Honeywell T8624D User manual

® U.S. Registered Trademark
Copyright © 2002 Honeywell • • All Rights Reserved
INSTALLATION INSTRUCTIONS
69-1412-1
T8624D Chronotherm®IV
Deluxe Programmable
Multistage Thermostats
APPLICATION
The T8624D Chronotherm® IV Deluxe Programmable
Multistage Thermostats provides electronic control of 24
Vac single-zone multistage systems.
Refer to Table 1 for a general description of the
thermostats. All T8624 thermostats require a common
wire to supply power.
Table 1. Description of T8624 Thermostats.
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. Dispose of properly.
Contact your local waste management authority
for instructions regarding recycling and the
proper disposal of the old control.
INSTALLATION
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 1.5m (5 ft) 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.
T8624 Changeover System Selection
Fan
Selection Comments
D Automatic Heat-Off-Cool-Auto On-Auto System and fan selections are done by keyboard.

T8624D CHRONOTHERM®IV DELUXE PROGRAMMABLE MULTISTAGE THERMOSTATS
69-1412—1 2
Wallplate Installation
The thermostat can be mounted horizontally on the wall
or on a 2 in. x 4 in. (50.8 mm x 101.6 mm) wiring box.
Position wallplate horizontally on the wall or on a
2 in. x 4 in. (50.8 mm x 101.6) mm wiring box.
Fig. 1. Typical location of thermostat.
1. Position and level the wallplate (for appearance
only). The thermostat will function 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 inch (76 mm) holes in the wall (if drywall) as
marked. For firmer material such as plaster, drill
two 7/32 inch (5.56 mm) holes. Gently tap anchors
(provided) into the drilled holes until flush with the
wall.
4. Position the wallplate over the holes, pulling wires
through the wiring opening.
5. Loosely insert the mounting screws into the holes.
6. Tighten mounting screws.
Fig. 2. Mounting the wallplate.
WIRING
All wiring must comply with local electrical codes and
ordinances. Refer to Fig. 3 for typical hookup. A letter
code is located near each terminal for identification.
CAUTION
Electrical Shock Hazard.
Can cause electrical shock or equipment
damage.
Disconnect power before beginning wiring.
1. Loosen the terminal screws on the wallplate and
connect the system wires. See Fig. 4.
IMPORTANT
Use 18 gauge, color-coded thermostat cable for
proper wiring.
2. Securely tighten each terminal screw.
3. Push excess wire back into the hole.
4. Plug the hole with nonflammable insulation to pre-
vent drafts from affecting the thermostat.
1.5 METERS
(5 FEET)
YES NO
NO
NO
M10856
WIRES
THROUGH WALL
WALL
MOUNTING
HOLES
M15044
MOUNTING
SCREWS
WALL
ANCHORS (2)

T8624D CHRONOTHERM®IV DELUXE PROGRAMMABLE MULTISTAGE THERMOSTATS
3 69-1412—1
Fig. 3. Typical hookup of T8624D
in a heat pump system.
Fig. 4. Correct wiring technique.
Mounting Thermostat
1. Engage tabs at the top of the thermostat and wall-
plate. See Fig. 5.
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. 5. Mounting thermostat on wallplate.
W2
L1
(HOT)
L2
M11309
FAN
RELAY
Y1 G C
THERMOSTAT
RC
HEAT
RELAY
1
RW1
L1
(HOT)
L2
COMPRESSOR
CONTACTOR 1
Y2
COMPRESSOR
CONTACTOR 2
HEATING
TRANSFORMER
COOLING
TRANSFORMER
HEAT
RELAY
2
OTOTB
HEAT
DAMPER
OUTDOOR
SENSOR
COOL
DAMPER
O
2
2
3
3
3
1POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
JUMPER RC TERMINAL TOR TERMINAL WHEN INSTALLED ON A
ONE TRANSFORMER SYSTEM.
CAN BE USED FOR CHANGEOVER VALVE ON HEAT
PUMP SYSTEMS.
1
1
M4826
FOR WRAPAROUND
INSERTION STRIP
7/16 IN. (11 MM).
FOR STRAIGHT INSERTION
STRIP 5/16 IN. (8 MM).
M14628
PRESS LOWER
EDGE OF CASE
TO LATCH.
ENGAGE TABS
AT TOP OF
THERMOSTAT
AND WALLPLATE.
A.
B.

T8624D CHRONOTHERM®IV DELUXE PROGRAMMABLE MULTISTAGE THERMOSTATS
69-1412—1 4
Fig. 6. T8624D key locations and descriptions.
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 System Test,
• display outdoor temperature (select models),
• set the system operation,
• set the fan operation.
See Fig. 6 for the location of the keys.
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. 7. 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. 7. T8624D System and Fan key locations.
NOTE: Always press the keys with your fingertip or
similar blunt tool. Sharp instruments like a pen
or pencil point can damage the keyboard.
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
Owners Guide, form number 69-0940, for complete
instructions on changing the program.
Table 2. Default Program Settings.
M14624
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 OPTIONS
DISPLAY INFORMATION
SUCH AS PRESENT
SETTINGS AND OUTDOOR
TEMPERATURE
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
INCREASE TIME SETTING
OR SCROLL FORWARD
THROUGH 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
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
Hold Temp
Run
Program
Copy
Daylight
Time
Set Current
Day/Time
System Fan
Time Set Program
Day System
Fan
Wake Leave Return Sleep
Heat/Cool
Settings

T8624D CHRONOTHERM®IV DELUXE PROGRAMMABLE MULTISTAGE THERMOSTATS
5 69-1412—1
INSTALLER SETUP
NOTE: For most applications, the thermostat factory-
settings will not need to be changed. Review
the factory settings in Table 2 and if no changes
are necessary, go to the Installer System Test
section.
The Installer Setup is used to customize the thermostat
to specific systems. Some of the options include
temperature display, changeover, and outdoor
temperature display. Installer Setup numbers are listed in
Table 3. The table includes all the configuration options
and the factory settings for the T8624.
A combination of key presses are required to use the
Installer Setup feature.
— To enter the installer setup, press and hold the
information ikey with the increase !and
decrease "keys until the first number is displayed.
All display segments appear for approximately three
seconds before the number is displayed. See Fig. 8
and 9.
— To advance to the next Installer Setup, press the
Time ∆key.
— To change a setting, use the increase !or
decrease " key.
— To scroll the Installer Setup numbers backward, press
the Time ∇key.
— To exit the Installer Setup, press Run Program.
Fig. 8. Display of all LCD segments..
Fig. 9. Display of Installer Setup number and setting.
IMPORTANT
Only configurable numbers are shown on the
device. Example: If thermostat does not have a
System key, Installer Setup Number 12 will not
be displayed. Review Table 3 factory settings
and mark any desired changes in the Actual
Setting column. When Installer Setup is
complete, review the settings to confirm that
they match the system.
M14559
Aux Ht
Set Day/TimeSet Program
Mon
Wake Leave Return Sleep
Ou
t
door
Room
Filter
Wait
F
Fan
Em H
eat
On
A
u
t
o
O
f
f
C
oo
l
A
u
t
o
AM
PM
Hold for
Heat Cool
Repl Batt
Recovery
DST
Tue Wed Thu 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)
Table 3. Thermostat Installer Setup Options.
Select
Installer Setup
Number (Press
Time ∆key to
change)
Factory Setting
Other Choices
(Press !or "key to change)
Actual
SettingDisplay Description Display Description
Not Used. 1 — — — — —
Fan operation. 2 0 Conventional
applications where
equipment controls
fan operation in
heat mode
1 Heat pump and electric heat
applications where
thermostat controls fan
operation in heat mode
Not Used. 3 — — — — —
Heating cycle
rate.a
4 6 Stage 1 — 6—6 cph is fixed for stage 1.
5 Stage 2 3 or 9 3—3 cph
6—6 cph factory setting for
all stages of system
9—9 cph used for electric
heat
Not Used. 6 thru 11 — — — — —
System setting
adjustment
12 1 Manual
changeover
0 or 2 0—Auto changeover
2—Fixed auto changeover
a The cycle rate for the last stage of heat is adjustable with 6 cph as the factory setting.

T8624D CHRONOTHERM®IV DELUXE PROGRAMMABLE MULTISTAGE THERMOSTATS
69-1412—1 6
Adaptive
Intelligent
Recovery™
control.
13 0 Adaptive Intelligent
Recovery™
control is activated
(system starts
early so setpoint is
reached by start of
program period).
1 Conventional recovery
(system starts recovery at
programmed time).
—
Degree
temperature
display
14 0 Temperature is
displayed in °F
1 Temperature is displayed
in °C
Not Used. 15 — — — — —
Clock format. 16 0 12-hour clock
format.
1 24-hour clock format.
Not Used. 17 thru 18 — — — — —
Extended fan
operation in
heating
19 0 No extended fan
operation after the
call for heat ends.
1 Fan operation is extended
90 seconds after the call for
heat ends.
Extended fan
operation in
cooling
20 0 No extended fan
operation after the
call for cool ends.
1 Fan operation is extended
90 seconds after the call for
cool ends.
Not Used. 21 thru 23 — — — — —
Outdoor
temperature
display (models
with OT
terminals).
24 0 No outdoor
temperature is
displayed.
1 Outdoor temperature is
displayed. Needs a
C7089B1000 Outdoor
Temperature Sensor to
operate.
Not Used. 25 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 5 5 minutes
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.
Temperature
range stops in
heating.
34 90 Highest setpoint
setting for heating.
40 to 89 Temperature range (1°F
increments) of heating
setpoint settings.
Temperature
range stops in
cooling.
35 45 Lowest setpoint
setting for cooling.
46 to 99 Temperature range (1°F
increments) of cooling
setpoint settings
Not Used. 36 — — — — —
Table 3. Thermostat Installer Setup Options. (Continued)
Select
Installer Setup
Number (Press
Time ∆key to
change)
Factory Setting
Other Choices
(Press !or "key to change)
Actual
SettingDisplay Description Display Description

T8624D CHRONOTHERM®IV DELUXE PROGRAMMABLE MULTISTAGE THERMOSTATS
7 69-1412—1
IMPORTANT
Review the settings to confirm that they match
the system. Press Run Program to exit the
Installer Setup. The thermostat has saved the
Installer Setup changes and initiated a reset in
order to operate using the new settings. Be sure
to set the current day and time immediately.
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 ∆or Time ∇until the current time is dis-
played.
NOTE: Tapping the Set Current Day/Time changes the
time in one-hour increments.
Temperature
display
adjustment.
37 0 No 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.
43 2 30 days (System
run time).
0, 1, 3, 4 0 – Off
1 – 10 days
3 – 60 days
4 – 120 days
(Time counted when heat,
cool or fan is running.)
Humidifier Pad
Monitor.
44 0 Off 1, 2, 3 1 – 90 days
2 – 180 days
3 – 365 days
(Time counted by calendar
days in heat mode.)
Ultraviolet Air
Treatment (UV)
System Lamp
Monitor.
45 0 Off 1 1 – 365 days
(Time counted by calendar
days in any mode.)
Table 3. Thermostat Installer Setup Options. (Continued)
Select
Installer Setup
Number (Press
Time ∆key to
change)
Factory Setting
Other Choices
(Press !or "key to change)
Actual
SettingDisplay Description Display Description
M14619
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
M14620
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
M14621
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

T8624D CHRONOTHERM®IV DELUXE PROGRAMMABLE MULTISTAGE THERMOSTATS
69-1412—1 8
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. Reset the timer by pressing the ikey until the
expired timer is displayed.
2. Press the Time skey 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 i key three or four
times. If more than one timer is active, all active
timers show sequentially when pressing the
i key several times.
INSTALLER SYSTEM TEST
Use the Installer System Test to check the thermostat
operation. Refer to Table 4 for a list of the available
system tests.
To start the system test:
CAUTION
The minimum off time for compressors is
bypassed during the Installer System Test.
Equipment damage can occur if the compressor
is cycled too quickly.
Press and hold the increase !and decrease "keys at
the same time until 10 appears. All segments of the
display will be displayed before the 10 appears.
See Fig. 10 and 11.
Table 4. Tests Available In Installer System Test.
Fig. 10. Display of all the segments of the LCD.
Fig. 11. Display of test number.
Refer to Table 5 for the directions and results of the
specific tests.
Press Time ∆to advance to the next test and Time ∇to
go back to the previous test. Press Run Program to exit
the system test
M14622
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
M14623
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
M20243
Filter Days
M20244
Filter Days
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.
M14559
Aux Ht
Set Day/TimeSet Program
Mon
Wake Leave Return Sleep
Ou
t
door
Room
Filter
Wait
F
Fan
Em H
eat
On
A
u
t
o
O
f
f
C
oo
l
A
u
t
o
AM
PM
Hold for
Heat Cool
Repl Batt
Recovery
DST
Tue Wed Thu Fri Sat Sun
Days
Temporary Setting
Em Ht
M14612

T8624D CHRONOTHERM®IV DELUXE PROGRAMMABLE MULTISTAGE THERMOSTATS
9 69-1412—1
Table 5. Installer System Test Options.
NOTE: Press any key and the displayed numbers will change. Press Time ∇to go to the previous test and Time ∆to
go to the next test. The Run Program key will not exit this test. Press Time ∆or Time ∇and then the
Run Program key to exit.
Keys to
Press
Test
Number Description
Heating Equipment System Test
Time ∆10 Enter heating equipment System Test.
!11 Stage-one heat comes on. The system fan is also energized.
!12 Stage-two heat comes on. Stage-one heat and system fan remain on.
"11 Stage-two heat turns off.
"10 Stage-one heat and system fan turn off.
Cooling Equipment System Test
Time ∆30 Change from heating to cooling equipment System Test.
!31 Stage-one cool and system fan come on.
"32 Stage-two cool comes on. Stage-one cool and system fan remain on.
"31 Stage-two cool turns off.
"30 Stage-one cool and system fan turn off.
Fan Equipment System Test
Time ∆40 Change from cooling to fan equipment System Test.
!41 Fan comes on.
"40 Fan turns off.
Key Operation System Test
Time ∆60 Change from fan to key operation System Test.

T8624D CHRONOTHERM®IV DELUXE PROGRAMMABLE MULTISTAGE THERMOSTATS
69-1412—1 10
THERMOSTAT INFORMATION
1. Press the Time ∆key to access the thermostat
information.
2. Press the increase !key to display the production
date code. The first two large digits are the month
and the third digit is the last digit of the year (Exam-
ple: 027 = February 1997).
3. Press the increase !key again to display the soft-
ware identification code. (Example: 02 = software
ID code 2)
4. Press the increase !key again to display the soft-
ware revision number (Example: 001 = Revision
number 1).
5. Press the increase !key 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.
CHECKOUT
Outdoor Temperature Sensor
(Select Models)
Allow the outdoor temperature sensor to absorb the
outdoor air for a minimum of five minutes before taking a
reading.
M14613
M14614
M14615
M14616
M14617