OPERATION MANUAL
E2008 Lennox Industries Inc.
Dallas, Texas, USA
RETAIN THESE INSTRUCTIONS
FOR FUTURE REFERENCE
L3711C 7−Day Programmable Thermostat
The Lennox ComfortSenset 3000 Series model L3711C
7-day programmable electronic thermostat provides
excellent temperature control and has a large,
easy-to-read display. This product includes a
programmable filter change reminder, an equipment
maintenance reminder, and a system check indicator to
notify the user when the equipment requires service.
Thermostat model L3711C is suitable for non−heat pump,
single-stage heat/single-stage cool applications with either
gas or electric furnace. Also, the thermostat provides autochangeover capability.
ComfortSenset 3000 Series
Model No. L3711C 7-Day
Programmable Thermostat
CONTROLS
506072−01
02/08
Supersedes 505,067M
Table of Contents
7−Day Programmable Thermostats 1. . . . . . . . . . . . . . .
General 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Introduction 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Initial Thermostat Power-up 1. . . . . . . . . . . . . . . . . . . . .
Buttons, Backlight, Timers & Settings 2. . . . . . . . . . . .
DAY/TIME − Set Day and Time 2. . . . . . . . . . . . . . . . . .
HEAT − Heat Mode 3. . . . . . . . . . . . . . . . . . . . . . . . . . . .
COOL − Cool Mode 3. . . . . . . . . . . . . . . . . . . . . . . . . . . .
AUTO − Using the Autochangeover Mode 3. . . . . . . . .
HOLD − Temperature Hold Mode 4. . . . . . . . . . . . . . . .
PROG − Thermostat Programming 4. . . . . . . . . . . . . . .
COPY − Copy a Program 5. . . . . . . . . . . . . . . . . . . . . . .
FAN − Controlling Fan Operation 5. . . . . . . . . . . . . . . . .
Displaying Outside Temperature 5. . . . . . . . . . . . . . . . .
SETTINGS − Filter /Maintenance Reminder 5. . . . . . .
Service Indicator 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thermostat RESET 6. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Removing/Installing Thermostat 6. . . . . . . . . . . . . . . . .
Default Thermostat Settings 6. . . . . . . . . . . . . . . . . . . .
Thermostat Output Table 7. . . . . . . . . . . . . . . . . . . . . . .
Technical Specifications 7. . . . . . . . . . . . . . . . . . . . . . . .
Litho U.S.A.
General
These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
having jurisdiction before installation.
Check equipment for shipping damage. If you find any
damage, immediately contact the last carrier.
Introduction
This document describes the operation of Lennox model
L3711C thermostat. Refer to the installation manual for instructions regarding installation and wiring of the thermostat.
Initial Thermostat Power-up
When power is initially applied to the thermostat, the display will appear as shown in figure 1.
Copy tofrom
PROG
A B C D
HOLD
FAN ON
AUTO
FILTER
MAINTENANCE
OUTROOM
i88
Figure 1. Initial Power−Up Display
All display segments are momentarily activated. This occurs as a normal part of thermostat initialization.
MO TU WE TH FR SA SU
AM
I8:88
PM
COOL SETPOINT
SERVICE
88
HEAT SETPOINT
°
88
°
COOL
OFF
AUTO
EMG.
HEAT
°
Hi
Lo
02/08 506072−01
*2P0208* *P506072-01*
Within a few seconds, the HOME screen appears (see figure 2) with default settings as shown. After about 1 minute
of initialization time, the actual room temperature will be
displayed.
PROG
A B C D
HOLD
FAN ON
AUTO
MO
AM
PM
ROOM
I0:26
COOL
AUTO
°
EMG.
HEAT
OFF
70
Figure 2. Home Screen
At this point, the thermostat will be fully functional; its default temperature setpoint (not shown) is 70°F. At this
point, if the equipment has been fully powered and if a heat
demand were present, the system would begin operating.
NOTE − Temperature scale default is Fahrenheit units but
may be reset to show Celsius, if desired. See page 7.
Buttons, Backlight, Timers & Settings
Buttons are located behind the small door on the right−
hand side of the thermostat (see figure 3).
IMPORTANT
Do NOT begin pressing buttons until after you read
the following section describing each button.
A pale blue display backlight illuminates for 30 seconds
each time any button is pressed.
When the PROG or DAY/TIME button is pressed, a field
begins flashing, expecting another input. Start making
changes within 15 seconds or the HOME screen will return.
Heat
Cool
Prog
Auto
Day/Time
Copy
(DOOR
Fan
Settings
Hold
Enter
(Outside)
OPEN)
Figure 3. Thermostat Buttons
When an Arrow, HOLD, HEAT, or COOL button is pressed,
SETPOINT and the temperature setting appears for 15
seconds. If desired, start making changes within 15 seconds or the HOME screen will return. The backlight will
turn off 15 seconds after the HOME screen reappears.
DAY/TIME − Setting the Day and Time
Press the DAY/TIME button and set the CURRENT hour,
minute, and day of week as follows:
1. AM12" will flash on the screen. Press the UP/DOWN
arrows to change the hour. (AM" or PM" must correspond to time of day.) Press the DAY/TIME button OR,
if adjusting for daylight savings time, pressing the ENTER button stores the single change and exits to the
HOME screen, bypassing minutes and day of week.
2. Minutes will flash. Use the UP/DOWN arrow button to
display the minutes past the hour. Press the DAY/
TIME button.
3. Day MO" (Monday) will flash. Use UP or DOWN arrow
buttons to display the current day. Day selections are
abbreviated as MO, TU", WE", TH", FR", SA",
and SU". Press the DAY/TIME button.
4. The HOME screen reappears; confirm day and time
are correct. This completes day and time setting.
506072−01 02/08
Page 2
HEAT − Using the Heat Mode
COOL − Using the Cool Mode
Enabling and Disabling Heat Mode
The thermostat must be in the heat mode to control the
heating equipment. Press the HEAT button to enable or
disable heat mode. If the thermostat is in cool or off mode,
pressing the HEAT button enables the heat mode (indicated by HEAT in the lower right corner − see figure 4).
Heat
Cool
Prog
Auto
5:30
Day/Time
Copy
82
(DOOR
°
°
OPEN)
OFF
HEAT
Fan
Settings
Hold
Enter
(Outside)
70
66
Figure 4. Turn Heat ON/OFF
If the thermostat is in heat mode, heat mode is disabled
when the HEAT button is pressed. This is indicated by OFF
near the right side of the display as shown in figure 5.
ROOM
75
°
HEAT SETPOINT
75
Figure 5. Heat/Cool Mode Disabled
Heating Demand
Set the thermostat to heat mode to control the heating
equipment. Then, if the room temperature is lower than the
temperature setpoint, as shown in figure 6, the thermostat
detects a heating demand and will activate the heating
equipment to satisfy the demand.
ROOM
72
°
HEAT SETPOINT
75
Enabling and Disabling Cool Mode
Use the COOL button to enable or disable cool mode as
desired. If the thermostat is in heat or off mode, cool mode
is enabled when the COOL button is pressed. This is indicated by COOL on the right side of the display (see figure
7).
Heat
Cool
Prog
Auto
i0:30
Day/Time
Copy
70
(DOOR
Fan
Settings
Hold
Enter
(Outside)
75
66
Figure 7. Turn Cool ON/OFF
If the thermostat is in cool mode, pressing the COOL button disables cool mode (indicated by OFF, similar to figure
5).
Cooling Demand
Set the thermostat to cool mode to control the cooling
equipment. Then, if the room temperature is higher than
the temperature setpoint, as shown in figure 7, the thermostat detects a cooling demand and will activate the cooling
equipment to satisfy the demand.
Cooling operation is indicated by flashing snowflake"
icons in the display. When the actual temperature drops
below the temperature setpoint, the snowflake icons will
disappear. This indicates that the cooling demand has
been satisfied and that the cooling equipment has been
turned off.
NOTE − If no buttons are pressed during a demand for
cooling, the equipment must operate for at least 4 minutes.
After a demand has been satisfied, cooling equipment operation is locked out for 5 minutes. If another cooling demand occurs during this 5−minute interval, COOL" and the
snowflakes will flash; however, the cooling equipment will
not operate until the 5−minute delay has elapsed.
NOTE − The cooling setpoint cannot be lower than the
heating setpoint. Also, the difference between the cooling
and heating setpoint must be at least 4 degrees.
AUTO − Using the Autochangeover Mode
OPEN)
Figure 6. Heating Demand
Heating operation is indicated by a flame icon in the lower
right corner. When the actual temperature rises above the
temperature setpoint, the flame icon will disappear. This
indicates that the heating demand has been satisfied and
that the heating equipment has been turned off.
NOTE − Heating equipment is activated for at least 3 minutes if no buttons are pressed during the demand interval.
When in either heat mode or cool mode, autochangeover
can be enabled or disabled by pressing the AUTO button. If
enabled, AUTO appears at the lower right corner of the display. The thermostat will then automatically change over
from heating to cooling and vice versa, to keep the room
temperature in between the heating and cooling setpoints.
Autochangeover can be used in either of the thermostat
hold modes, or when the thermostat program is running.
These modes are described later.
Page 3
L3711C 7-DAY PROGRAMMABLE THERMOSTAT
HOLD − Using Temperature Hold Modes
When HOLD is displayed at the HOME screen, the thermostat is in a temperature hold condition. This means that
the temperature program data is ignored and the thermostat functions much like a non−programmable thermostat.
Adjusting Temperature Setpoint in Hold Mode
The temperature setpoint represents the desired temperature of the space around the thermostat. The default heat
setpoint in hold mode is 70°F; the default cool setpoint in
hold mode is 78°F.
To adjust the setpoint, press the UP or DOWN (YB) arrow
buttons (see figure 8); the existing setpoint is displayed to
the right of the actual room temperature. Each button
press adjusts the setpoint up or down by 1 degree.
Heat
Cool
Prog
Auto
i0:30
Day/Time
Copy
78
80
70
Fan
Settings
Hold
Enter
(Outside)
(DOOR
OPEN)
Heat
Cool
Prog
Auto
i0:30
Day/Time
Copy
70
Fan
Settings
Hold
Enter
(Outside)
72
68
Figure 9. Temporary Hold Temperature Mode
PROG − Thermostat Programming
The L3711C thermostat can be programmed to perform a
set of both heating and cooling events for each day of the
week. Each day can be programmed for 4 unique events
per day, and each day can be different from any other day.
To Set Program Events and Temperatures
Figure 10 gives an example of how up to 7 different programs can be set. Programs A and C reflect the desired
warmth while the home IS occupied (72°); B allows less
heating while the home is NOT occupied; D reflects a cool
sleeping temperature.
NOTE − The example in figure 10 shows heat setpoints; a
similar program may be set for cool setpoints.
MONDAY PROGRAM: 72°
TUESDAY PROGRAM: 72°
68°
64°
68°
64°
A
A
C
B
C
B
(DOOR
OPEN)
D
D
Figure 8. Hold Temperature Mode
After the desired setpoint is reached, the HOME screen
will reappear after about 15 seconds.
Permanent Hold Mode
At any time the program is running, from the HOME
screen, set a permanent hold (program override) by pressing the HOLD button (see figure 8). The thermostat now
functions much like a non−programmable thermostat. Use
the Up/Down arrow buttons to adjust the hold setpoint. To
return to the program, press HOLD again.
Temporary (2-Hour) Hold
At any time the program is running, from the HOME
screen, set a temporary 2-hour hold by pressing the Up/
Down arrow buttons until the desired setpoint is displayed;
HOLD" flashes (see figure 9). This overrides the program
for 2 hours from the last button press, then returns to the
program.
While in Temporary Hold, press HOLD once to switch to
Permanent Hold (HOLD displays solid; PROG not displayed); press HOLD again to return to the program
(PROG displays; HOLD not displayed).
WEDNESDAY PROGRAM: 72°
THURSDAY PROGRAM: 72°
FRIDAY PROGRAM: 72°
SATURDAY PROGRAM: 72°
SUNDAY PROGRAM: 72°
68°
A
64°
A
68°
64°
A
68°
64°
68°
64°
68°
64°
A
A
6AM NOON 6PM MID 6AM
C
B
C
B
C
B
C
B
C
B
NIGHT
D
D
D
D
D
Figure 10. 7-Day Program Example
NOTE − Pressing the ENTER button during the following
programming steps, saves and exits to the HOME screen.
To program events and temperatures, perform the following steps.
1. Press and release the PROG button. "MO" (Monday),
"AM 6:00", period "A", "COOL SETPOINT 78", and
"HEAT SETPOINT 70" are displayed. "AM 6" flashes.
506072−01 02/08
Page 4
2. Use the Up/Down arrow buttons to select the desired
hour; press the PROG button when the desired hour
is reached; use the Up/Down arrow buttons again to
select desired minute. The selected hour/minute is
when the program will start. Press the PROG button.
3. Use the Up/Down arrow buttons to select the desired
heat setpoint; press the PROG button.
4. Use the Up/Down arrow buttons to select the desired
cool setpoint; press the PROG button.
5. Repeat steps 1 − 4 for Monday, periods B, C, and D.
6. COPY A PROGRAM − If the program entered for
Monday is satisfactory for other days of the week, do
the following to repeat the same program for other
days:
A Press the PROG button, then press the COPY
button. The display clears the screen except for
Copy from MO with MO" flashing. Press the
COPY button again to copy Monday’s program.
B The display changes to Copy to MO". Use the ar-
row buttons to scroll to the desired day where you
want the same program as Monday. Press the
COPY button.
C Repeat steps A and B for as many days as you
want the same program.
Heat
Cool
Prog
Auto
i0:30
Day/Time
Copy
Fan
72
Hold
Figure 12. Using Fan ON
If auto fan mode is selected (AUTO displayed in FAN box −
see figure 13), the fan will only run when the heating or
cooling equipment is running.
Heat
Cool
Prog
Auto
i0:30
Day/Time
Copy
Fan
72
Figure 13. Using Fan AUTO
Displaying Outside Temperature
Hold
Heat
Cool
Copy from MO
Prog
Copy
Fan
Settings
Auto
Day/Time
Hold
Enter
(Outside)
(DOOR
OPEN)
Figure 11. Copy a Programmed Day to Another
Day
7. Repeat steps 1 − 5 to program different times and temperatures for days not yet programmed.
FAN − Controlling the Fan Operation
Use the FAN button to select either continuous fan mode or
auto fan mode.
To change from continuous to auto fan mode (or vice versa), press the FAN button. Note whether a fan icon in the
FAN box is present (indicating that the fan is running) or not
(fan not running).
If continuous fan mode is enabled (ON displayed in FAN
box − see figure 12), the fan will run continuously regardless of whether the heating or cooling equipment is running.
Pressing the ENTER (Outside) button at the HOME
screen displays the outside temperature (see figure 14) for
several seconds, then returns to room temperature.
Fan
Settings
Hold
Enter
(Outside)
88
Figure 14. Check Outside Temperature
SETTINGS − Filter/Maintenance Reminders
The L3711C thermostat is designed to remind you when
the filter needs changing or when routine maintenance is
required, as (and if) defined, by you. These optional reminders are not enabled until you activate them. To do so,
press the SETTINGS button once or twice for the desired
reminder as shown in figure 15 and as described in table 1.
OFF
For FILTER, press SETTINGS
button 1 time
FILTER
MAINTENANCE
Figure 15. Reminder Settings Display
For MAINTENANCE, press
SETTINGS button 2 times
Page 5
L3711C 7-DAY PROGRAMMABLE THERMOSTAT
The default setting for the reminders is OFF (disabled).
(1st
)
(Off, 1, 3, 6, 12); f
th
f
lf
to scroll
when to perform routine checks
Press Up/Down arrow buttons to select the desired reminder intervals.
Table 1. Filter and Maintenance Reminders
Buttons to
Use
SETTINGS
press
then Arrows
to scroll
selections
SETTINGS
(2nd press)
en Arrows
to scroll
selections
Enter Stores settings.
NOTE − The HOME screen will reappear about 15 seconds
after the final arrow button press. OR, press the ENTER
button at any time to store any changes and exit to the
HOME screen.
After either programmed interval has elapsed, the reminder will be displayed as shown in figure 16.
PROG
A B C D
HOLD
FAN ON
AUTO
FILTER SERVICE
MAINTENANCE
Reminder
MAINTE-
MO
ROOM
FILTER
NANCE
AM
I0:26
PM
°
Available Settings and
How to Use
Total fan run time expressed in
months
example, if fan runs 12 hours a
day, 1 month reminder displays
in 2 calendar months.
Elapsed chronological time in
months (Off, 6, 12). Use this,
or example, to remind yourse
when to perform routine checks
or when to call a technician for
perodic preventive
maintenance.
or
Filter &
COOL
OFF
AUTO
EMG.
HEAT
Maintenance
Indicators
76
FAN ON
AUTO
FILTER SERVICE
MAINTENANCE
ROOM
COOL
OFF
AUTO
°
EMG.
HEAT
Service
Indicator
Flashing
76
Figure 16. Reminders
After the filter has been changed or maintenance performed, reset the reminder by pressing the SETTINGS
button for 4 seconds at the corresponding reminder settings screen. The screen will blink for a few moments to indicate that the timer has been reset.
Service Indicator
When abnormal equipment operation is detected, the
SERVICE indicator will flash on the screen (see figure 16).
This indicates that the equipment requires service from a
qualified service technician.
Thermostat RESET
Under some abnormal conditions, it may be necessary to
reset" the thermostat to its default condition. Such a RESET would delete all programming and settings and therefore should only be used on rare occasions when the the
thermostat fails to function as designed and/or as programmed. Such an instance can occur as a result of a power surge or similar electrical disturbance (e.g. after an electrical storm or power outage). The RESET button can be
used to recover from this situation.
CAUTION
When the RESET button is pressed, ALL settings revert back to the defaults, including the default program (see tables 2 and 3).
The RESET button is an unlabeled, recessed button located behind the door on the right−hand side of the thermostat, below the SETTINGS button (see figure 3). Use a paper clip or small pencil to press the RESET button; ALL
thermostat settings will be reset to the defaults listed in the
Default Thermostat Settings section.
Removing/Installing Thermostat
The thermostat hinges on tabs on the top of the subbase;
no tool is needed to remove the thermostat from the subbase. Pivot the bottom of the thermostat outward (releasing the snaps), then lift up to remove.
To replace it, first position the top tilted toward the wall
bracket and align it until you feel the tabs and slots engage;
then, while the top is in place, pivot the bottom toward the
wall until the thermostat snaps into place.
Default Thermostat Settings
Default thermostat settings are in table 2 and the default
program is shown in table 3.
Table 2. Default Thermostat Settings
Mode Heat (Perm. Hold)
Heat Setpoint (Perm Hold) 70°F (or 21°C)
Cool Setpoint (Perm Hold) 78°F (or 26°C)
Fan Auto
Filter Reminder OFF
Maintenance Reminder OFF
Equipment Protection Timers Reset Back to Zero
Autochangeover OFF
Table 3. Default Program Settings −
Time & Temperature
Programs Time Temp. − Heat Temp. Cool
All days − A 6:00am 70_F / 21°C 78_F / 26°C
All days − B 8:00am 62_F / 17°C 85_F / 29°C
All days − C 6:00pm 70_F / 21°C 78_F / 26°C
All days − D 10:00pm 62_F / 17°C 82_F / 28°C
506072−01 02/08
Page 6
Thermostat Output Table
Table 4 depicts the L3711C thermostat output states for
various input conditions.
Table 4. L3711C Thermostat Outputs
Condition W1 Y1 G
Gas Heat, Auto Fan
Heat Demand X
Cool Demand X X
No Demand
Gas Heat, Continuous Fan
Heat Demand X X
Cool Demand X X
No Demand X
Electric Heat, Auto Fan
Heat Demand X X
Cool Demand X X
No Demand
Electric Heat, Continuous Fan
Heat Demand X X
Cool Demand X X
No Demand X
NOTE − X = output is activated with 24VAC.
Technical Specifications
Thermostat Type
Electronic programmable thermostat for 1-Stage
Heat/1-Stage Cool, gas or electric heat, non−heat pump,
non−power robbing applications.
Power Supply Range
18VAC − 30VAC (24VAC nominal), 60Hz
CAUTION
24VAC is present on the terminals of the thermostat
bracket. If removing the thermostat from the wall,
use caution and avoid touching any of the connector terminals on the wall bracket.
Also, when working with the thermostat dip
switches, use a non−conductive tool and take caution to avoid making any contact with the circuit
board, its imprinted circuitry and its connector
prongs.
Temperature Display
Display Scale: Fahrenheit or Celsius user selectable (via
DIP switch; see figure 17)
Display range: 35°F (2°C) to 99°F (37°C)
Display resolution: 1°F (1°C)
Display Accuracy: +/−1°F
If the Fahrenheit/Celsius display must be changed, use a
plastic, non−conductive tool to push the dip switch to the
right position (see figure 17).
1
2
3
4
5
6
7
PLUG IN (Use Care To Avoid Bending Prongs.)
F/C (Fahrenheit/Celsius) switch
shown in Celsius position
Figure 17. Changing Fahrenheit/Celsius Setting
Indoor Temperature Measurement Range
Measurement Scale: Fahrenheit
Measurement Range: 35°F to 99°F
Measurement Resolution: 0.5°F
Measurement Accuracy: +/−1°F
Field Offset: via DIP switches to +/−3°F
Sampling Method: temperature measurements sampled
every 15 seconds. Displayed temperature is the average
of the last four measurements.
Outdoor Temperature Measurement Range
Measurement Scale: Fahrenheit
Measurement Range: −22°F to 122°F
Measurement Resolution: 1°F
Measurement Accuracy: +/−2°F
Temperature Setpoint Range
Setting range: 50°F (10°C) to 90°F (32°C)
Setting resolution: 1°F (1°C)
Smart Setback Recovery (via DIP switch #6)
Smart Setback Recovery (SSR) affects the way the thermostat responds to program events. If SSR is disabled, the
thermostat will react to a program event at the time the
event occurs. However, if SSR is enabled, the thermostat
will react to a program event before the event occurs such
that the desired temperature is reached at the time of the
event, not after.
Autochangeover Deadband Selection (via DIP
switch #7)
Autochangeover deadband can be set to 4 or 6 degrees.
When autochangeover is enabled (via the AUTO button),
the thermostat will automatically change over from heating
to cooling and vice versa, to keep the room temperature in
between the heating and cooling setpoints. The deadband
is the minimum difference between the heating and cooling
setpoints.
Fan Control
AUTO or ON modes, gas or electric heat compatible via
DIP switches (also see Thermostat Output section).
I/O Relays
All thermostat relays are latching type to minimize power
consumption.
Page 7
L3711C 7-DAY PROGRAMMABLE THERMOSTAT
Table 5. L3711C Terminal Designations
Terminal Description
R 24VAC
Y1 First stage cooling
W1 First stage heating
G Fan control
L Service Indicator
C 24VAC common
T Outdoor temperature sensor connection 1
T Outdoor temperature sensor connection 2
Equipment Protection Timers
Minimum Compressor OFF time: 5 minutes
Minimum Compressor ON time: 4 minutes
Minimum Furnace ON time: 3 minutes
Minimum furnace cycle time (elapsed time between any
furnace activation and the next furnace activation): 6 minutes.
Minimum elapsed time between any compressor activation and the next compressor activation: 6 minutes.
NOTE − All protection timers (except the compressor OFF
timer) can be over−ridden if a heating or cooling demand is
initiated or terminated using the UP, DOWN, HEAT, or
COOL buttons.
Equipment Protection Override
Both the minimum compressor OFF timer and the minimum equipment cycle timer can be over−ridden by pressing and holding either the HEAT or COOL button down for 4
seconds.
Over−Temperature Protection
Thermal-mechanical switch opens W1 at 93°F+/−6°F.
Filter Reminder
Settings of Off, 1, 3, 6 or 12 (months of fan run time) are
available. When programmed time has elapsed, a FILTER
indicator is displayed.
Maintenance Reminder
Settings of Off, 6 or 12 (months of chronological time) are
available. When programmed time has elapsed, a MAINTENANCE indicator is displayed.
Service Reminder
The SERVICE indicator is displayed only under the following conditions:
S if the thermostat Y1 terminal has been activated with
24VAC for at least 5 minutes, AND the L terminal is
shorted to the R terminal;
OR
S if the thermostat Y1 terminal has been activated with
24VAC for at least 5 minutes, AND the L terminal is
shorted to the C terminal.
Power Loss/Recovery
Thermostat memory is retained for a minimum of 24 hours
during a power loss (includes retention of clock setting,
program information, HOLD status, programmed temperature setpoint, heat/cool and fan mode settings, filter reminder status, maintenance reminder status, and equipment protection timers). After 24 hours of power loss,
programmed settings will be lost and replaced with default
settings.
IMPORTANT
Power must be applied for at least six consecutive
hours prior to a power loss in order for memory to
be retained for the specified time.
LCD Backlight
Activated for 30 seconds when any button is pressed.
NOTE − During an electrical storm or similar disturbance,
the backlight may activate for a few seconds. This is normal and will no longer occur after the electrical disturbance
has passed.
Thermostat Operating Conditions
35°F to 105°F, 5% to 90% RH
Thermostat Storage Conditions
−40°F to 185°F, 5% to 95% RH
506072−01 02/08
Page 8
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