Lennox CS7000 Touch Screen Programmable Thermostat User Guide


Lennox CS7000 Touch Screen Programmable Thermostat



  • Tabbed user interface with touchscreen interaction
  • Soft blue backlighted screen with adjustable brightness
  • Equipment maintenance reminders
  • Humidification measurement and control
  • Programmable or non−programmable options
  • Automatically changes between heating and cooling

ComfortSense® 7000 Series Model L7742U Thermostat

The ComfortSense® 7000 Series Model L7742U thermostat is an electronic 7−day, universal, multi−stage, programmable, touch screen thermostat. It also offers enhanced capabilities including humidification /dehumidification/dewpoint measurement and control, Humiditrol® EDA (Enhanced Dehumidification Accessory) control, and equipment maintenance reminders.

  • Large, clear display with soft blue backlight shows the current and set temperature, day/date/time, indoor relative humidity, and outdoor temperature (if the optional outdoor sensor is used). Dehumidification measurement and control
  • Humiditrol® EDA capability Dew point adjustment control
  • Menu−driven programming guides users through the scheduling process showing only necessary information on each screen. Ergonomic design.
  • Smooth Setback Recovery starts the system early to achieve the set-point at the start of the program period.
  • Compressor short−cycle protection (5 minutes).
  • The real-time clock keeps time during power failures and automati-cally adjusts for daylight savings time and leap year.
  • Maintenance reminders let users know when to service or replace filters, humidifier pads, and ultraviolet lamps, plus two user or installer-defined custom reminders.
  • Program Hold options allow users to override the program schedule as desired by time and date.
  • Select individual days or groups of days to set programming.
  • Programmable fan offers increased performance when combined with whole-home indoor air quality products.
  • The outdoor temperature display (with an optional outdoor sensor) shows the current outdoor temperature.

Your installer has set up your thermostat based on the type of heating and cooling system and accessories that your thermostat connects to. This booklet details user settings available to you that will give you as much functionality and control as you want.

Touch Screen Display


Press the screen anywhere − the first press turns on the backlight.

  • Selection Tabs − Press to select: HOME (normal display), SCHEDULE (for programming), and OPTIONS (to set fan operation, alerts, service reminders, and other user and installer settings). B MODE − press to cycle through HEAT, COOL, AUTO (auto changeover), OFF, and EM HEAT (emergency heat).AUTO (auto changeover), both HEAT and COOL setpoints are displayed.
  • Up/down arrows are used for adjusting the temperature up or down; if in AUTO (auto changeover) mode, two sets of up/down arrows appear.
  • The information display area displays different information depending on the tab selected
  • HOME tab: displays outdoor temperature (if the outdoor sensor X2658 is installed), indoor relative humidity (RH), which mode is calling, hold settings information, and service reminders.
  • SCHEDULE tab: displays the event being programmed;
  • OPTIONS tab: displays a scrolling list of installers- and user−adjustable parameters, including filter and service reminder periods, etc.
  • Schedule time adjustment, User/Installer Settings up/down arrows:
  • HOME screen: not visible except when executing a HOLD SETTING)
  • SCHEDULE and OPTION screens: used to adjust the schedule and option settings.
  • Dynamic keys − not visible in the HOME screen unless executing a
  • HOLD SETTING. For SCHEDULE and OPTIONS settings, these keys appear and change depending on the selection. See the schedule and options sections for details.

Home Screen Current Conditions & Temperature Settings



The HOME screen (figure 2) displays indoor temperature and outdoor temperature if the outdoor sensor is installed. Another system operational information, such as indoor relative humidity (if turned on in user settings), dehumidifying, cooling, or heating, will alternately be displayed in the information display
Equipment operation information appears in the boxes along the left side of the home screen to indicate cooling or heating equipment operation the setting, and whether scheduled programming is ON or OFF. From these boxes, users can change the unit’s mode to HEAT, COOL, AUTO (auto changeover − default), EM HEAT (emergency heat for heat pump applications including dual fuel and HP with Electric Heat), or OFF. The user can also decide whether to operate the unit per the programmable schedule, or in a non−programmable mode using the SCHED box.

Controlling the Heat/Cool Modes of Operation



On initial power-up or after a power loss over 2 hours, the thermostat powers up at the HOME screen in the AUTO position. If it powers up after a power loss of fewer than 2 hours, it assumes the last mode set. Pressing MODE repeatedly scrolls through all the modes AUTO, EM HEAT, COOL, HEAT, then back to OFF. HEAT, COOL and OFF modes are as each name implies. AUTO (autochangeover) allows the thermostat to switch between Heating and Cooling, whichever mode is dictated by the indoor temperature.

EM HEAT (emergency heat) bypasses the first stage of heating (any stage[s] of heat pump heating) and goes directly to the heat stage used for maximum heating to more quickly warm a very cold house. When the indoor temperature decreases or increases, the HEATING or COOLING cycle will turn on based on the displayed mode. When the HVAC system is on, the INFORMATION DISPLAY AREA (shown in figure 3) will display one or several operational messages (listed in the table below). If the outdoor sensor is connected and is turned on in both installer and user settings, the outdoor temperature will be included in the displays. The table below summarizes the information messages When the faults, errors, and service information displays appear, dynamic keys will appear under the second line entries, REMIND, CLEAR, SERVICE, or RESET. Press the box to perform the action.



Information Display Area table



Controlling the Fan Operation


If the backlight is not on continuously, press the screen anywhere to turn it on the backlight. Press the OPTIONS tab to access the FAN mode control. Press the FAN button; repeated presses scroll through all the modes, AUTO, ON, and CIRC (circulate).

  • AUTO the fan is following schedule.
  •  The fan is NOT following the schedule and runs continuously until it is changed from the OPTIONS screen.
  •  CIRC fan is following a schedule and cycles during periods of equipment inactivity. Cycle time is dependent on user settings FAN CIRCULATE (Page 10).

If the FAN mode displays AUTO and ON or CIRC was selected during scheduling for the current period, the thermostat will indicate the current fan mode in the information display (FAN ON or FAN CIRC). In the CIRC mode, the user can cycle the fan for a programmed percentage of active time per hour, during periods of equipment inactivity (i.e., heating or cooling equipment not running). The fan is ON for 5 minutes at a time. The user may change the percentage of ON time that the fan is on (see FAN CIRCULATE [Page 10]): Fan Program The user can program the fan to be ON, AUTO, or CIRC during a program event period. While scheduling the event, if the fan is set to ON, it will remain on during the entire event. If it is set to CIRC, it will circulate during equipment inactivity per user programmable cycles (see FAN CIRCULATE, Page 10). If set to AUTO, the fan will come on with the equipment to serve the heating/cooling demand and go off accordingly.

NOTE − When the OPTIONS screen FAN mode is changed to ON or CIRC, whatever was scheduled is ignored − the fan will either be ON or it will CIRCULATE per the user−programmed intervals (USER SETTINGS − FAN CIRCULATE (Page 10). When FAN-AUTO is selected in the OPTIONS screen, the schedule IS followed. In the CIRC mode, the user can cycle the fan for a programmed percentage of active time per hour, during periods of equipment inactivity (i.e., heating or cooling equipment not running). The fan is ON for 5 minutes at a time. The user may change the percentage of ON time that the fan is on (see FAN CIRCULATE [Page 10]):

Controlling the Schedule


If the backlight is not on continuously, press the screen anywhere to turn it on the backlight. From the HOME screen press SCHED; repeated presses toggle the schedule ON and OFF. If ON, the system follows the program developed by the user (Page 7). If OFF, the system operates as a non−programmable thermostat the user must make changes when desired. The autochangeover feature continues to operate based on manual user inputs. The fan mode is displayed on the SCHEDULE screen when programming the thermostat and can be changed only during scheduled editing (after EDIT is pressed). Fan settings in the OPTIONS screen will OVERRIDE the scheduled fan operation.

Schedule tab programming
If the backlight is not on continuously, press the screen anywhere to turn it on the backlight. Press the SCHEDULE tab at the top of the screen. The display changes to programming mode (figure 4) and shows the current settings.

The thermostat may be programmed for two or four (default) events per day. The names for the events are WAKE, LEAVE, RETURN, and SLEEP. The selected time for an event to occur is based on when you want the event to begin. Four events (default) are common for working households. To change to two events per day, see page 10. When set for two events per day, the display would appear as WAKE (or SLEEP) PERIOD BEGINS”.



Programming may be performed in groups of days or individual days, as follows:

  • MON TO SUN − allows every day to be set the same.
  •  MON TO FRI (weekday programming) and SAT TO SUN (weekend programming).
  • MONDAY through SUNDAY allows individual days of the week to be programmed separately.

NOTE − After using one of the groups of days described above, the program allows you to subsequently change individual days to suit your needs. To get to the different groupings of days, press EDIT, then press NEXT repeatedly to scroll to the desired grouping.

Programming Complexity
The programming process for groups of days or individual days is the same, except for the amount of time required to go through the process. Full Week The least complex program is the full week MON TO SUN” program, wherein the events for every day of the week are the same. This requires one time through the event programming process. Work WeekNext in complexity to the full week program is the work week program wherein the events are set for a typical work week (MON TO FRI) and different events are set for the weekend (SAT TO SUN). This requires two times through the events. Day by day most complex because this requires going through the programming process 7 times.

Schedule Screen Programming


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Days & Events Programming process Action Display shows…

  1. Press the SCHEDULE tab SCHEDULE screen
  2. side of the screen; EDIT changes to CANCEL
  3. Press NEXT to highlight the desired grouping of days Days change to match the selected group, e.g. MON TUE WED THU FRI
  4. Press an event: WAKE (default), LEAVE, RETURN, & SLEEP to select for programming Filled triangle above event indicates which event is selected
    for change
  5.  Press the UP/DOWN arrows to select the desired temperature After the change is made, SAVE appears in the bottom right hand of the screen
  6. Press FAN repeatedly to select desired fan mode Fan indicator displays selection (ON, AUTO, or CIRC)
  7. Press the UP/DOWN arrows to adjust the start time for the selected event Information area displays the start time
  8.  Repeat steps 4 − 7 for all remaining events. (If you selected other than MON TUE WED THU FRI SAT SUN), continue; otherwise, skip stepping 11.
  9. Press NEXT for the next group or the next day Days change to match the selected group, e.g. SAT SUN
  10. Repeat steps 3 through 8 for the remaining days, if necessary.
  11. Press SAVE when all events and days are programmed as desired The changes are made and the schedule screen reappears.

Options ScreenReminders & User Settings
CLEAN button [OPTIONS TAB > [CLEAN] ] When you select the OPTIONS tab, two buttons appear near the bottom of the screen labeled CLEAN and ENTER. Press the CLEAN button to deactivate the touch” zones for 30 seconds. Clean the screen with a soft cloth ad a mild glass cleaning solution. The Options screen provides user and installer access to the various features for setup and access to the reminders


Set timers from 1 to 24 months in either calendar time or system run time. Reminders appear when it is time to service the following (for more details on REMINDERS, see Page 15):





Press the OPTIONS tab; use the arrows to select USER SETTINGS. Press ENTER



The following items are available for modification. Follow the instructions for each parameter. DATE/TIMESet the month, day, year, hour, and minute using the DATE/ TIME option. Select DATE/TIME; press ENTER. A small, filled up-arrow indicates the selected column; use up/down arrows to adjust; press the box
below each small up-arrow to select each column. Adjust; press SAVE.


12 OR 24 HOUR clockdefault is 12H; to change, scroll to 12 OR 24HOUR; press ENTER. Use arrows to change to 24H; press SAVE.


Lennox-CS7000-Touch-Screen-Programmable-Thermostat-User-Guide-fig-16Options tab User Settings (continued)

EVENTS DAILY 2 OR 4 default is 4; to change, scroll to EVENTS DAILY 2 OR 4; press ENTER. Use arrows to change to 2; press SAVE.


VIEW CONTACT INFO scroll to VIEW CONTACT INFO from the user settings menu; press ENTER. Use BACK to return to the menu. (To set this to display on the home screen, see DISPLAY INFO.)

DISPLAY INFcontrols what is displayed in the field below the temperature and above the time on the HOME screen; it may display OUTDOOR TEMP, INDOOR RH (relative humidity), and CONTACT INFO or any combination of the three, or none if all three are set to OFF. Scroll to DISPLAY INFO; press ENTER. Use arrows to select OUTDOOR TEMP. INDOOR RH or CONTACT INFO; press ENTER.


NOTE − When turning ON the OUTDOOR TEMP option OUTDOOR SENSOR REQUIRED” will display if the physical sensor is not installed.

NOTE − If the outdoor sensor is not present and if the user tries to select the options DISPLAY INFO −> OUTDOOR TEMP or HUMIDITROL a message
is displayed OUTDOOR SENSOR REQUIRED” instead of scroll options for these menus. Information about installing the sensor is described on Page 15. For INDOOR RH, use arrows to select ON or OFF; then press SAVE.


For OUTDOOR TEMP, select ON or OFF; then press SAVE.


FAN CIRCULATE As an option to run the fan all the time, fan circulation allows the user to decide how much the fan will run during periods of equipment inactivity. The fan ON time is always set to 5 minutes. This option will cause the fan to come on more or less frequently. The default is 35%; to change, scroll to FAN CIRCULATE; press ENTER. Use arrows to change to 15, 25, or 45%; press SAVE.


  • 15% (9 minutes fan run time per hour)
  • 25% (15 minutes fan run time per hour)
  • 35% (21 minutes fan run time per hour)
  • 45% (27 minutes fan run time per hour).

Options tab User Settings (continued)
COOLING LIMITThis limits the temperature at which the thermostat may be set for cooling (default is 50º); to change to any degree between 45ºF and 90ºF, scroll to COOLING LIMIT; press ENTER. Use arrows to change to the desired temperature; press SAVE.

Title Lennox-CS7000-Touch-Screen-Programmable-Thermostat-User-Guide-fig-23 Caption Description File URL: https://thermostat.guide/wp-content/uploads/2023/01/Lennox-CS7000-Touch-Screen-Programmable-Thermostat-User-Guide-fig-23.png Copy URL to clipboard ATTACHMENT DISPLAY SETTINGS Alignment Center Link To None Size Full Size – 376 × 68 Selected media actions 46 items selected Edit SelectionClear Insert into post

This limits the temperature at which the thermostat may be set for heating (default is 85º); to change to any degree between 45ºF and 90ºF, scroll to HEATING LIMIT; press ENTER. Use arrows to change to the desired temperature; press SAVE


HUMIDITY SETTINGSee separate sections − Humidify (Page 12) and Dehumidify (Page 13).

HUMIDITROL ADJUSTIf Humiditrol® is enabled in the installer settings, then this adjustment affects the overcooling operation. Overcooling ranges from 2ºF below the cooling setpoint (MIN setting) down to 2ºF above the heating setpoint (MAX setting). Halfway between the two settings is the MID setting. The default setting is MAX; to change to MID or MIN, scroll to HUMIDITROL ADJUST; press ENTER. Use arrows to scroll to MID or MIN; then press SAVE


NOTE − Humiditrol® does not function if the outdoor temperature is 95ºF or greater nor when the indoor temperature is 65ºF or less.

BACKLIGHT SETTING default is POWER SAVE; scroll to BACKLIGHT SETTING; press ENTER. Use arrows to change to CONTINUOUS; press SAVE


BACKLIGHT INTENSITY default is 100%; scroll to BACKLIGHT INTENSITY; press ENTER. Use arrows to change from 20 to 100% in 20% increments; press SAVE


SECURITY LOCK default − no locks at all − this provides two methods of locking the thermostat: Answer YES to ALLOW TEMP ADJUST anyone can make temperature setpoint changes without entering a 3−digit code. Answer NO to ALLOW TEMP ADJUSTprevents making any changes at all until the 3−digit code is entered. Scroll to SECURITY LOCK and press ENTER; ALLOW TEMP ADJUST the screen appears; press the box below YES or NO.


The ENTER LOCK CODE screen appears.


To enter the lock code, press the box below each small up-arrow to select each column. Use up/down arrows to enter a number, then press the box below the next number and repeat to enter a 3-digit lock code; write down the number for future reference; press SAVE.
NOTE − If the security code is forgotten or misplaced, use the universal code 864″ to unlock.


if set up by the installer settings for BASIC or PRECISION, this adjustment controls the relative humidity (RH) between 15 and 45%. Scroll to HUMIDITY SETTINGS; press ENTER. Press the box below HUMIDIFY


Use up/down arrows to change the humidity setpoint (between 15 and 45%); press SAVE.


DEWPOINT if set up by the installer settings for DEWPOINT, this adjustment (only when in heating mode) will change the humidification setpoint based on the outdoor temperature and a user−defined dew point adjustment setting. When humidifying, if condensation forms on the windows, the dewpoint should be adjusted in the range of −15 to −5%; if the home feels dry, set the dewpoint upward in the range of +5 to +15%.

Scroll to HUMIDITY SETTINGS; press ENTER. Press the box below HUMIDIFY.

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Use up/down arrows to change the dewpoint (between +15 and −15%); press SAVE


NOTE − Dewpoint adj is available only when the outdoor sensor is attached. if OFF is selected in installer settings for both humidify and dehumidify,
this message appears when HUMIDITY SETTING is pressed:


If OFF is selected by the installer settings for HUMIDIFY but DEHUMIDIFY is on, the dehumidification menu appears (this setpoint adjust has NO effect on humidification):



If your system is set up to control dehumidification, this adjustment controls the relative humidity (RH) between 45 and 60%. Scroll to HUMIDITY SETTINGS; press ENTER. Press the box below DEHUMIDIFYLennox-CS7000-Touch-Screen-Programmable-Thermostat-User-Guide-fig-40

Use up/down arrows to change the humidity setpoint (between 45 and 60%); press SAVE



OFF If your system is set up for neither humidifying or dehumidifying the air, this message appears when HUMIDITY SETTING is pressed:


If your system is set up for humidifying but not dehumidifying, the humidification menu appears when HUMIDITY SETTING is pressed (this setpoint adjust has NO effect on dehumidification):



Humiditrol® Enhanced Dehumidification Accessory (EDA)
If your system includes a Humiditrol® Enhanced Dehumidification Accessory if an outdoor sensor is installed, and if Humiditrol mode is selected in the installer settings, the following setting is available: Scroll to HUMIDITY SETTINGS in user settings to confirm that you can control the DEHUMIDIFY setting.
HUMIDITROL ADJUST is available in the user settings. The default setting is MAX dehumidification but can be changed to MID or MIN. Use arrows to scroll to MID or MIN; then press SAVE.


Temporary Temperature Change Pause the Schedule

Two types of temperature changes may be made: temporary (while in the SCHEDule ON mode) or permanent (while in SCHEDule OFF).
NOTE − If autochangeover is enabled at the time a temperature hold is invoked, the thermostat MAY CHANGE OVER from heating to cooling and vice versa, to maintain the temperature hold setpoint. The autochangeover deadband (minimum separation between the heat and cool set points) is still used to determine whether changeover occurs This applies to all of the following hold modes.

Temporary Temperature Changes (schedule ON)
While the system is running with the schedule ON, any change to the temperature settings may be made for the default time (approximately 3 hours) or for as long or short a time as you wish. Therefore, following the procedure will set a HOLD on the schedule for a few hours or for up to 45 days. Figure 6 shows a typical screen set in the AUTOchangeover mode. If the SYSTEM were set in HEAT, COOL, or EM HEAT mode, only the top set of arrows appear.



  1. On the home screen, press the UP or DOWN arrow to adjust to the desired temperature.
  2.  A set of arrows appears to the right of the information display; use these arrows to adjust the hold period for as long as desired, or, if not changed, this setting will hold for approximately 3 hours.
  3.  Press SAVE.
  4. After saving, ON” next to the SCHED button flashes slowly, and the information display alternates between the following.
  5. After the 3 hours expires, the scheduled programming will resume, OR, press SCHED to cancel the hold.

Permanent Temperature Changes (schedule OFF − non−programmable operation)

To make a change for an undefined time span, the schedule must be turned OFF. The setpoint is maintained indefinitely.

  1. From the home screen, press SCHED to turn on the scheduled programming OFF.
  2.  Press the UP or DOWN arrow to set the temperature to the desired temperature.

The information display field continues to display the active mode, outdoor temperature, and indoor relative humidity. Turning the schedule back ON (press the SCHED box on the home screen) will cancel a permanent hold and return to the event-programmed mode.




Optional Remote Outdoor Sensor

The outdoor sensor (X2658) may be required, especially when using Humiditrol® EDA applications. In addition to measuring and displaying outdoor temperature, the outdoor sensor provides dew point adjustment and control for all models. If used with this thermostat, the sensor enables optimal heating equipment operation via programmable balance points. The screen will display NO OUTDOOR SENSOR until the outdoor sensor is installed, and the feature is turned on in the USER SETTINGS, in the DISPLAY INFO option. The outdoor temperature is displayed in the information display (lower center of the screen).

NOTE − For proper operation of Humiditrol® EDA applications, the outdoor sensor MUST be installed. In many applications, the ComfortSense® Model L7742U thermostat displays the temperature sensed by the remote outdoor sensor. With the heat pump system, the remote outdoor sensor helps determine when to turn on the second stage of heating for optimal comfort. When the outdoor sensor is connected, the temperature displays in the information display area (below the indoor temperature display).

Memory Protection
The thermostat stores all the information concerning its programming (state, mode, program information, last temperature measured) in nonvolatile memory. This function avoids the loss of the state of the thermostat when a power-down occurs. The only thing that might be lost is the clock, however, a lithium battery will remember clock information for as long as it has a charge (approximately 30 days). When a power down occurs (due to a power outage) the thermostat is able to switch off all relays. The O and B relay will maintain their last state.

Service Reminders

The user may turn on and turn off the following service reminders (all of which default to OFF) in either chronological time and/or run time and maybe reset (to default) or delayed (snooze) at any time:

  • Replace Media Filter
  • Routine Sys (System) Check−up
  • Replace Hum (Humidifier) Pad
  • Replace UV Lamp
  • PureAir Maintenance

NOTE − When chronological time is selected, the timer runs based on the calendar. When time is selected in run time, the timer runs based on the time the specific output is ON (e.g. Fan output for Media Filter). When the reminder time (either calendar time or run time) has elapsed, the system displays a screen from which the user can either RESET or DELAY the reminder. The user can reset the timer either before it has expired (i.e. reminder is set to 6 months and the user decides to reset it to 6 months or change it to a different value at the end of the 4th month) or when the time has expired and a reminder message has been displayed. When a reminder is turned off, the indicator will not be activated even if the timer is expired. Note that setting the filter reminder to 0 (OFF) will not reset the timers, but will deactivate the filter indicator In the case of a power interruption: the lithium battery has charged total accumulated time is maintained (i.e. the counter does not recycle to zero). lithium battery has NO change the due date of reminders is maintained.


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