Honeywell T8665A Chronotherm IV User manual

® U.S. Registered Trademark
Copyright © 2002 Honeywell • • All Rights Reserved
INSTALLATION INSTRUCTIONS
69-1535-3
T8665A Chronotherm®IV
Deluxe Programmable
Wireless Thermostat
APPLICATION
The T8665 Chronotherm® IV Wireless Thermostat
provides electronic control of 24 Vac heating and cooling
systems. It must be used with a W8665 Receiver
Module. Refer to Table 1 for a general description of the
thermostat. The T8665A Thermostats are battery-
powered.
MERCURY NOTICE
If this control is replacing a control that contains
mercury in a sealed tube, do not place your old
control in the trash.
Contact your local waste management authority
for instructions regarding recycling and the
proper disposal of the old thermostat.
INSTALLATION
Accessory Required (Not Included)
Select one of the receiver modules for your application:
— W8665A Receiver Module (RM) for single zone
applications.
— W8665E RF Zone™ Panel for up to three zones.
When Installing this Product...
1. Read these instructions carefully. Failure to follow
the instructions can damage the product or cause
a hazardous condition.
2. Check the ratings given in the instructions and on
the product to make sure the product is suitable for
your application.
3. Installer must be a trained, experienced service
technician.
4. After completing installation, use these instructions
to check out the product operation.
Location
Install the thermostat about 5 ft (1.5m) above the floor in
an area with good air circulation at average temperature.
See Fig. 1.
Do not install the thermostat where it can be affected by:
— drafts, or dead spots behind doors and in corners.
— hot or cold air from ducts.
— radiant heat from sun or appliances.
— concealed pipes and chimneys.
— unheated (uncooled) areas such as an outside wall
behind the thermostat.
Wallplate Installation
The thermostat can be mounted horizontally on the wall.
1. Position and level the wallplate (for appearance
only). The thermostat functions correctly even
when not level.
2. Use a pencil to mark the mounting holes. See Fig.
2.
3. Remove the wallplate from the wall and drill two
3/16 in. holes in the wall (if drywall) as marked. For
firmer material such as plaster, drill two 7/32 in.
holes.
4. Gently tap anchors (provided) into the drilled holes
until flush with the wall.
5. Position the wallplate over the holes.
6. Loosely insert the mounting screws into the holes.
7. Tighten the mounting screws.
Table 1. T8665A Thermostat Description.
T8665 System Changeover System Selection Fan Selection Comments
A Heat-Cool Automatic Heat-Off-Cool-Auto On-Auto System and fan
selections are entered at
keyboard.

T8665A CHRONOTHERM® IV DELUXE PROGRAMMABLE WIRELESS THERMOSTAT
69-1535-3 2
Fig. 1. Typical thermostat location.
Fig. 2. Mounting the wallplate.
Mounting Thermostat
1. Engage tabs at the top of the thermostat and wall-
plate. See Fig. 3.
2. Press lower edge of case to close and latch.
NOTE: To remove the thermostat from the wall, first pull
out at the bottom of the thermostat; remove top
last.
Fig. 3. Mounting thermostat on wallplate.
5 FEET
[1.5 METERS]
YES NO
NO
NO
M1010
6
WALL
MOUNTING
HOLES
M20592
MOUNTING
SCREWS
WALL
ANCHORS (2)
M1462
8
PRESS LOWER
EDGE OF CASE
TO LATCH.
ENGAGE TABS
AT TOP OF
THERMOSTAT
AND WALLPLATE.
A.
B
.

T8665A CHRONOTHERM® IV DELUXE PROGRAMMABLE WIRELESS THERMOSTAT
3 69-1535-3
Using Thermostat Keys
The thermostat keys are used to:
• set current day and time.
• program times and setpoints for heating and cooling.
• temporarily override program temperatures
• display present setting,
• configure Installer Setup,
• check self-test,
• set the system operation,
• set the fan operation.
See Fig. 4 for key locations.
Fig. 4. T8665A key locations and descriptions.
Setting up T8665A to Send Signal
to W8665A,E Receiver Module
The T8665A Thermostat must be set up to send signals
to the W8665 Receiver Module. Use the W8665A
Receiver for single-zone applications. Use the W8665E
RF Zone™ Panel for up to three T8665A Thermostats for
multizone applications.
Single Zone Applications (one T8665A/
one W8665A)
1. Place the Zone 1 DIP switch on the W8665A
Receiver to the On position.
NOTE: Observe that the Zone 1 LED on the W8665
flashes.
2. Press the thermostat Fan key to the On position.
The receiver accepts the message, stores identity
and then stops flashing the Zone 1 LED. The ther-
mostat is now set up to send signals the W8665A
Receiver.
NOTE: The word On and a fan blade appear in the
thermostat display to indicate the thermostat is
calling for the fan to turn on.
3. Set the System and Fan keys to the desired loca-
tions.
NOTE: At any time, if you want to stop the thermostat
from sending signals to the W8665 Receiver,
simply turn the DIP switch to the Off position.
Follow the instructions in steps above to set up
the thermostat again to send signals to the
W8665A Receiver.
Multizone Applications (Up to three T8665A/
one W8665E)
IMPORTANT
The thermostats must be set up one zone at a
time to ensure a unique address is used for
each zone.
1. Place the Zone 1 DIP switch on the W8665E
Receiver to the On position.
NOTE: Observe that the Zone 1 LED on the W8665
flashes.
2. Press the thermostat Fan key to the On position.
The Receiver accepts the message, stores the
identity of that zone, and stops flashing the Zone 1
LED. The thermostat is now set up to send signals
to Zone 1 of the W8665E Receiver.
NOTE: The word On and a fan blade appear in the
thermostat display to indicate the thermostat is
calling for the fan to turn on.
3. Set the System and Fan keys to the desired loca-
tions.
NOTE: At any time, if you want to stop the thermostat
from sending signals to the W8665 Receiver,
simply turn the DIP switch to the Off position.
Follow the instructions in steps above to set up
the thermostat again to send signals to the
W8665E Receiver.
4. Repeat steps 1-3 for zones two and three.
M20166
Time Set Program
System Fan
Run
Program
Hold Temp
Set Current
Day/Time Wake Leave Return Sleep
Day Heat/Cool
Settings
Daylight
Time Copy
INCREASE TEMPERATURE
SETTING OR SCROLL
FORWARD THROUGH
INSTALLER SETUP OPTIONS
DECREASE TEMPERATURE
SETTING OR SCROLL
BACKWARD THROUGH
INSTALLER SETUP OPTION
S
DISPLAY INFORMATION
SUCH AS PRESENT
SETTINGS
RETURN TO
NORMAL
OPERATIONS
ENTER
INDEFINITE
OR TIMED
HOLD MODE
SET CURRENT
DAY AND TIME
SET CURRENT OR
PROGRAM DAY
CHANGE BETWEEN
DAYLIGHT SAVINGS
AND STANDARD TIME
I
NCREASE TIME SETTING
O
R SCROLL FORWARD
T
HROUGH INSTALLER SETUP
A
ND SYSTEM TEST
DECREASE TIME SETTING OR
SCROLL BACKWARD THROUGH
INSTALLER SETUP AND SYSTEM TEST
COPY ONE PROGRAMMED
DAY TO ANOTHER DAY
SET WAKE TIMES
AND SETPOINTS
CHANGE BETWEEN
HEATING AND COOLING
SETPOINTS
SET LEAVE TIMES
AND SETPOINTS SET RETURN TIMES
AND SETPOINTS
SET SLEEP TIMES
AND SETPOINTS
SELECT SYSTEM
OPERATION
SELECT FAN
OPERATION

T8665A CHRONOTHERM® IV DELUXE PROGRAMMABLE WIRELESS THERMOSTAT
69-1535-3 4
5. Attach the zone number stickers, included with the
thermostat, onto the thermostat case on the inside
of the thermostat cover. See Fig. 5.
Fig. 5. Zone stickers included with T8665A
Thermostat.
SETTINGS
System and Fan Settings
The system default setting is Heat and the fan default
setting is Auto. Use the System and Fan keys to change
the settings. See Fig. 6. The fan settings can be set for
each program period individually. The system selection is
for all the program periods.
System settings control the thermostat operation as
follows:
Heat: The thermostat controls the heating.
Off: Both the heating and cooling are off.
Cool: The thermostat controls the cooling.
Auto: The thermostat automatically changes between
heating and cooling operation, depending on the
indoor temperature.
Fan settings control the system fan as follows:
On: Fan operates continuously.
Auto: Fan operates with equipment.
Fig. 6. Thermostat System and Fan key locations.
NOTE: Always press the keys with your fingertip or sim-
ilar blunt tool. Sharp instruments like a pen or
pencil point can damage the keyboard.
Programmed Temperature Settings
Refer to Table 2 for the default program. If the daytime
energy savings period is not used, press the period key
(Leave or Return) until the time is blank. The fan setting
feature is available on select thermostat models. See
Owner’s Guide for complete instructions on changing the
program.
Table 2. Default Program Settings.
Place one label inside
each thermostat door.
Zone 1
Zone 2 Zone 3
M1342
6
Period Time
Heat
Setpoint
Cool
Setpoint
Fan
Setting
Wake 6:00
AM
70°F
(21°C)
78°F
(25.5°C)
Auto
Leave 8:00
AM
62°F
(16.5°C)
85°F
(29.5°C)
Auto
Return 6:00
PM
70°F
(21°C)
78°F
(25.5°C)
Auto
Sleep 10:00
PM
62°F
(16.5°C)
82°F
(28°C)
Auto
M14625
HoldTemp
Run
Program
Copy
Daylight
Time
Set Current
Day/Time
System Fan
Time Set Program
Day System
Fan
Wake Leave Return Sleep
Heat/Cool
Settings

T8665A CHRONOTHERM® IV DELUXE PROGRAMMABLE WIRELESS THERMOSTAT
5 69-1535-3
INSTALLER SETUP
NOTE: For most applications, the thermostat factory-
settings do not need to be changed. Review the
factory default settings in Table 3 and, if no
changes are necessary, go to the Installer Self-
Test section.
The Installer Setup is used to customize the thermostat
to specific systems. Some of the options include
temperature display and system changeover. Installer
Setup numbers are listed in Table 3. The table includes
all the configuration options and the factory-settings for
the T8665.
A combination of key presses are required to use the
Installer Setup feature:
— To enter the Installer Setup, press and hold the
Information i key with the increase Vand decrease W
keys until the first number is displayed. All display
segments appear for approximately three seconds
before the number is displayed. See Fig. 7 and 8.
— To advance to the next Installer Setup, press the Time
Vkey.
— To change a setting, use the increase Vor decrease
Wkey.
— To scroll the Installer Setup numbers backward, press
the Time Wkey.
— To exit the Installer Setup, press Run Program.
Fig. 7. DIsplay of all LCD segments.
Fig. 8. Display of Installer Setup number
and settings.
CAUTION
Equipment Damage Hazard.
Electric heat and heat pump systems must
run with fan.
Configure to 1 in Installer Setup number 2 to
prevent equipment damage.
IMPORTANT
Only configured numbers are shown on the
device.For example: If thermostat does not
have a system key, Installer Setup Number 12
will not display. Review Table 3 factory settings
and mark any desired changes in the Actual
Settings column. When Installer Setup is com-
plete, review the settings to confirm they Mat-
thew system.
M1455
9
Aux Ht
Set Day/TimeSet Program
Mon
Wake Leave Return Sleep OutdoorRoom
Filter
Wait
System
Fan
Em Hea
t
On
Auto
Of
f
Coo
l
Auto
AM
PM
Hold for
Heat Cool
Repl Batt
Recovery
DST
TueWedThu Fri Sat Sun
Days
Temporary Setting
Em Ht
M14618
INSTALLER SETUP
NUMBER DISPLAY
(COLUMN 2 OF TABLE 3)
FACTORY SETTING OR OTHER
CHOICE DISPLAY (COLUMN 3
OR 5 OF TABLE 3)

T8665A CHRONOTHERM® IV DELUXE PROGRAMMABLE WIRELESS THERMOSTAT
69-1535-3 6
Table 3. Thermostat Installer Setup Options.
Select
Installer Setup
Number
(Press Time V
key to
change)
Factory Setting
Other Choices
(Press Vor Wkey to change)
Actual
SettingDisplay Description Display Description
Not used 1 — — — — —
Fan operationa2 0 Conventional
applications where
equipment controls
fan operation in heat
mode
1 Heat pump or electric heat
applications where
thermostat controls fan
operation in heat mode
Not used 3 — — — — —
Heating cycle
rate
4 6 6—6 cph used for
conventional heat
1, 3 or 9 1—1 cph used for radiant
floor heat, gravity system
3—3 cph used for hot
water systems or high
efficiency furnaces
9—9 cph used for electric
heat systems
Not used 5 thru 11 — — — — —
System setting
adjustment
12 1Manual changeover 0 or 2 0—Auto changeover
2—Auto only
Adaptive
Intelligent
Recovery™
control
13 0Adaptive Intelligent
Recovery™ control
is activated (system
starts early so
setpoint is reached
by start of program
period)
1Conventional recovery
(system starts recovery at
programmed time)
—
Degree
temperature
display
14 0Temperature is
displayed in °F
1Temperature is displayed
in °C
Not used 15 — — — — —
Clock format 16 012-hour clock format 124-hour clock format
Not used 17 and 18 — — — — —
Extended fan
operation in
heatinga
19 0No extended fan
operation after the
call for heat ends
1Fan operation is extended
90 seconds after the call
for
heat ends.
Extended fan
operation in
coolinga
20 0No extended fan
operation after the
call for cool ends
1Fan operation is extended
90 seconds after the call
for
cool ends.
Not used 21 thru 29 — — — — —
Deadband 30 3 Heating and cooling
setpoints can be set
no closer than 3°F
(1.5°C)
4 thru 10 Heating and cooling
setpoints can be set no
closer than the chosen
value:
4—4°F (2°C)
5—5°F (2.5°C)
6—6°F (3°C)
7—7°F (3.5°C)
8—8°F (4°C)
9—9°F (4.5°C)
10—10°F (5°C)
Not used 31 and 32 — — — — —
Minimum off
time for the
compressor
33 5five-minute
minimum off time for
the compressor
0 thru 4 Minimum number of
minutes (0 thru 5) the
compressor will be off
between calls for the
compressor

T8665A CHRONOTHERM® IV DELUXE PROGRAMMABLE WIRELESS THERMOSTAT
7 69-1535-3
aNumber 2 must be set to 1 to extend fan operation.
IMPORTANT
Review the settings to confirm they match the
system. Press Run Program to exit the Installer
Setup. The thermostat has saved the Iinstaller
Setup changes and initiated a reset to operate
using the new settings. Be sure to set the cur-
rent day and time immediately.
Temperature
range stops in
heating
34 90 Highest setpoint
heating can be set
to
40 to 89 Temperature range (1°F
increments) heating
setpoint can be set to
Temperature
range stops in
cooling
35 45 Lowest setpoint
cooling can be set to
46 to 99 Temperature range (1°F
increments) cooling
setpoint can be set to
Not used 36 — — — — —
Temperature
display
adjustment
37 0No difference in
displayed
temperature and
actual room
temperature
3 thru
-3
1—Display adjusts to 1°F
higher than actual room
temperature
2—Display adjusts to 2°F
higher than actual room
temperature
3—Display adjusts to 3°F
higher than actual room
temperature
-1—Display adjusts to 1°F
lower than actual room
temperature
-2—Display adjusts to 2°F
lower than actual room
temperature
-3—Display adjusts to 3°F
lower than actual room
temperature
Furnace air
filter timer
(pushbutton
System keys)
43 230 days
(System run time)
0, 1, 3, 4 0—Off
1—10 days
3—60 days
4—120 days
(Time is counted when
heat, cool or fan is
running.)
Humidifier pad
monitor
44 0Off 1, 2, 3 1—90 days
2—180 days
3—365 days
(Time is counted by
calendar days in heat
mode.)
Ultraviolet air
treatment (UV)
system lamp
monitor
45 0Off 11—365 days
(Time is counted by
calendar days in any
mode.)
Table 3. Thermostat Installer Setup Options. (Continued)

T8665A CHRONOTHERM® IV DELUXE PROGRAMMABLE WIRELESS THERMOSTAT
69-1535-3 8
Setting Current Day and Time
1. Press Set Current Day/Time.
NOTE: On initial powerup or after an extended power
loss, 1:00 pm flashes on the display until a key
is pressed.
2. Press Day until the current day is displayed.
NOTE: Sun=Sunday, Mon=Monday,
Tue=Tuesday, Wed=Wednesday,
Thu=Thursday, Fri=Friday, Sat=Saturday.
3. Press Time Vor Time Wuntil the current time is
displayed.
NOTE: Tapping Set Current Day/Time changes the time
in one-hour increments.
NOTE: If the current time is Daylight Savings Time,
press Daylight Time until DST is displayed.
4. Press Run Program.
Viewing or Resetting Timer Settings
When the thermostat activates a timer, the thermostat
flashes Filter until the timer resets.
1. Rest the timer by pressing the ikey until the
expired time is displayed.
2. Press the Time Vkey to reset the timer.
3. Press the Run Program key.
NOTE: You can view the number of days remaining at
any time by pressing the ikey three or four
times. If more than one timer is active, all active
timers show sequentially when pressing the i
key several times.
M1461
9
Time Set Program
System Fan
Run
Program
Hold Temp
Set Current
Day/Time
Set Current
Day/Time Wake Leave Return Sleep
Day Heat/Cool
Settings
Daylight
Time Copy
Set Day/Time
Mon
PM
M1462
0
Time Set Program
System Fan
Run
Program
Hold Temp
Set Current
Day/Time Wake Leave Return Sleep
Day
Day Heat/Cool
Settings
Daylight
Time Copy
Set Day/Time
PM
Tue
M1462
1
Time Set Program
System Fan
Run
Program
Hold Temp
Set Current
Day/Time Wake Leave Return Sleep
Day
Time
Heat/Cool
Settings
Daylight
Time Copy
Set Day/Time
AM
Tue
M1462
2
Time Set Program
System Fan
Run
Program
Hold Temp
Set Current
Day/Time Wake Leave Return Sleep
Day Heat/Cool
Settings
Daylight
Time
Daylight
Time
Copy
Set Day/Time
AM
DST
Tue
M1462
3
Time Set Program
System Fan
Run
Program
Run
Program Hold Temp
Set Current
Day/Time Wake Leave Return Sleep
Day Heat/Cool
Settings
Daylight
Time Copy Wake Room
System
Fan
Heat
Auto
AM
DST
Tue
M2024
3
Filter Days
M2024
4
Filter Days

T8665A CHRONOTHERM® IV DELUXE PROGRAMMABLE WIRELESS THERMOSTAT
9 69-1535-3
INSTALLER SYSTEM TEST
Use the Installer System Test to check the thermostat
operation. Refer to Table 4 for a list of the available
Installer System Tests.
CAUTION
Equipment Damage Hazard.
Compressor damage can result if compressor
is cycled too quickly.
Be aware that compressor minimum off time is
bypassed during the Installer System Test.
To start the system test:
1. Press and hold increase Vand decrease Wat
the same time until 10 appears.
2. Observe all segments of the display are displayed
before the 10 appears. See Fig. 9 and 10.
Fig. 9. LCD segments display.
Fig. 10. Test number display.
Refer to Table 5 for the instructions and description of the
specific tests.
NOTE: Press Time Vto advance to the next test and
press Time Wto go back to the previous test.
Press Run Program to exit the system test.
NOTE: Press any key and the displayed number will change. Press TIme Wto go to the previous test and Time V
to go to the next test. The Run Program key will not exit this test. Press Time Vor Time Wand then the Run
Program key to exit.
Table 4. Tests Available in Installer System Test.
Test Number System Test Description
10-19 Heating equipment can be turned
on and off.
30-39 Cooling equipment can be turned
on and off.
40-49 Fan equipment can be turned on
and off.
60 0 to
60 19
Keyboard keys test.
70-79 Thermostat information, including
date code and software versions,
are displayed.
M1455
9
Aux Ht
Set Day/TimeSet Program
Mon
Wake Leave Return Sleep OutdoorRoom
Filter
Wait System
Fan
Em Hea
t
On
Auto
Of
f
Coo
l
Auto
AM
PM
Hold for
Heat Cool
Repl Batt
Recovery
DST
TueWedThu Fri Sat Sun
Days
Temporary Setting
Em Ht
M1461
2
Table 5. Installer System Test Options.
Key to Press Test Number Description
Heating Equipment System Test
Time 10 Enter heating equipment system test.
V11 Heat comes on. When Installer Setup number 2 is 1, the system fan is also
energized.
W12 Heat and system fan turn off.
Cooling Equipment System Test
Time 30 Change from heating to cooling equipment system test.
V31 Cool and system fan come on.
W30 Cool and system fan turn off.
Fan Equipment System Test
Time 40 Change from cooling to fan equipment system test.
V41 Fan comes on.
W40 Fan turns off.
Key Operation System Test
Time 60 2 Change from fan to key operation system test.

T8665A CHRONOTHERM® IV DELUXE PROGRAMMABLE WIRELESS THERMOSTAT
69-1535-3 10
Thermostat Information
1. Press the Time key to access the thermostat infor-
mation.
2. Press the increase Vkey to display the produc-
tion date code. The first two large digits are the
month and the third digit is the last digit of the year
(example: 027=February 1997).
3. Press the increase key Vagain to display the soft-
ware identification code. (Example: 02 = software
ID code 2).
4. Press the increase key Vagain to display the
software revision number (example:001 = revision
number 1).
5. Press the increase Vkey again to display the
EEPROM identification code (example: 314 =
EEPROM ID 314).
6. Press the Run Program key to exit the system test.
The system test times out after four minutes with-
out any key presses.
M1461
3
M1461
4
M1461
5
M1461
7

T8665A CHRONOTHERM® IV DELUXE PROGRAMMABLE WIRELESS THERMOSTAT
11 69-1535-3
TROUBLESHOOTING GUIDE
For troubleshooting, see Table 6.
Table 6. Troubleshooting Guide.
Symptom Possible Cause Action
Display does not
come on.
Thermostat is not being
powered.
Check if batteries are present and installed correctly.
— If batteries are present and installed correctly, replace thermo-
stat.
Temperature
display is
incorrect.
Room temperature display
has been reconfigured.
Enter Installer Setup number 37 and reconfigure the display.
Thermostat is configured
for °F or °C display.
Enter Installer Setup number 14 and reconfigure the display.
Poor choice of thermostat
location.
Relocate the thermostat.
Temperature
settings do not
change.
(Example:
Cannot set the
heating higher or
the cooling
lower.)
The upper or lower
temperature limits were
reached.
Check the temperature setpoints:
• Heating limits are 40 to 90°F (4.5 to 32°C)
• Cooling limits are 48 to 99°F (7 to 35°C)
The setpoint temperature
range stops were
configured.
Check Installer Setup numbers 34 and 35 and reconfigure the setpoint
stops.
Heating does not
come on.
Thermostat is calling for
heat (flame icon is in
display).
•Troubleshoot the W8665 Receiver Module.
•Troubleshoot the heating equipment.
Thermostat is not calling
for heat (no flame icon is in
display).
•Raise heating setpoint above room temperature.
•Check if the W8665 is set up to receive signals from this thermostat.
— Set up W8665 to receive signals.
Thermostat minimum off
time is activated.
Wait up to five minutes for the system to respond.
System selection is not set
to Heat.
Set system selection to Heat.
Heating setpoint is below
room temperature.
Check heating setpoint. Set heating setpoint to desired temperature.
Cooling does not
come on.
Thermostat minimum off
time is activated.
•Wait up to five minutes for the system to respond.
•Enter Installer Setup number 33. Reconfigure minimum off time
(if required).
System selection is not set
to Cool.
Set system selection to Cool.
Cool setpoint is above
room temperature.
Check cooling setpoint. Set cooling setpoint to desired temperature.
Thermostat is calling for
cool (snowflake is in
display).
•Troubleshoot cooling equipment.
•Troubleshoot W8665 Receiver Module.
Thermostat is not calling
for cool (no snowflake icon
is in display).
•Check if the W8665 is set up to receive signals from the thermostat.
— Set up W8665 to receive signals.
System on
indicator
( = heat,
= cool) is
displayed, but no
warm or cool air
is coming from
the registers.
Fan operation set for 0
(conventional heat) when it
should be set for 1 (electric
heat).
Enter Installer Setup number 2 and reconfigure the fan operation.
Conventional heating
equipment turns on the fan
when the furnace has
warmed up to a setpoint.
Wait a minute after seeing the on indicator and then check the
registers.
Heating or cooling
equipment is not operating.
Verify operation of heating or cooling equipment in self-test.
Thermostat
backlight
appears dim.
Backlight may fade over
the life of the batteries.
•Wait unit Replace Battery indicator is illuminated and replace
batteries.
•Replace batteries now.

69-1535-3G.H. Rev. 11-02Printed in U.S.A. www.honeywell.com/yourhome
T8665A CHRONOTHERM® IV DELUXE PROGRAMMABLE WIRELESS THERMOSTAT
Automation and Control Solutions
Honeywell Honeywell Limited-Honeywell Limitée
1985 Douglas Drive North 35 Dynamic Drive
Golden Valley, MN 55422 Scarborough, Ontario
M1V 4Z9
FCCID: CFS8DL5800STAT
CANADA: 1748A12111
This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions:
(1) This device may not cause harmful interference, and
(2) This device must accept any interference received, including interference that may cause undesired operation.
FEDERAL COMMUNICATIONS COMMISSION (FCC) STATEMENT
This equipment has been tested to FCC requirements and has been found acceptable for use. The FCC requires the
following statement for your information:
This equipment generates and uses radio frequency energy and, if not installed and used properly; that is, in strict
accordance wih the manufacturer’s instructions, may cause interference to radio and television reception. It has been
type tested and found to comply with the limits for a Class B computing device in accordance with the specifications in
Part 15 of FCC Rules, which are designed to provide reasonable protection against such interference in a residential
installation. However, there is no guarantee that interference will not occur in a particular installation. If this equipment
does cause interference to radio or television reception, which can be determined by turning the equipment off and on,
the user is encouraged to try to correct the interference by one or more of the following measures:
• If using an indoor antenna, have a quality outdoor antenna installed.
• Reorient the receiving antenna until interference is reduced or eliminated.
• Move the radio or television receiver away from the receiver/control.
• Move the antenna leads away from any wire runs to the receiver/control.
• Plug the receiver/control into a different outlet so that it and the radio or television receiver are on different branch
circuits.
If necessary, the user should consult the dealer or an experienced radio/television technician for additional
suggestions. The user or installer may find the following booklet prepared by the Federal Communications Commission
helpful:
“Interference Handbook”
This booklet is available under Stock No. 004-000-00450-7 from the US Government Printing Office, Washington, DC
20402.
The user shall not make any changes or modifications to the equipment unless authorized by the Installation
Instructions or User’s Manual. Unauthorized changes or modifications could void the user’s authority to operate the
equipment.