Lennox l7742u Thermostat User Manual

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HOMEOWNER’S MANUAL  
ComfortSense® 7000 Series  
Model L7742U Touch Screen Programmable Thermostat  
E2009 Lennox Industries Inc.  
Dallas, Texas, USA  
CONTROLS  
506229−01  
05/09  
Litho U.S.A.  
Supersedes 04/09  
Table of Contents  
®
ComfortSense 7000 Series Model L7742U Thermostat . . .  
Display Fields & Touch Screen Points . . . . . . . . . . . . . . . . . .  
Home ScreenꢀCurrent Conditions & Temperature Settings  
Controlling the Heat/Cool Modes of Operation . . . . . . . . . . .  
Controlling the Fan Operation . . . . . . . . . . . . . . . . . . . . . . . . .  
Controlling the Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  
Schedule ScreenꢀProgramming . . . . . . . . . . . . . . . . . . . . . .  
Options screenꢀReminders & User Settings . . . . . . . . . . . .  
S Tabbed user interface with  
S Humidification measurement  
touch screen interaction  
and control  
®
S Soft blue backlighted screen S Programmable or  
Humiditrol EDA Accessory . . . . . . . . . . . . . . . . . . . . . . . . . .  
with adjustable brightness  
non−programmable options  
Temporary Temperature ChangeꢀPause the Schedule . . .  
Remote Outdoor Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  
S Equipment maintenance  
S Automatically changes  
reminders  
between heating cooling  
05/09  
506229−01  
*2P0509*  
*P506229-01*  
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®
ComfortSense 7000 Series Model L7742U Thermostat  
®
The ComfortSense 7000 Series Model L7742U thermostat is an elec-  
tronic 7−day, universal, multi−stage, programmable, touch screen ther-  
mostat. It also offers enhanced capabilities including humidification /  
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Compressor short−cycle protection (5 minutes).  
Real−time clock keeps time during power failures and automati-  
cally adjusts for daylight savings time and leap year.  
®
dehumidification / dewpoint measurement and control, Humiditrol  
EDA (Enhanced Dehumidification Accessory) control, and equipment  
maintenance reminders.  
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Maintenancereminders let user know when to service or replace  
filters, humidifier pads, ultraviolet lamps, plus two user or installer  
defined custom reminders.  
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Large, clear display with soft blue backlight shows the current and  
set temperature, day/date/time, indoor relative humidity and out-  
door temperature (if optional outdoor sensor is used).  
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Program Hold options allow user to override the program sched-  
ule as desired by time and date.  
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Select individual days or groups of days to set programming.  
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Dehumidification measurement and control  
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Programmablefan offers increased performance when combined  
with whole home indoor air quality products.  
Humiditrol EDA capability  
Dew point adjustment control  
S
Outdoor temperature display (with optional outdoor sensor)  
shows current outdoor temperature.  
Menu−drivenprogramming guides user through the scheduling  
process showing only necessary information on each screen.  
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.  
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Ergonomic design.  
Smooth Setback Recovery starts system early to achieve set-  
point at start of program period.  
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Touch Screen Display  
C SCHED (schedule) − press to change between ON and OFF.  
D Displays room temperature.  
E Displays the current operation SET AT point(s). If MODE is set to  
AUTO (autochangeover), both HEAT and COOL setpoints are  
displayed.  
F Up/down arrows used for adjusting temperature up or down; if in  
AUTO (autochangeover) mode, two sets of up/down arrows ap-  
pear.  
G Informationdisplay area, displays different information depending  
on the tab selected:  
D
HOME tab: displays outdoor temperature (if outdoor sen-  
sor X2658 is installed), indoor relative humidity (RH),  
which mode is calling, hold settings information, service  
reminders.  
D
D
SCHEDULE tab: displays the event being programmed;  
OPTIONS tab: displays a scrolling list of installer- and  
user−adjustable parameters, including filter and service  
reminder periods, etc.  
H Schedule time adjustment, User/Installer Settings up/down ar-  
rows:  
Figure 1. Touchꢀscreen display  
D
D
HOME screen: not visible except when executing a HOLD  
SETTING)  
SCHEDULE and OPTION screens: used to adjust sched-  
ule and option settings.  
Press the screen anywhere − the first press turns on the backlight.  
A Selection Tabs − Press to select: HOME (normal display),  
SCHEDULE (for programming), OPTIONS (to set fan operation,  
alerts, service reminders, and other user and installer settings).  
I
Dynamic keys − not visible in 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.  
B MODE  
− press to cycle through HEAT, COOL, AUTO  
(autochangeover),OFF, EM HEAT (emergency heat).  
ComfortSenset Model L7742U Touch Screen 7−Day Programmable Thermostat  
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Home ScreenꢁCurrent Conditions & Temperature Settings  
The HOME screen (figure 2) displays indoor temperature and outdoor  
temperatureif the outdoor sensor is installed. Other system operational  
information,such as indoor relative humidity (if turned on in user set-  
tings), dehumidifying, cooling or heating, will alternately be displayed in  
the information display.  
Equipmentoperation information appears in the boxes along the left  
side of the home screen to indicate cooling or heating equipment opera-  
tion setting, and whether scheduled programming is ON or OFF. From  
these boxes, users can change the unit’s mode to HEAT, COOL, AUTO  
(autochangeover− default), EM HEAT (emergency heat for heat pump  
applicationsincluding dual fuel and HP with Electric Heat), or OFF.  
The user can also decide whether to operate the unit per the program-  
mable schedule, or in a non−programmable mode using the SCHED  
box.  
COOLING  
TUE OCT 23 1:15PM  
INFORMATION  
DISPLAY AREA  
Figure 2. Home Screen  
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Controlling the Heat/Cool Modes of Operation  
On initial power up or after an 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 less than 2 hours, it assumes the last  
mode set. Pressing MODE repeatedly scrolls  
through all the modesꢀAUTO, EM HEAT, COOL,  
HEAT, then back to OFF.  
When the faults, errors, and service information displays appear, dy-  
namic keys will appear under the second line entries, REMIND,  
CLEAR, SERVICE, or RESET. Press the box to perform the action.  
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.  
INFORMATION DISPLAY AREA  
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 fig-  
ure 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, outdoor temperature will be included in the  
displays. The table below summarizes the information messages.  
Figure 3. Selecting Mode of Operation  
Operating Information  
Information Display Area table  
Faults, Errors, and Service Information  
TEMP SENSOR ERROR, MEMORY ERROR  
CALL FOR SERVICE  
NO OUTDOOR SENSOR  
Top line: fault/error  
Bot. line: action  
Top line: fault/error  
Bot. line: action  
SET DATE/TIME  
Default DATE/TIME (MON JAN  
HEATING, COOLING, HUMIDIFYING, DEHUMIDIFYING,  
SYSTEM OFF, OUTDOOR TEMP xxF, INDOOR RH xx%,  
MON SEP 24 3:OO PM  
[First time start up msg]  
1 12:00 PM)  
Top line: operation msgs  
CALL DEALER INFO  
Bottom line: date & time  
Top line: operation msgs  
Bottom line: date & time  
[Alternating msgs during  
a held schedule]  
REPLACE: MEDIA FILTER; UV LAMP; HUM PAD; METAL INSERT  
RESET  
Top line: serv. req’d  
Bot. line: action  
Top line: serv. req’d  
Bot. line: action  
SCHEDULE ON, SCHEDULE OFF, WAIT, FAN ON, FAN CIRC  
MON SEP 24 3:OO PM  
REMIND  
ROUTINE SYS CHECK−UP  
REMIND  
NO OUTDOOR SENSOR, HUM SENSOR ERROR, HVAC ERROR DETECTED Top line: fault/error  
HOLD SETTING UNTIL  
MON SEP 24 3:OO PM  
PRESS SCHED TO  
RESUME PROGRAM  
RESET  
REMIND  
SERVICE  
Bot. line: action  
Contact  
Installing Dealer  
DEALER INFORMATION (Edited to show dealer contact informa-  
tion [2 lines])  
ComfortSenset Model L7742U Touch Screen 7−Day Programmable Thermostat  
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Controlling the Fan Operation  
Fan Modes  
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]):  
If backlight is not on continuous, press the screen  
anywhere to turn on the backlight. Press the  
OPTIONS tab to access the FAN mode control.  
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.  
Press FAN button; repeated presses scroll through  
all the modes, AUTO, ON, and CIRC (circulate).  
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AUTOꢀthe fan is following schedule.  
ONꢀthe fan is NOT following the schedule and runs continuously  
until it is changed from the OPTIONS screen.  
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CIRCꢀthe fan is following schedule and cycles during periods of  
equipment inactivity. Cycle time is dependent on user settings  
FAN CIRCULATE (Page 10).  
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.  
If FAN mode displays AUTO and ON or CIRC was selected during  
schedulingfor 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]):  
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  
Controlling the Schedule  
If backlight is not on continuous, press the screen  
anywhere to turn on the backlight.  
If OFF, the system operates as a non−programmable thermostatꢀthe  
user must make changes when desired. The autochangeover feature  
continues to operate based on the manual user inputs.  
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).  
The fan mode is displayed on the SCHEDULE screen when program-  
ming the thermostat and can be changed only during schedule editing  
(after EDIT is pressed). Fan settings in OPTIONS screen will OVER-  
RIDE the scheduled fan operation.  
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Schedule tabꢁProgramming  
If backlight is not on continuous, press the screen anywhere to turn on  
the backlight. Press the SCHEDULE tab along the top of the screen.  
current settings.  
Programmingmay be performed in groups of days or individual days,  
as follows:  
A
B
MON TO SUN − allows every day to be set the same.  
MON TO FRI (weekday programming) and  
SAT TO SUN (weekend programming).  
EVENTS DAILY 2 OR 4ꢁThe 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".  
C
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  
repeatedlyto scroll to the desired grouping.  
Programming Complexity  
The programming process for groups of days or individual days is the  
same, except in the amount of times required to go through the process.  
Full WeekꢀThe 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.  
WAKE PERIOD BEGINS  
5:OOAM  
Work WeekꢀNext 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 DayꢀMost complex because this requires going through the  
programming process 7 times.  
Figure 4. Schedule Screen  
ComfortSenset Model L7742U Touch Screen 7−Day Programmable Thermostat  
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Schedule ScreenꢁProgramming  
Days & Events Programming process  
Action  
Display shows...  
1
2
Press SCHEDULE tab  
Press EDIT  
SCHEDULE screen  
UP/DOWN arrows on right−hand  
side of screen; EDIT changes to  
CANCEL  
3
4
Press NEXT to highlight the de-  
sired grouping of days  
Days change to match selected  
group, e.g. MON TUE WED THU FRI  
Press an event: WAKE (default),  
LEAVE, RETURN, & SLEEP to  
select for programming  
Filled triangle above event  
indicates which event is selected  
for change  
WAKE PERIOD BEGINS  
5:OOAM  
5
Press UP/DOWN arrows to  
select desired temperature  
After change is made, SAVE  
appears in the bottom right−hand  
of the screen  
9
11  
6
7
Press FAN repeatedly to select  
desired fan mode  
Fan indicator displays selection  
(ON, AUTO, or CIRC)  
Press UP/DOWN arrows to  
adjust start time for  
selected event  
Information area displays start  
time  
Figure 5. Programming days and events  
8
(If you selected other than MON TUE WED THU FRI SAT SUN), continue;  
9
Press NEXT for the next group  
or the next day  
Days change to match selected  
group, e.g. SAT SUN  
11 Press SAVE when all events and The changes are made and the  
days are programmed as desired schedule screen reappears.  
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Options ScreenꢁReminders & User Settings  
CLEAN button [OPTIONS TAB > [CLEAN] ]  
User Settings [OPTIONS TAB > USER SETTINGS > [ENTER] ]  
When you select the OPTIONS tab, two buttons appear near the bot-  
tom of the screen labeled CLEAN and ENTER. Press the CLEAN but-  
ton to deactivate the ꢁtouch" zones for 30 seconds. Clean the screen  
with a soft cloth and a mild glass cleaning solution.  
12 OR 24 HOUR  
F/C  
BACKLIGHT INTENSITY  
BACKLIGHT SETTING  
COOLING LIMIT  
DATE/TIME  
DISPLAY INFO  
EVENTS DAILY 2 OR 4  
FAN CIRCULATE  
HEATING LIMIT  
HUMIDITROL ADJUST  
HUMIDITY SETTING Pages 11, 12, 13  
SECURITY LOCK  
VIEW CONTACT INFO  
The Options screen provides user and installer access to the various  
features for setup and access to the reminders.  
Press the OPTIONS tab; use the arrows to select USER SETTINGS.  
Press ENTER.  
USER SETTINGS  
INSTALLER SETTINGS  
The following items are available for modifying. Follow the instructions  
for each parameter.  
REMINDERS  
USER SETTINGS  
DATE/TIMEꢀSet month, day, year, hour, and minute using DATE/  
TIME option. Select DATE/TIME; press ENTER. Small, filled up-arrow  
indicates selected column; use up/down arrows to adjust; press box  
below each small up-arrow to select each column. Adjust; press SAVE.  
FEB 11 2OO8 12PM 49  
HR MIN  
MON DAY YR  
Reminders [OPTIONS TAB > REMINDERS > [ENTER] ]  
CANCEL  
|
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| SAVE|  
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  
F/Cꢀdefault is Fahrenheit; to change to Celsius, scroll to F/C; press  
ENTER. Use arrows to change to C; press SAVE.  
F OR C  
DEFAULT(F)  
REPLACE MEDIA FILTER  
DUE FRI JUN 12 O9  
REPLACE UV LAMP  
DUE FRI SEP 11 O9  
F
12 OR 24 HOUR clockꢀdefault is 12H; to change, scroll to 12 OR 24  
HOUR; press ENTER. Use arrows to change to 24H; press SAVE.  
12 OR 24 HOUR  
ROUTINE SYS CHECK−UP  
DUE IN 216O HOURS  
PURE AIR MAINTENANCE  
DUE FRI SEP 11 O9  
REPLACE HUM PAD  
DUE FRI JUN 12 O9  
(CUSTOM REMINDER 1)  
DUE WED OCT 21 09  
DEFAULT(12HR)  
12H  
ComfortSenset Model L7742U Touch Screen 7−Day Programmable Thermostat  
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Options tabꢁUser Settings (continued)  
EVENTS DAILY 2 OR 4ꢀdefault is 4; to change, scroll to EVENTS  
DAILY 2 OR 4; press ENTER. Use arrows to change to 2; press SAVE.  
For INDOOR RH, use arrows to select ON or OFF; then press SAVE.  
INDOOR RH  
DEFAULT(OFF)  
EVENTS DAILY 2 OR 4  
DEFAULT(4)  
ON  
2
VIEW CONTACT INFOꢀscroll to VIEW CONTACT INFO from the  
user settings menu; press ENTER. Use BACK to return to menu. (To  
set this to display on the home screen, see DISPLAY INFO.)  
For OUTDOOR TEMP, select ON or OFF; then press SAVE.  
OUTDOOR TEMP  
DEFAULT(OFF)  
ON  
DISPLAY INFOꢀcontrols what is displayed in the field below the tem-  
peratureand above the time on the HOME screen; it may display OUT-  
DOOR TEMP, INDOOR RH (relative humidity), and CONTACT INFO  
or any combination of the three, or none if all three are set to OFF.  
For CONTACT INFO, select ON or OFF; then press SAVE.  
CONTACT INFO  
DEFAULT(OFF)  
ON  
Scroll to DISPLAY INFO; press ENTER. Use arrows to select OUT-  
DOOR TEMP. INDOOR RH or CONTACT INFO; press ENTER.  
FAN CIRCULATEꢀAs an option to running the fan all the time, fan cir-  
culate allows the user to decide how much the fan will run during peri-  
ods 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.  
DISPLAY INFO  
OUTDOOR TEMP  
INDOOR RH  
CONTACT INFO  
NOTE − When turning ON the OUTDOOR TEMP option ꢀOUT-  
DOOR SENSOR REQUIRED" will display if the physical sensor  
is not installed.  
FAN CIRCULATE  
DEFAULT(35%)  
25%  
NOTE − If outdoor sensor is not present and if user tries to select the  
options DISPLAY INFO −> OUTDOOR TEMP or HUMIDITROL a mes-  
sage is displayed ꢀOUTDOOR SENSOR REQUIRED" instead of scroll  
options for these menus. Information about installing the sensor is de-  
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).  
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Options tabꢁUser Settings (continued)  
COOLING LIMITꢀThis 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 desired temperature; press SAVE.  
BACKLIGHT INTENSITYꢀdefault is 100%; scroll to BACKLIGHT IN-  
TENSITY; press ENTER. Use arrows to change to 20 to 100% in 20%  
increments;press SAVE.  
BACKLIGHT INTENSITY  
DEFAULT(1OO%)  
8O%  
COOLING LIMIT  
DEFAULT(5O°F)  
55°F  
SECURITY LOCKꢀdefault − no locks at all − this provides two methods  
of locking the thermostat:  
HEATING LIMITꢀThis 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 desired temperature; press SAVE.  
Answer YES to ALLOW TEMP ADJUSTꢀanyone can make tem-  
perature setpoint changes without entering a 3−digit code.  
Answer NO to ALLOW TEMP ADJUSTꢀprevents making any  
changes at all until the 3−digit code is entered.  
HEATING LIMIT  
DEFAULT(85°F)  
80°F  
Scroll to SECURITY LOCK and press ENTER; ALLOW TEMP AD-  
JUST screen appears; press box below YES or NO.  
HUMIDITY SETTINGꢀSee separate sections − Humidify (Page 12)  
ALLOW TEMP ADJUST  
YES  
®
HUMIDITROL ADJUSTꢀIf Humiditrol is enabled in the installer set-  
NO  
tings, then this adjustment affects 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.  
CANCEL  
|
|
|
The ENTER LOCK CODE screen appears.  
ENTER LOCK CODE  
O
O
O
HUMIDITROL ADJUST  
DEFAULT (MAX)  
CANCEL  
MIN  
|
|
|
|
SAVE|  
®
NOTE − Humiditrol does not function if the outdoor temperature is 95ºF  
or greater nor when the indoor temperature is 65ºF or less.  
To enter the lock code, press 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.  
BACKLIGHT SETTINGꢀdefault is POWER SAVE; scroll to BACK-  
LIGHT SETTING; press ENTER. Use arrows to change to CONTINU-  
OUS; press SAVE.  
NOTE − If the security code is forgotten or misplaced, use the universal  
code ꢀ864" to unlock.  
BACKLIGHT SETTING  
DEF(SAVE)  
POWER SAVE  
ComfortSenset Model L7742U Touch Screen 7−Day Programmable Thermostat  
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Humidification  
BASIC & PRECISIONꢀif set up by the installer settings for BASIC or  
PRECISION, this adjustment controls the relative humidity (RH) be-  
tween 15 and 45%.  
Scroll to HUMIDITY SETTINGS; press ENTER. Press the box below  
HUMIDIFY.  
HUMIDITY MODE  
HUMIDIFY  
DEHUMIDIFY  
Scroll to HUMIDITY SETTINGS; press ENTER. Press the box below  
HUMIDIFY.  
|
|
HUMIDITY MODE  
Use up/down arrows to change the dewpoint (between +15 and −15%);  
press SAVE.  
HUMIDIFY  
DEHUMIDIFY  
|
|
DEW POINT ADJ  
DEFAULT (O%)  
−5%  
Use up/down arrows to change the humidity setpoint (between 15 and  
45%); press SAVE.  
NOTE − Dewpoint adj available only when outdoor sensor is attached.  
HUM SETPOINT  
DEFAULT (45%)  
4O%  
OFFꢀif OFF selected in installer settings for both humidify and dehu-  
midify, this message appears when HUMIDITY SETTING is pressed:  
HUMIDITY MODES OFF  
DEWPOINTꢀif set up by the installer settings for DEWPOINT, this ad-  
justment (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 dewpoint upward in the range of +5 to  
+15%.  
If OFF is selected by the installer settings for HUMIDIFY but DE-  
HUMIDIFY is on, the dehumidification menu appears (this setpoint ad-  
just has NO effect on humidification):  
DEHUM SETPOINT  
DEFAULT (5O%)  
45%  
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Dehumidification  
®
If your system is set up to control dehumidification, this adjustment con-  
trols the relative humidity (RH) between 45 and 60%. Scroll to HUMID-  
ITY SETTINGS; press ENTER. Press the box below DEHUMIDIFY.  
HUMIDITY MODE  
Humiditrol Enhanced Dehumidification  
Accessory (EDA)  
®
If your system includes a Humiditrol Enhanced Dehumidification Ac-  
cessory, if an outdoor sensor is installed, and if Humiditrol mode is se-  
lected in the installer settings, the following setting is available:  
HUMIDIFY  
DEHUMIDIFY  
|
|
Use up/down arrows to change the humidity setpoint (between 45 and  
60%); press SAVE.  
Scroll to HUMIDITY SETTINGS in user settings to confirm that you can  
control the DEHUMIDIFY setting.  
DEHUM SETPOINT  
DEFAULT(5O%)  
45%  
HUMIDITY MODE  
HUMIDIFY  
DEHUMIDIFY  
OFFꢀIf your system is set up for neither humidifying or dehumidifying  
the air, this message appears when HUMIDITY SETTING is pressed:  
HUMIDITY MODES OFF  
|
|
HUMIDITROL ADJUST is available in the user settings. The default  
settingis MAX dehumidification but can be changed to MID or MIN. Use  
arrows to scroll to MID or MIN; then press SAVE.  
If your system is set up for humidifying but not dehumidifying, the hu-  
midificationmenu appears when HUMIDITY SETTING is pressed (this  
setpoint adjust has NO effect on dehumidification):  
HUM SETPOINT  
HUMIDITROL ADJUST  
DEFAULT (MAX)  
DEFAULT(45%)  
45%  
MIN  
ComfortSenset Model L7742U Touch Screen 7−Day Programmable Thermostat  
Page 13  
 
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Temporary Temperature ChangeꢁPause the Schedule  
Two types of temperature changes may be made: temporary (while in  
the SCHEDule ON mode) or permanent (while in SCHEDule OFF).  
5. After the 3 hours expires, the scheduled programming will re-  
sume, OR, press SCHED to cancel the hold.  
Permanent Temperature Changes (schedule OFF − non−  
programmable operation)  
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 auto-  
changeover 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.  
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 the scheduled pro-  
grammingOFF.  
Temporary Temperature Changes (schedule ON)  
2. Press the UP or DOWN arrow to set the temperature to the  
desired temperature.  
While the system is running with the schedule ON, any change to the  
temperaturesettings may be made for the default time (approximately 3  
hours) or for as long or short a time as you wish. Therefore, following the  
procedurewill set a HOLD on the schedule for a few hours or for up to  
mode. If the SYSTEM were set in HEAT, COOL, or EM HEAT mode,  
only the top set of arrows appear.  
The information display field continues to display the active mode, out-  
door temperature, indoor relative humidity. Turning the schedule back  
ON (press SCHED box on home screen) will cancel a permanent hold  
and return to the event-programmed mode.  
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:  
HOLD SETTING UNTIL  
10:49AM  
OCT 10  
HOLD SETTING UNTIL  
WKD MMM DD HH:MMMM  
and  
PRESS SCHED TO  
RESUME PROGRAM  
Figure 6. Setting a Hold on the Schedule  
Page 14  
506229−01 05/09  
 
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Optional Remote Outdoor Sensor  
Service Reminders  
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 adjust-  
ment and control for all models. If used with this thermostat, the sensor  
enables optimal heating equipment operation via programmable bal-  
ance points. The screen will display NO OUTDOOR SENSOR until the  
outdoor sensor is installed, the feature is turned on in the USER SET-  
TINGS, in the DISPLAY INFO option. The outdoor temperature is dis-  
played in the information display (lower center of the screen).  
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  
may be reset (to default) or delayed (snooze) at any time:  
Replace Media Filter  
Routine Sys (System) Check−up  
Replace Hum (Humidifier) Pad  
Replace UV Lamp  
PureAirt Maintenance  
NOTE − For proper operation of Humiditrol® EDA applications, the  
outdoor sensor MUST be installed.  
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).  
®
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 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.  
When the outdoor sensor is connected, the temperature displays in the  
informationdisplay area (below the indoor temperature display).  
The user can reset the timer either before it has expired (i.e. reminder is  
set to 6 months and user decides to reset it to 6 months or change it to  
different value at the end of 4th month) or when the time has expired and  
a reminder message has been displayed.  
Memory Protection  
The thermostat stores all the information concerning its programming  
(state, mode, program information, last temperature measured) in a  
nonvolatilememory.  
When a reminder is turned off, the indicator will not be activated even if  
the timer is expired. Note that setting filter reminder to 0 (OFF) will not  
reset the timers, but will deactivate the filter indicator.  
This function avoids the loss of the state of the thermostat when a pow-  
er−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  
charge (approximately 30 days). When 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.  
In the case of a power interruption:  
S
S
lithium battery has chargeꢀthe total accumulated time is main-  
tained (i.e. the counter does not recycle to zero).  
lithium battery has NO chargeꢀthe due date of reminders is main-  
tained.  
ComfortSenset Model L7742U Touch Screen 7−Day Programmable Thermostat  
Page 15  
 

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