Honeywell CHRONOTHERM IV T8665A User manual

169-1536–3
USER’S GUIDE
T8665A Chronotherm®IV
Wireless Thermostat
69-1536-3

269-1536–3

369-1536–3
CONTENTS
USING THIS GUIDE .......................................................................................................................................... 5
FEATURES ........................................................................................................................................................ 6
KEYBOARD AND DISPLAY DESCRIPTION .................................................................................................... 7
Keyboard ............................................................................................................................................................ 7
Display ............................................................................................................................................................... 7
ADAPTIVE INTELLIGENT RECOVERYTM CONTROL ..................................................................................... 10
Optimum Comfort and Energy Savings ............................................................................................................. 11
OPERATING YOUR THERMOSTAT ................................................................................................................. 13
Setting System and Fan Keys ............................................................................................................................ 13
Setting the System Key .................................................................................................................................. 14
Setting the Fan Key ........................................................................................................................................ 14
Setting Temporary Temperatures ....................................................................................................................... 15
Changing Temperature to Temporary Setting Until Next Schedule Period ..................................................... 15
Changing and Holding Temperature Setting Indefinitely ................................................................................ 17
Changing Temperature Setting Until a Designated Day and Period (Vacation Hold) ..................................... 18
Replacing the Batteries ...................................................................................................................................... 21

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Contents (Cont)
Using the (Information) Key ......................................................................................................................... 23
Display Current Setting ................................................................................................................................. 23
Display or Reset Filter Timer Settings .......................................................................................................... 24
SETTING THE CLOCK...................................................................................................................................... 25
Set Current Day and Time ................................................................................................................................. 25
Daylight Saving Time ......................................................................................................................................... 27
PROGRAMMING YOUR THERMOSTAT .......................................................................................................... 28
7-Day Program and Operation ........................................................................................................................... 28
7-Day Preprogrammed Schedule ................................................................................................................. 29
Customizing Your Own 7-Day Schedule ....................................................................................................... 30
Programming the First Day ........................................................................................................................... 31
Copying a Day .............................................................................................................................................. 36
Clearing a Program Period ........................................................................................................................... 39
TROUBLESHOOTING....................................................................................................................................... 41
WARRANTY ...................................................................................................................................................... 43
CUSTOMER ASSISTANCE ............................................................................................................................... 45

569-1536–3
USING THIS GUIDE
The T8665A is a multi-functional thermostat. This means it can be used in single or multi-zone applications.
The following symbols will help you identify the features that apply to your system:
– Triple layer of thermostats with the word, zoning, below. These features are available when more
than one thermostat is used with the W8665E RF ZoneTM Panel.
–Tip symbol. Look for helpful tips throughout the guide when you see this symbol.
80
90
70
60
90
80
70
60
ZONING

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FEATURES
•Adaptive Intelligent RecoveryTM Control for comfort
and energy savings.
•Customize the program schedule—program your
own schedule to fit your needs.
•Temporary schedule override—set the thermostat
higher or lower for the current program schedule.
•Permanent schedule override—set the thermostat
higher or lower indefinitely.
•Vacation mode (1 to 255 days) for added comfort
and energy savings. Set the temperature higher or
lower for energy savings while on vacation. At the
same time, set the comfort level you want when
you return.
•Information at the press of a button—use the
(information) key to see the current setpoints.
•Daylight Time key for quick time changes between
Daylight and Standard time.
•Backlit display for improved readability – backlight-
ing on demand (press any key to activate).
•Programmable Fan – your thermostat can activate
the fan in any programming period for improved air
circulation and air cleaning when a Honeywell
wholehouse air cleaner is installed.

769-1536–3
KEYBOARD AND DISPLAY DESCRIPTION
Keyboard
The keyboard is located behind the thermostat cover. Three frequently used keys, increase ▲or decrease ▼
and , are located next to the display. See Fig. 1.
Display
The thermostat displays important information such as day, time, schedule period, temperature, system and fan
operation. See Fig. 2.

869-1536–3
Fig. 1. Thermostat keyboard description.
M20146
Time Set Program
Run
Program
Hold Temp
Set Current
Day/Time
Day Heat/Cool
Settings
Wake
Fan
System
Copy
Daylight
Time
Leave Return Sleep
INCREASE
RAISES TEMPERATURE SETTING
DECREASE
LOWERS TEMPERATURE SETTING
INFORMATION
DISPLAYS CURRENT HEAT/COOL
TEMPERATURE SETTING
PROGRAM SCHEDULING
WAKE LEAVE RETURN SLEEP
ENTERS PROGRAMMING MODE
FAN
SELECTS AUTO/ON
SYSTEM
SELECTS HEAT/OFF/COOL (AUTO)
DIGITAL
DISPLAY
SET CURRENT
DAY/TIME
SETS CURRENT
DAY AND TIME
RUN PROGRAM
RETURNS THERMOSTAT TO
NORMAL OPERATING MODE
HEAT/COOL SETTINGS
SWITCHES BETWEEN HEAT SETPOINTS AND
COOL SETPOINTS WHILE PROGRAMMING
TIME / TIME
SETS TIME
FORWARD OR BACK
HOLD TEMP
SETS A HOLD TEMPERATURE
SETTING AND ACTIVATES
VACATION HOLD FEATURE
DAYLIGHT TIME
SELECTS STANDARD TIME
OR DAYLIGHT SAVING TIME
COPY
COPIES SETTINGS FROM ONE DAY TO
ANOTHER DAY FOR QUICK PROGRAMMING
DAY
SETS DAY OF THE WEEK
WAKE
SET WAKE TIMES
AND
TEMPERATURES
LEAVE
SET LEAVE TIMES
AND
TEMPERATURES
RETURN
SET RETURN TIMES
AND
TEMPERATURES
SLEEP
SET SLEEP TIMES
AND
TEMPERATURES

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Fig. 2. Example of thermostat display.
A
u
t
o
System
F
an
O
f
f
A
u
t
o
Wake
Mon Room
AM
Recovery
Hold for
Filter Days
On
DST
C
oo
l
TueWedThuFriSatSun
Leave Return Sleep
Set Program Set Day/Time Wait Temporary Setting
Heat
M20886
DISPLAYS
EITHER CURRENT
TIME OF DAY OR
PROGRAM TIMES
SHOWS
THERMOSTAT
IS IN THE
SET CURRENT
DAY/TIME MODE
SHOWS
TEMPERATURE
SETTING CHANGED
FOR THIS
PROGRAM
PERIOD
SHOWS TEMPERATURE
DISPLAYED IS THE CURRENT
SET TEMPERATURE
SHOWS
TEMPERATURE
DISPLAYED IS THE
CURRENT ROOM
TEMPERATURE
DISPLAYS EITHER ROOM
OR SET TEMPERATURE
SHOWS CURRENT FAN
KEY POSITION ON/AUTO
SHOWS THERMOSTAT IS
CALLING FOR THE FAN
SHOWS SMART
RESPONSE IS OFF
AND CONVENTIONAL
RECOVERY IS ON
SHOWS THERMOSTAT IS
PROCESSING INFORMATION
AND WAITING TO CALL FOR
HEAT OR COOL
SHOWS ADAPTIVE
INTELLIGENT RECOVERY
TM
IS CHANGING THE
TEMPERATURE TO MEET
THE CURRENT
PROGRAM
S
H
O
W
S
THAT THERM
OS
TAT
I
S
C
ALLIN
G
F
O
R
S
H
O
W
S
CU
RRENT
S
Y
S
TEM KEY P
OS
ITI
ON
HEAT
/O
FF
/COOL
SHOWS CURRENT
PROGRAM PERIOD
OR PERIOD BEING
PROGRAMMED
SHOWS CURRENT
DAY OR DAYS BEING
PROGRAMMED
SHOWS WHEN
THERMOSTAT
IS IN THE
PROGRAMMING
MODE
SHOWS VACATION
HOLD DURATION
SHOWS FILTER
TIMER STATUS
SHOWS SYSTEM ON
DAYLIGHT SAVING TIME

10 69-1536–3
ADAPTIVE INTELLIGENT
RECOVERYTM CONTROL
Your new thermostat is so smart, it’s almost human.
You perceive temperature from a variety of sources,
not only from the air in the room, but also from your
surrounding walls, windows and furnishings. Humans
feel differences in temperature as slight as two
degrees Fahrenheit. Common household thermo-
meters and standard thermostats sense only air temp-
erature, which may not reflect how hot or cold the
room actually feels to you. Your new thermostat reads
both the temperature of the wall and in the air, and
responds to temperature changes as little as one
degree Fahrenheit, so room temperature is more
likely to feel right to you and your family.
The thermostat acts like a computer. When calculat-
ing the time to turn on your heating or cooling system,
it considers air temperature, wall temperature, and the
time you want to reach the comfort temperature. After
considering these three things, Adaptive Intelligent
RecoveryTM control gradually changes the tempera-
ture from the energy savings setting to the comfort
setting (for example, from a heating temperature of
62°at night to 70°in the morning).
The system runs until the comfort temperature you
choose is reached without overshooting the setting.
This saves energy. How do you know when the
system is in recovery? The thermostat displays
“Recovery” whenever the thermostat activates
Adaptive Intelligent RecoveryTM control. See Fig. 3.
So, “Recovery” displays during the recovery time from
Sleep to Wake and from Leave to Return.
Fig. 3. Example of “Recovery” indication.
M20148
Mon
Sleep
Room
System
Fan
Heat
Auto
AM
Heat
Recovery