Honeywell T8624D User Manual
T8624D Chronotherm
Programmable Thermostat
APPLICATION
The T8624D Chronotherm® IV Deluxe Programmable
Thermostat provides electronic control of 24 Vac multistage
heating and cooling systems.
®
IV Deluxe
PRODUCT DATA
• Models available with outdoor temperature sensor
capability for homeowner convenience. The sensor is
also more accurate than a thermometer.
• Configurable features allows one model to be used to
replace many different models (less inventory, no
longer need to carry separate models to get these
features).
— °F or °C temperature display;
— automatic or manual changeover;
— electric or conventional heat fan operation;
— adjustable heating cycle rate.
• Minimum off time for cooling compressors and heat
pumps protects the equipment and extends the
equipment life.
• Easy installation, setup and system test saves
installer time and increases productivity.
• System test simplifies troubleshooting and saves time
by overriding the time delays.
• Adaptive Intelligent Recovery® control brings the
room temperature to temperature setpoint at the
programmed time, maximizing comfort and energy
savings.
• Setpoints are permanently held in memory (no
batteries used) and retained during power outages for
increased installer and homeowner convenience.
• Universal Versaguard™ Thermostat guards available
for added security.
FEATURES
• Full seven-day program capability; different schedules
and temperature setpoints may be selected for
everyday to match the homeowner’s flexible schedule.
• Copy key makes programming easier and faster for
the installer and homeowner.
• Daylight Savings Time (DST) key for quick change in
and out of Daylight Savings Time.
• Models available with programmable fan operation for
added homeowner comfort.
• Easy temporary temperature setpoint changes for
current period, vacation hold (1 to 255 days) or
indefinite hold adds to the homeowner comfort and
energy savings.
• Most frequently used keys are located by the Liquid
Crystal Display (LCD) for quick and easy access to
information.
• Attractive styling complements any decor to the
homeowner’s delight.
• Back lighting the large display makes the LCD very
easy to read.
® U.S. Registered Trademark
Copyright © 1997 Honeywell Inc. • All Rights Reserved
Contents
General ............................................................................... 1
Features .............................................................................. 1
Specifications ...................................................................... 2
Ordering Information ........................................................... 2
Installation ........................................................................... 3
Wiring .................................................................................. 4
Settings ............................................................................... 6
Installer Setup ..................................................................... 7
Installer System Test ........................................................... 10
Programming....................................................................... 12
Operation ............................................................................ 16
Troubleshooting Guide ........................................................ 18
Cross Reference ................................................................. 19
Wiring Diagram ................................................................... 20
68-0166-1
T8624D CHRONOTHERM® IV DELUXE PROGRAMMABLE THERMOSTAT
SPECIFICATIONS
Important
Thermostat Model
T8624D Thermostats provide features listed in Table 1.
Changeover
Electrical Rating (Nominal Range):
Batteries:
No batteries required.
Loss of Power:
The thermostat will maintain programmed times and
temperatures for the life of the product. The clock and day
information is retained for a minimum of thirty minutes.
The specifications given in this publication do not
include normal manufacturing tolerances. Therefore,
this unit might not exactly match the listed
specifications. This product is tested and calibrated
under closely controlled conditions, and some minor
differences in performance can be expected if those
conditions are changed.
Table 1. Thermostat Features.
System
Selection
Automatic Heat-Off-
Cool-Auto
24 Vac, 50/60 Hz.
20 to 30 Vac, 50/60 Hz.
Fan
Selection Comments
On-Auto System and fan
selections are done
by keyboard.
Temperature:
Ratings:
Operating Ambient: 40°F to 110°F (4°C to 43°C).
Shipping: -30°F to +150°F (-34°C to +65°C).
Display Accuracy:
±1°F (±0.5°C).
Setpoint:
Range:
Heating: 40°F to 90°F (7°C to 31°C)
Cooling: 48°F to 99°F (9°C to 37°C).
Differential: 3°F (1.5°C).
Default Settings: see Table 3.
Table 3. Default Setpoints.
Period Time
Wake 6:00 AM 70°F
Leave 8:00 AM 62°F
Return 6:00 PM 70°F
Sleep 10:00 PM 62°F
Minimum Stage Operation Time:
Minimum On (Heat and Cool) (select models): factory
setting 2 minutes; option 0 minutes.
Minimum Off (Cool and Heat Pump): factory setting
2 minutes; option 0 minutes.
Heat
Setpoint
(21°C)
(16.5°C)
(21°C)
(16.5°C)
Cool
Setpoint
78°F
(25.5°C)
85°F
(29.5°C)
78°F
(25.5°C)
82°F
(28°C)
Fan
Setting
Auto
Auto
Auto
Auto
System Current Load Ratings:
6 VA maximum at 30 Vac, 50/60 Hz.
Output Relay Draw:
See Table 2.
Table 2. Maximum Amps at 30 Vac.
Relay Running (A) Inrush (A)
Fan 0.5 2.5
Heat (all stages) 1.5 3.5
Cool (all stages) 1.5 7.5
Humidity Ratings:
5% to 90% RH, noncondensing.
Clock Accuracy:
+1 minute per month.
Finish:
Taupe or Premier White® color.
ORDERING INFORMATION
When purchasing replacement and modernization products from your TRADELINE® wholesaler or distributor, refer to the
TRADELINE® Catalog or price sheets for complete ordering number.
If you have additional questions, need further information, or would like to comment on our products or services, please write or
phone:
1. Your local Home and Building Control Sales Office (check white pages of your phone directory).
2. Home and Building Control Customer Relations
Honeywell, 1885 Douglas Drive North
Minneapolis, Minnesota 55422-4386
In Canada—Honeywell Limited/Honeywell Limitée, 35 Dynamic Drive, Scarborough, Ontario M1V 4Z9.
International Sales and Service Offices in all principal cities of the world. Manufacturing in Australia, Canada, Finland, France,
Germany, Japan, Mexico, Netherlands, Spain, Taiwan, United Kingdom, U.S.A.
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2
T8624D CHRONOTHERM® IV DELUXE PROGRAMMABLE THERMOSTAT
Dimensions:
See Fig. 1.
3-5/8 (92)
6-1/16 (154)
2-3/4 (70)
3/8 (10)
1-13/16
(46)
3-3/4
(95)
3-1/2
(89)
1-9/16
1/2
(13)
(40)
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 5 ft (1.5m) above the floor in an
area with good air circulation at average temperature.
See Fig. 2.
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.
M10359
Fig. 1. Dimensions of thermostat in in. (mm).
Mounting Means:
The thermostat mounts on a wallplate. The wallplate mounts
horizontally on a wall or outlet box with two no. 6 x 32 screws
(included).
Accessories:
C7089B Outdoor Temperature Sensors (69-1020).
Universal Versaguard™ Thermostat guards.
RECYCLING NOTICE
If this control is replacing a control that contains
mercury in a sealed tube, do
control in the trash.
Contact your local waste management authority for
instructions regarding recycling and the proper
disposal of the old thermostat.
not
place your old
Wallplate Installation
The thermostat can be mounted horizontally on the wall or on
a 2 in. x 4 in. wiring box. Position wallplate horizontally on the
wall or on a 2 in. x 4 in. wiring box.
1. Position and level the wallplate (for appearance only).
The thermostat will function properly even when
not level.
2. Use a pencil to mark the mounting holes. See Fig. 3.
3. Remove the wallplate from the wall and drill two
3/16 inch holes in the wall (if drywall) as marked. For
firmer material such as plaster, drill two 7/32 inch 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.
3
68-0166—1
T8624D CHRONOTHERM® IV DELUXE PROGRAMMABLE THERMOSTAT
YES
NO
NO
5 FEET
[1.5 METERS]
NO
Fig. 2. Typical location of thermostat.
M10106
WALL
ANCHORS
(2)
WALL
WIRES
THROUGH WALL
Fig. 3. Mounting the wallplate.
MOUNTING
HOLES
MOUNTING
SCREWS
M10822
WIRING
All wiring must comply with local electrical codes and
ordinances. Follow equipment manufacturer wiring
instructions when available. Refer to Fig. 14 for typical
hookup. A letter code is located near each terminal for
identification. Refer to Table 4 for terminal designations.
CAUTION
Disconnect power before wiring to prevent electrical
shock or equipment damage.
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 prevent
drafts from affecting the thermostat.
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4
T8624D CHRONOTHERM® IV DELUXE PROGRAMMABLE THERMOSTAT
Table 4. Terminal Designations and Descriptions.
Standard
Terminal
Designations
Alternate
Terminal
Designations Typical Connection Function Terminal Type
B—Heat damper or changeover valve Output 24V powered contact
CB
a
, C, X1, X2 Common Input
GF Fan relay Output 24V powered contact
ORCool damper or changeover valve Output 24V powered contact
OT, OT — Outdoor temperature sensor (C7089B) Input —
RV24V system or heating transformer Input —
RC — 24V cooling transformer Input —
W1 H1, R3 Stage 1 heating relay Output 24V powered contact
W2 H2, R4, W3, Y Stage 2 heating relay Output 24V powered contact
Y1 C1, M, Y Stage 1 compressor contactor Output 24V powered contact
Y2 C2, M, Y Stage 2 compressor contactor Output 24V powered contact
a
Some OEM models label the terminal for transformer common B.
A.
ENGAGE TABS AT TOP OF THERMOSTAT AND WALLPLATE.
FOR STRAIGHT
FOR WRAPAROUND
INSERTION STRIP
7/16 IN. (11 MM).
INSERTION STRIP
5/16 IN. (8 MM).
M4826
Fig. 4. Proper wiring technique.
Mounting Thermostat Wallplate
The thermostat mounts on the wallplate after they are
installed.
1. Engage tabs at the top of thermostat and wallplate.
See Fig. 5.
2. Press lower edge of case to latch.
NOTE: To remove the thermostat from the wall, first pull out
at the bottom of the thermostat; then remove the top.
B.
PRESS LOWER EDGE OF CASE TO LATCH.
M15043
Fig. 5. Mounting thermostat on wallplate.
5
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T8624D CHRONOTHERM® IV DELUXE PROGRAMMABLE THERMOSTAT
SETTINGS
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.
System and Fan Settings
The system default setting is Heat and the fan default setting
is Auto. Use the System and Fan keys or switches 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.
Run
Program
Hold Temp
Time Set Program
Set Current
Day/Time
Day
Daylight
Copy
Time
Heat/Cool
Settings
Leave
Wake
Return
System Fan
Sleep
M15042
System
Fan
Fig. 7. T8624D System and Fan key locations.
INCREASE TIME SETTING
OR SCROLL FORWARD
THROUGH INSTALLER SETUP
AND SYSTEM TEST
SET CURRENT
DAY AND TIME
RETURN TO
NORMAL
OPERATIONS
ENTER
INDEFINITE
OR TIMED
HOLD MODE
SET CURRENT OR
PROGRAM DAY
CHANGE BETWEEN
DAYLIGHT SAVINGS
AND STANDARD TIME
COPY ONE PROGRAMMED
DAY TO ANOTHER DAY
SET WAKE TIMES
AND SETPOINTS
Run
Program
Hold Temp
Fig. 6. T8624D key locations and descriptions.
Set Current
Day/Time
Day
Daylight
Time
SET LEAVE TIMES
AND SETPOINTS
Time Set Program
Copy
Wake
Heat/Cool
Settings
SET RETURN TIMES
AND SETPOINTS
Leave
DECREASE TIME SETTING OR SCROLL
BACKWARD THROUGH INSTALLER
SETUP AND SYSTEM TEST
INCREASE TEMPERATURE
SETTING OR SCROLL
FORWARD THROUGH
INSTALLER SETUP OPTIONS
Return Sleep
System Fan
CHANGE BETWEEN HEATING
AND COOLING SETPOINTS
DECREASE TEMPERATURE
SETTING OR SCROLL
BACKWARD THROUGH
INSTALLER SETUP OPTIONS
DISPLAY INFORMATION
SUCH AS PRESENT
SETTINGS AND OUTDOOR
TEMPERATURE
SET SLEEP
TIMES AND
SETPOINTS
SELECT FAN
OPERATION
SELECT SYSTEM
OPERATION
M10405A
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