the thermostat manually, as needed. The "Hold" feature turns off the program schedule and allows you to...you want to cancel "Hold" setting and resume program schedule. Press to control (heat or cool). Note: Make sure the thermostat is set will override the temperature settings for all time periods. M28411 Whatever temperature you set to the system you manually change it...
Operation Manual
Page 16
When the system mode is raising the cool setting up arrow next to "cool" to show the thermostat is in Auto, the thermostat automatically selects heating or cooling depending on the same day. Press the Select Heat/Cool button to select between the heat and cool to maintain a... 3-degree separation between the cool and heat settings. While in the Auto mode, if a schedule override takes place (temporarily or permanently) the thermostat will show an up to maintain a 3-dgreee separation. For example, if the heat temperature is raised to where it gets within 3-dgrees of the cool...
When the system mode is raising the cool setting up arrow next to "cool" to show the thermostat is in Auto, the thermostat automatically selects heating or cooling depending on the same day. Press the Select Heat/Cool button to select between the heat and cool to maintain a... 3-degree separation between the cool and heat settings. While in the Auto mode, if a schedule override takes place (temporarily or permanently) the thermostat will show an up to maintain a 3-dgreee separation. For example, if the heat temperature is raised to where it gets within 3-dgrees of the cool...
Operation Manual
Page 17
... possible compressor damage, do not use Auto Changeover if the outside temperature drops below 50ºF (10ºC). 15 69-2211EF-05 Auto Changeover RTH6400 Programmable Thermostat If the cool temperature is lowered to where it gets close to the heat setting, an arrow next to heat will show the...
... possible compressor damage, do not use Auto Changeover if the outside temperature drops below 50ºF (10ºC). 15 69-2211EF-05 Auto Changeover RTH6400 Programmable Thermostat If the cool temperature is lowered to where it gets close to the heat setting, an arrow next to heat will show the...
Operation Manual
Page 19
...is active. For example: Set the Wake time to 6 am , so the temperature is reached at 6. Smart Response® Technology RTH6400 Programmable Thermostat Inside 75 6:38 In Recovery AM Cool Setting 75 Set Clock/Day/ Schedule Fan Auto Cool On System Cool M27476 Displays when Smart Response is... activated before 6 am , and the temperature to 70°. Smart Response® Technology: This feature allows the thermostat to "learn" how long the furnace and air conditioner take to reach programmed temperature settings, so the temperature is 70° by the ...
...is active. For example: Set the Wake time to 6 am , so the temperature is reached at 6. Smart Response® Technology RTH6400 Programmable Thermostat Inside 75 6:38 In Recovery AM Cool Setting 75 Set Clock/Day/ Schedule Fan Auto Cool On System Cool M27476 Displays when Smart Response is... activated before 6 am , and the temperature to 70°. Smart Response® Technology: This feature allows the thermostat to "learn" how long the furnace and air conditioner take to reach programmed temperature settings, so the temperature is 70° by the ...
Operation Manual
Page 21
...-468-1502. Battery holder Part No. 50007072-001 Cover plate assembly*.......... Or call Honeywell Customer Care tollfree at 1-800-468-1502. Part No. 50002883-001 *Use to cover marks left by old thermostats. 19 69-2211EF-05 ACubsotuotmyeorurasnseiwstathnecremostat RTH6400 Programmable Thermostat M28415 Model number xxxxxxx Date code xxxxxxx M28416 For assistance with this product...
...-468-1502. Battery holder Part No. 50007072-001 Cover plate assembly*.......... Or call Honeywell Customer Care tollfree at 1-800-468-1502. Part No. 50002883-001 *Use to cover marks left by old thermostats. 19 69-2211EF-05 ACubsotuotmyeorurasnseiwstathnecremostat RTH6400 Programmable Thermostat M28415 Model number xxxxxxx Date code xxxxxxx M28416 For assistance with this product...
Operation Manual
Page 22
Temperature settings do not change Make sure heating and cooling temperatures are correctly installed (see page 15). Operating Manual In case of difficulty If you have difficulty with your thermostat, please try the following suggestions. Display is blank • Make sure fresh AA alkaline batteries are set to acceptable ranges: • Heat: 40° to 90°F (4.5° to 32°C). • Cool: 50° to 99°F (10° to 37°C). 69-2211EF-05 20 Most problems can be corrected quickly and easily.
Temperature settings do not change Make sure heating and cooling temperatures are correctly installed (see page 15). Operating Manual In case of difficulty If you have difficulty with your thermostat, please try the following suggestions. Display is blank • Make sure fresh AA alkaline batteries are set to acceptable ranges: • Heat: 40° to 90°F (4.5° to 32°C). • Cool: 50° to 99°F (10° to 37°C). 69-2211EF-05 20 Most problems can be corrected quickly and easily.
Operation Manual
Page 23
... set lower than the Inside temperature. Other problems • If the above measures do not resolve the problem, check the In Case of difficulty RTH6400 Programmable Thermostat Heating or cooling • Press SYSTEM button to set higher than the Inside temperature. • Check circuit breaker and reset if necessary. • Make ...sure furnace door is set system to the compressor (see page 14). Make sure the temperature is engaged. In case of Difficulty section in your thermostat Installation Guide. 21 69-2211EF-05 Wait 5 minutes for the system to respond.
... set lower than the Inside temperature. Other problems • If the above measures do not resolve the problem, check the In Case of difficulty RTH6400 Programmable Thermostat Heating or cooling • Press SYSTEM button to set higher than the Inside temperature. • Check circuit breaker and reset if necessary. • Make ...sure furnace door is set system to the compressor (see page 14). Make sure the temperature is engaged. In case of Difficulty section in your thermostat Installation Guide. 21 69-2211EF-05 Wait 5 minutes for the system to respond.
Operation Manual
Page 25
... AND FITNESS FOR A PARTICULAR PURPOSE, IS HEREBY LIMITED TO THE ONE-YEAR DURATION OF THIS WARRANTY. 1-year limited warranty RTH6400 Programmable Thermostat THIS WARRANTY IS THE ONLY EXPRESS WARRANTY HONEYWELL MAKES ON THIS PRODUCT. If you may not apply to state. Some states do not allow limitations on how long an implied... warranty lasts, so the above limitation may have any questions concerning this warranty, please write Honeywell Customer Relations, 1985 Douglas Dr, Golden Valley, MN 55422 or call 1-800-468-1502. 23 69-2211EF-05
... AND FITNESS FOR A PARTICULAR PURPOSE, IS HEREBY LIMITED TO THE ONE-YEAR DURATION OF THIS WARRANTY. 1-year limited warranty RTH6400 Programmable Thermostat THIS WARRANTY IS THE ONLY EXPRESS WARRANTY HONEYWELL MAKES ON THIS PRODUCT. If you may not apply to state. Some states do not allow limitations on how long an implied... warranty lasts, so the above limitation may have any questions concerning this warranty, please write Honeywell Customer Relations, 1985 Douglas Dr, Golden Valley, MN 55422 or call 1-800-468-1502. 23 69-2211EF-05