Honeywell T8631A User manual

Chronotherm III
for Comfort and Convenience
OWNER'S GUIDE
Residential and Residential and Helping You Control Your World
Building Controls Division Building Controls Division
Honeywell Inc. Honeywell Limited—Honeywell Limitée
1985 Douglas Drive North 740 Ellesmere Road
Golden Valley, Minnesota 55422 Scarborough, Ontario
M1P 2V9
Congratulations! You made a smart choice when you purchased your new Honeywell Communicating
Chronotherm III Thermostat. It’s the smart thermostat that:
■ Keeps you comfortable by automatically calculating exactly when the furnace or air conditioning
should go on to have the house at the desired comfort temperature by the time you wake up.
■ Savesthemaximumamountofenergyandmoney byrememberingtoautomaticallysetbacktheheat
or air conditioning when you leave home.
■ Providestheultimateincomfortandconvenience bycomingtoyoualreadyprogrammed.Butit’syour
choice—use the preprogrammed schedule or set your own.
■ Can be connected to a Honeywell's TotalHome system for external access and control. TotalHome
system devices communicate using HBus, a Honeywell communications protocol.

Features
3Set the cooling temperatures. See
page 7.
4Set the system and fan switches. See
page 12.
1Setthecurrenttimeandday.Seepage1.
2Set the program schedule and heating
temperatures. See page 2.
Simple Four-Step Programming
Of course, you can use the schedule preprogrammed into your new thermostat. See
Glossary,page40-42).But it’saneasymattertoprogramthethermostattofityourlifestyle.
Choose
manual or
programmed
thermostat
operation.
Program up
to four
different time
periods in
each
schedule.
Set different
schedules for
weekdays,
Saturday, and
Sunday.
Choose
system and
fan operation
with the
thermostat
switches (on
subbase).
AUX. HT. and EM. HT. on T8631R.
See Glossary, page 40.
Bypass the
stored
program for
a single
period.
Set the
temperature
warmer or
cooler with the
touch of a key.
Monitor thermostat operation; read
current time and room temperature at
a glance.
Check status light to see if the thermostat
is on, even in the dark.

TABLE OF CONTENTS
Programming Your Thermostat ...........................1-13
Setting the current day and time ............................. 1
Setting the program schedule and heating tempera-
tures....................................................................2
Setting the cooling temperatures ............................ 7
Setting the system and fan switches on the
subbase ............................................................ 12
Operating Your Thermostat ...............................14-20
Temporarily changing the program ....................... 14
Permanently changing the program ......................15
Operating the thermostat manually .......................16
Canceling program settings...................................17
Checking the program times and temperatures .... 18
Checking the current temperature setting .............19
External access and control of thermostat ............20
Maintaining Your Thermostat ............................21-24
Removing the thermostat ......................................21
Replacing the thermostat ...................................... 22
Replacing the batteries..........................................23
Power outages ...................................................... 24
Adaptive Intelligent Recovery™ ........................25-28
Selecting Recovery Setting................................29-30
Heat Pumps with Supplemental Heat................31-32
Answering Common Questions About the Chrono-
therm III Thermostat............................................33-36
Saving Energy Across the U.S...........................37-39
Glossary...............................................................40-42
Your Personal Program ......................................43-44
Troubleshooting Guide.......................................45-46
Quick Reference to the Keys .............................47-48
Index.....................................................................49-50
Warranty.................................................................... 51
i

STEP 1
SETTING THE CURRENT
DAY AND TIME
You can program this thermostat
only on the wall with 24 Vac applied
to R and C terminals.
Always press the keys with your
fingertip or similar blunt tool. Sharp
instruments like a pen or pencil
point can damage the keyboard.
NOTE: Check the glossary, page
40, for definitions of unfamiliar
words.
1
2
SET
PRESENT
DAY/TIME
MON
PM
Press and release. The display
shows 1:00 PM Mon.
Press and hold until the current day
appears in the display.
Press and hold until the current time
appears in the display. Be sure AM
or PM appears as desired.
You have programmed the current
day and time. Go on to Step 2.
DAY
AHEAD
BACK
TUE
PM
TUE
PM
STEP 2
SETTING THE PROGRAM
SCHEDULE AND HEATING
TEMPERATURES
Before You Begin…
The schedule form on page 43
provides an opportunity to plan your
schedule.
Now…
Start by programming the WAKE
time and temperature for weekdays.
The thermostat requires a program
for WAKE. You can program
LEAVE, RETURN and SLEEP or
not, as you please.
SET
HEAT/COOL
Press and release. Note that the
display shows WAKE, the
preprogrammed time and tempera-
ture.
If the display reads COOL, press and
release to switch to HEAT.
If display reads SAT or SUN, press
and hold until MON TUE WED THU
FRI appears.
Press and hold until the display
shows the desired starting time. If
using T8631A in Conventional
Recovery ( ■■ visible in display). See
Glossary section. With Convential
Recovery the time should be set 30
or more minutes ahead of desired
comfort time to get the house
comfortable.
WAKE
DAY
AHEAD
BACK
MON TUE WED THU FRI ON HEAT
WAKE
AM
SET
PT
MON TUE WED THU FRI ON HEAT
WAKE
AM
SET
PT
MON TUE WED THU FRI ON HEAT
WAKE
AM
SET
PT
MON TUE WED THU FRI ON HEAT
WAKE
AM
SET
PT
PROGRAMMING YOUR THERMOSTAT

4
3
Program the LEAVE time and
temperature, if desired.
NOTE: You can cancel the LEAVE,
RETURN or SLEEP program by
holding down the key until the
time and temperature disappear
from the display.
PROGRAMMING YOUR THERMOSTAT
AHEAD
BACK
WARMER
COOLER
WARMER
COOLER
MON TUE WED THU FRI ON HEAT
LEAVE
SET
PT
LEAVE
MON TUE WED THU FRI ON HEAT
LEAVE
AM
SET
PT
MON TUE WED THU FRI ON HEAT
LEAVE
AM
SET
PT
Press and release. The display
shows LEAVE, but no time or
temperature.
Press and hold until the display
shows the desired starting time.
Press and hold until the display
shows the desired temperature.
Program the RETURN time and
temperature, if desired. Press and release. The display shows RETURN, but no time or
temperature.
Press and hold until the display
shows the desired starting time.
T8631A using Conventional Recov-
ery ( ■■ visible in display) should be
set 30 or more minutes ahead of
desired comfort time.
Press and hold until the display
shows the desired temperature.
AHEAD
BACK
RETURN
MON TUE WED THU FRI ON HEAT
RETURN
SET
PT
MON TUE WED THU FRI ON HEAT
RETURN
PM
SET
PT
Press and hold until the display
shows the desired temperature.
If the display starts to blink while
you are holding down TEMPERA-
TURE WARMER or COOLER, you
have reached the setting limit.
MON TUE WED THU FRI ON HEAT
WAKE
AM
SET
PT
WARMER
COOLER
MON TUE WED THU FRI ON HEAT
RETURN
PM
SET
PT
Press and release. The display
shows SLEEP, the preprogrammed
time and temperature.
Press and hold until the display
shows the desired starting time.
SLEEP
Program the SLEEP time and
temperature, if desired.
MON TUE WED THU FRI ON HEAT
SLEEP
PM
SET
PT
AHEAD
BACK
MON TUE WED THU FRI ON HEAT
SLEEP
PM
SET
PT

MON TUE WED THU FRI ON HEAT
SLEEP
PM
SET
PT
PROGRAMMING YOUR THERMOSTAT
5
WARMER
COOLER
DAY
LEAVE
RETURN
AHEAD
BACK
WARMER
COOLER
SUN ON HEAT
SLEEP
PM
SET
PT
DAY
SLEEP
WAKE LEAVE
RETURN
AHEAD
BACK
WARMER
COOLER
RUN
PROGRAM
6
Press and hold until the display
shows the desired temperature.
Press and release until SAT appears
on the display.
Press WAKE, LEAVE, RETURN or
SLEEP to select the time period.
Press the AHEAD/BACK keys to set
the time and the WARMER/COOLER
keys to set the temperature.
SAT ON HEAT
SLEEP
PM
SET
PT
Set the SATURDAY schedule. Use
the same procedure as for week-
days.
SLEEP
WAKE
Set the SUNDAY schedule. Use
the same procedure as for week-
days.
Press and hold until SUN appears on
the display.
Press WAKE, LEAVE, RETURN or
SLEEP to select the time period.
Press the AHEAD/BACK keys to set
the time and the WARMER/COOLER
keys to set the temperature.
You have completed setting the
program schedule and heating
temperatures. To set air conditioning,
go to Step 3,
If you do not want to program cool
temperature, skip Step 3 and press
RUN PROGRAM key.

7
8
PROGRAMMING YOUR THERMOSTAT
STEP 3
SETTING THE COOLING
TEMPERATURES
The program times are the same
for both heating and cooling. Only
the cooling temperatures need to
be programmed if you have already
programmed for heating. If you
change program times for cooling,
you are also changing them for
heating! To set times as you
program the cooling temperatures,
use the TIME AHEAD and BACK
keys as described in Step 2.
First program the WAKE tempera-
ture for weekdays.
WAKE Press and release. The display
shows WAKE, the time and tempera-
ture you programmed for heating.
Press and release so COOL shows
on the display, along with the
programmed cooling temperature.
If display reads SAT or SUN, press
and hold until MON TUE WED THU
FRI appears.
SET
HEAT/COOL
DAY
SUN ON HEAT
WAKE
AM
SET
PT
MON TUE WED THU FRI COOL
WAKE
AM
SET
PT
SUN COOL
WAKE
AM
SET
PT
Press and hold until the display
shows the desired temperature.
If the display blinks while you hold
down TEMPERATURE WARMER or
COOLER, you have reached the
setting limit.
WARMER
COOLER
MON TUE WED THU FRI COOL
WAKE
AM
SET
PT
Press and release. The display
shows LEAVE, the time programmed
for heating and 78°F.
Press and hold until the display
shows the desired temperature.
Program the LEAVE temperature, if
desired.
LEAVE
MON TUE WED THU FRI COOL
LEAVE
AM
SET
PT
MON TUE WED THU FRI COOL
LEAVE
AM
SET
PT
WARMER
COOLER
Program the RETURN tempera-
ture, if desired.
RETURN
Press and release. The display
shows RETURN, the time pro-
grammed for heating and 78°F.
MON TUE WED THU FRI COOL
RETURN
PM
SET
PT

PROGRAMMING YOUR THERMOSTAT
9
10
WARMER
COOLER
MON TUE WED THU FRI COOL
RETURN
PM
SET
PT
Press and hold until the display
shows the desired temperature.
Program the SLEEP temperature if
desired. Press and release. The display shows SLEEP, the time programmed
for heating and 78°F.
Press and hold until the display
shows the desired temperature.
SLEEP
MON TUE WED THU FRI COOL
SLEEP
PM
SET
PT
WARMER
COOLER
MON TUE WED THU FRI COOL
SLEEP
PM
SET
PT
Set the cooling temperatures for
the SATURDAY schedule. Use the
same procedure as for weekdays.
Press and hold until SAT appears on
the display.
DAY
SAT COOL
SLEEP
PM
SET
PT
Press WAKE, LEAVE, RETURN or
SLEEP to select the time period.
Press the WARMER/COOLER keys
to set the temperature.
SLEEP
WAKE LEAVE
RETURN
WARMER
COOLER
Set the cooling temperatures for
the SUNDAY schedule. Use the
same procedure as for weekdays. DAY Press and hold until SUN appears on
the display.
Press WAKE, LEAVE, RETURN or
SLEEP to select the time period.
SUN COOL
SLEEP
PM
SET
PT
SLEEP
WAKE LEAVE
RETURN

PROGRAMMING YOUR THERMOSTAT
11
12
Press the WARMER/COOLER keys
to set the temperature.
You have completed programming
the cooling temperatures.
Press and release to start the
program.
Go to Step 4.
WARMER
COOLER
RUN
PROGRAM
TUE
LEAVE
PM
SET
PT
STEP 4
SETTING THE SYSTEM AND FAN
SWITCHES ON THE SUBBASE
The T8631A does not have the EM.
HT. switch position. Note the
positions provided on your sub-
base, then set the switch(s) as
desired.
First set the fan switch.
Then set the system switch.
FAN ON: Use for improved air
circulation during special occasions
or for more efficient electronic air
cleaning. The fan runs continuously.
FAN AUTO: Normal setting for most
homes and businesses. T8631A: the
fan starts and stops with the air
conditioner and with the heating
equipment when the fan switch (4A)
is set for electric heat. When 4A is
set for conventional heat, the fan is
controlled by the heating equipment.
T8631R: the fan starts and stops with
the compressor in heat pump
systems when the system switch is
set to HEAT or COOL. When system
switch is set to EM. HT., the fan
operates with the auxiliary heat (on
some models).
EM. HT. (T8631R only): The thermo-
stat controls only the backup heat.
The heat pump is off.
FAN
AUTOON
FAN
AUTO
ON
EM. HT. HEAT OFF COOL

13
14
PROGRAMMING YOUR THERMOSTAT
EM. HT. HEAT OFF COOL
EM. HT. HEAT OFF COOL
EM. HT. HEAT OFF COOL
Now, while you enjoy precision
temperature control, read on to
learn about the operating flexibility
that makes this thermostat THE
SMART CHOICE.
OPERATING YOUR THERMOSTAT
TEMPORARILY CHANGING
THE PROGRAM
These features let you tailor the
program for those times when
someone comes home early, or
you’re staying up late, or you plan
to be out for the evening.
SKIP
NEXT
PERIOD
TUE
LEAVE RETURN
PM
TUE
WAKE TEMPORARY
PM
Press and release. The name of the
period to be skipped will flash in the
display until the next regularly
scheduled period starts.
Press and release. The display will
show the name of the previous
period and flash TEMPORARY until
the next regularly scheduled periods
starts.
HEAT: The thermostat controls your
heating system.
OFF: Both your heating and cooling
systems are off.
COOL: The thermostat controls your
cooling system.
You have finished programming your
thermostat.
CHANGE
TO LAST
PERIOD