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T451A, T651A, T694A,B,D,F  
Light Duty  
LineVoltage Thermostats  
T451, T651, T694 Thermostats provide on-off  
control of valves, fans, motors, contactors, electric  
heat elements, duct furnaces and fan coil units in  
heating/cooling systems. Switching subbases pro-  
vide manual control of heating, cooling and fan.  
T451A,  
T651A  
T694B,D,F  
T694A  
T451A provides heating control only.  
 Thermostats use spst or spdt snap switches activated  
by bimetal sensor.  
T651A provides heating and cooling control.  
T451A/T651A mount on standard vertical or horizon-  
tal junction box.  
T694A,B,D,Fsuppliedwithswitchingsubbasetopro-  
vide manual control of heating, cooling and fan.  
Optionsincludeadjustablerangestops,lockingcover,  
concealedsetpoint, lockingsetpoint, positiveoffcon-  
trol, cover thermometer.  
Q473A,B switching subbase available for T451A/  
T651A.  
Automatic cooling anticipator for 120, 208, 240 and  
277 Vac.  
CONTENTS  
Specifications ................................................. 2  
Ordering Information ..................................... 2  
Installation ..................................................... 4  
Checkout......................................................... 7  
J. H. • Rev. 9- 92 • ©Honeywell Inc. 1992 • Form Number 63-2051
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T451A, T651A, T694A,B,D,F  
SPECIFICATIONS • ORDERING INFORMATION  
Specifications  
Automatic cooling anticipator for 120, 208, 240 and  
SUPER TRADELINE MODEL  
277 Vac.  
TRADELINE models are selected and packaged to provide  
ease of stocking, ease of handling and maximum replace-  
ment value. TRADELINE model specifications are the  
same as those of standard models except as noted below.  
Vertical faceplate with Fahrenheit scale and ther-  
mometer.  
Horizontal faceplate with Fahrenheit scale and ther-  
mometer.  
Blank vertical faceplate.  
Blank horizontal faceplate.  
Wallplate.  
Adjustable range stops.  
Locking cover screw.  
SUPER TRADELINE MODEL AVAILABLE:  
T651A2028 Light Duty Line Voltage Thermostat.  
FEATURES:  
Temperature scale range 35° F to 95° F.  
Spdtswitchbreaksheatingcontactsandmakescooling  
contacts on temperature rise.  
STANDARD MODELS:  
Model  
Number  
T451A2007a Heating only.  
Changeover  
Application  
System Switch  
Switch  
Fan Switch  
T451A2015  
T651A2028a Heating/cooling.  
Heating only with positive OFF.  
T694A2002  
T694B2001  
T694D2009  
Heating/cooling. OFF position breaks  
fan circuit.  
ON-OFF  
HI-MEDIUM-LO  
Heating/cooling. OFF position breaks  
cooling and fan circuits.  
ON-OFF  
ON-OFF  
HEAT-COOL HI-MEDIUM-LO  
HEAT-COOL HI-MEDIUM-LO  
Heating/cooling. Heating circuits isolated  
from cooling circuits. OFF position  
breaks all control circuits except heat.  
T694F2007  
Heating/cooling. Heating circuits isolated  
from cooling circuits. OFF position breaks  
all power to fan and thermostat.  
ON-OFF  
HEAT-COOL HI-MEDIUM-LO  
a
With thermometer.  
Ordering Information  
When purchasing replacement and modernization products from your TRADELINE® wholesaler or your distributor, refer to the  
TRADELINE Catalog or price sheets for complete ordering number, or specify—  
1
2
3
. Order number.  
. Accessories, if desired.  
. Order additional components and system accessories separately.  
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 Honeywell Home and Building Control Sales Office (check white pages of your phone directory).  
2
. Home and Building Control Customer Satisfaction  
Honeywell Inc., 1885 Douglas Drive North  
Golden Valley, MN 55422-4386 (612) 951-1000  
In Canada—Honeywell Limited/Honeywell Limitee, 740 Ellesmere Road, Scarborough, Ontario M1P 2V9, 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.  
2
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T451A, T651A, T694A,B,D,F  
SPECIFICATIONS  
ELECTRICAL RATINGS (A):  
FINISH: Brushed champagne gold and dark pewter face-  
plate; beige and brown case.  
Voltage (Vac)  
208/240/277  
4a  
24  
120  
UNDERWRITERS LABORATORIES INC.: Listed.  
Full Load  
8
ACCESSORIES:  
Locked Rotor  
48  
Q473A2006 Switching Subbase: Use with T651A for  
HEAT-OFF-COOL manual system switching.  
Q473B2005 Switching Subbase: Use with T451A/  
T652A for AUTO/OFF switching in heating only or  
cooling only applications.  
a
Wider temperature differential ranges can occur when  
used in cooling applications with current draws that are  
more than four amps. If a wider differential range is  
unacceptable, use a T6051 Heavy Duty Line Voltage  
Thermostat for a smaller differential range.  
2
20124A Faceplate vertical, Fahrenheit scale, with  
thermometer.a  
Pilot Duty: 125 VA.  
.2A Resistive: heating contacts only.  
220124B Faceplate vertical, Celsius scale, with ther-  
mometer.  
7
2
20124C Faceplate, horizontal, Fahrenheit scale, with  
TEMPERATURE SETTING RANGE: 35° F to 95° F [2° C  
to 35° C] (with range stops removed).  
thermometer.a  
220124D Faceplate, horizontal, Celsius scale, with ther-  
mometer.  
STORAGE TEMPERATURE: -40° F to 150° F [-40° C to  
220125A Faceplate, horizontal, Fahrenheit scale, with-  
out thermometer.  
66° C].  
2
20125B Faceplate, vertical, Fahrenheit scale, without  
thermometer.  
FIXED DIFFERENTIAL: 2° F [1° C].  
220125C Faceplate, horizontal, Celsius scale, without  
thermometer.  
SWITCHING ACTION:  
T451: Spst. Contacts make on temperature fall.  
T651: Spdt. Heating contacts break and cooling contacts  
make on temperature rise.  
T694: Spdt. Heating contacts break and cooling contacts  
make on temperature rise.  
220125D Faceplate, vertical, Celsius scale, without ther-  
mometer.  
220126AFaceplate, horizontal, blank(concealedsetpoint,  
without thermometer).a  
220126B Faceplate, vertical, blank (concealed setpoint,  
without thermometer).a  
FIELD WIRING CONNECTIONS: No. 10 screw terminals  
on T451A/T651A; color-coded leads on T694 models.  
220213 Wallplate, covers old T451A/T651A wall marks  
when installing new T451A/T651A.a  
199242 Wallplate, covers old T694 wall marks when  
DIMENSIONS: See Figs. 1 and 2.  
installing new T694.  
a
Supplied with SUPER TRADELINE model T651A.  
Fig. 1—T451A, T651A mounting dimensions in in. [mm].  
1
5  
9  
16  
[14]  
1
3
2  
[
35]  
60  
70  
5
0
80  
90  
4
0
1
7  
9  
3
4
3
2
32  
[
114]  
[83]  
3


F
1
COOL HEAT COM  
4
40  
50 60 70 80 90  
[45]  
1  
8  
1

1
3  
6  
1
2
1
15  
17  
32  
8

1
1
6  
[37]  
[
70]  
[22]  
[
24]  
[14]  
1
3  
1
[
1
6  
M6130  
48]  
3
63-2051—4  
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T451A, T651A, T694A,B,D,F  
INSTALLATION  
Fig. 2—T694A,B,D,F mounting dimensions in in. [mm].  
7


1
8
[
48]  
SYSTEM  
ON  
60  
70  
5
0
80  
90  
OFF  
4
0
7

HEAT  
COOL  
4
3 9  
3  
76]  
8
3
2  
[
[
124]  
[
83]  
F
FAN  
HI  
MED  
LOW  
2
9  
2  
4
15  
2  
35]  
3
3
9  
1
[
125 ]  
[
16  
40]  
[
(T694B SHOWN)  
1
3  
2  
1
3
M6129  
[
36]  
Installation  
Do not install the thermostat where it may be affected by:  
• drafts, or dead spots behind doors and in corners.  
WARNING  
!
hot or cold air from ducts.  
Do not use on electric heat. Possible fire hazard if  
T694A,B,D used on electric heat. T694F can be  
used on electric heat.  
radiant heat from sun or appliances.  
concealed pipes and chimneys.  
unheated (uncooled) areas behind the thermostat,  
such as an outside wall.  
WHEN INSTALLING THIS PRODUCT…  
. Read these instructions carefully. Failure to follow  
them could damage the product or cause a hazardous  
1
WIRING AND MOUNTING  
Disconnect power supply before making wiring connec-  
tions to prevent electrical shock and equipment damage.  
All wiring must comply with applicable electrical codes,  
ordinances and regulations. Use copper wire only. Make  
sure that thermostat electrical rating is sufficient for current  
requirements of controlled equipment, and that listed volt-  
age matches power supply.  
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 installation is complete, check out product op-  
eration as provided in these instructions.  
T451A/T651A THERMOSTATS (Fig. 3)  
T451A/T651A Thermostats mount vertically on a 2 x 4  
in. or 4 x 4 in. junction box. See Fig. 3. Use 2 x 4 in. cover  
plate with 4 x 4 in. junction. For horizontal mounting, the  
appropriate horizontal faceplate is required. Horizontal  
with thermometer and horizontal blank faceplates are  
packaged with the T651A2028 SUPER TRADELINE  
model. For additional faceplates or T451 applications, see  
Accessories. When replacing old style T451A/T651A, use  
a wallplate to cover previous wall marks. This wallplate is  
packaged with the T651A2028 SUPER TRADELINE  
model. For T451 applications, see Accessories.  
CAUTION  
!
Disconnect power supply before making wiring  
connections to prevent electrical shock and equip-  
ment damage. Use copper wire only.  
LOCATION  
Select the same location as control to be replaced, or  
select a new location about 5 ft. [1.5 m] above the floor, on  
an inside wall where there is good air circulation at average  
room temperature.  
4
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T451A, T651A, T694A,B,D,F  
INSTALLATION  
1
. Before mounting thermostat, connect system wiring  
2. Remove thermostat cover assembly. Attach thermo-  
stat to junction box with two screws provided. Replace  
thermostat cover assembly.  
to proper terminals at rear of thermostat. Follow equip-  
ment manufacturer instructions or refer to Fig. 4 for  
typical system hookup.  
2
. Remove cover assembly from thermostat. Attach  
thermostat to junction box with two screws provided. Re-  
place cover assembly. See Fig. 3.  
Fig. 4—T652A in heating-cooling system.  
3. Use 1/16 hex Allen wrench to install Allen locking  
cover screw.  
Fig. 3—Mounting T451A/T651A.  
2
20213 WALLPLATE  
ACCESSORY  
(
OPTIONAL)  
(
COVERS OLD T651A  
WALL MARKS WHEN  
INSTALLING NEW T651A)  
Fig. 5—Mounting T694A,B,D,F.  
TABS HOLD  
COVER ASSEMBLY  
AT TOP (SNAP  
IN AT BOTTOM)  
MOUNTING  
SCREWS (2)  
COVER PLATE  
4
x4 JUNCTION  
BOX  
70  
80  
60  
90  
TABS HOLD  
COVER ASSEMBLY  
AT TOP (SNAP  
IN AT BOTTOM)  
USE 2x4  
50  
40  
JUNCTION  
BOX  
F
ON  
SYSTEM  
MOUNTING  
SCREWS (2)  
40  
50 60 70 80 90  
OFF  
HEAT  
COOL  
HI  
FAN  
M6131  
MED  
LOW  
USE 2x4 OR 4x4  
JUNCTION BOX  
70  
8
0
60  
9
0
T694A,B,D,F THERMOSTATS (Fig. 5)  
50  
All T694A,B,D,F Thermostats mount vertically on a 2 x  
in. or 4 x 4 in. junction box. See Fig. 5. Use 2 x 4 in. cover  
40  
F
4
(T694B SHOWN)  
plate with 4 x 4 in. junction box.  
. Before mounting, connect system wiring to proper  
1
color-coded leads at rear of thermostat. Follow equipment  
manufacturer instructions or refer to Figs. 6-9 for typical  
system hookups.  
M6135  
5
63-2051—4  
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T451A, T651A, T694A,B,D,F  
INSTALLATION  
Fig. 6—T694A in heating-cooling system with  
independent valve and fan circuits.  
Fig. 8—T694D with isolated switching for heating  
and cooling.  
Fig. 7—T694B connected for positive-off switch-  
ing in COOL position.  
Fig. 9—T694F with positive-off position.  
6
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T451A, T651A, T694A,B,D,F  
CHECKOUT  
Checkout  
After the thermostat is wired and mounted, perform the  
following system checkout procedure.  
T694  
NOTE: System switch must be in ON position to check  
out system.  
T451/T651  
IN HEATING APPLICATION:  
1
. Close disconnect switch (if used).  
1. Close the disconnect switch (if used) and press  
HEAT switch; adjust setpoint above room temperature  
and check that heating system turns on.  
2. Adjust setpoint below room temperature and check  
that heating system turns off.  
3. Press COOL switch; adjust setpoint below room  
temperature. Check that cooling system turns on and fan  
runs continuously.  
2. Adjust setpoint above room temperature and check  
that heating system turns on.  
. Adjust setpoint below room temperature and check  
that heating system turns off.  
. Adjust thermostat for desired room temperature.  
3
4
IN COOLING APPLICATION:  
1
. Close disconnect switch (if used).  
4
. Press fan LO, MED, HI switches and check that fan  
control operates properly.  
. Adjust setpoint above room temperature and check  
that cooling system turns off. Fan operates continuously.  
. Adjust thermostat for desired room temperature.  
2. Adjust setpoint below room temperature and check  
that cooling system turns on.  
. Adjust setpoint above from temperature and check  
that cooling system turns off.  
. Adjust thermostat for desired room temperature.  
5
3
6
4
If questions arise regarding this product, contact your  
distributor or local Honeywell representative.  
NOTE: Wider temperature differential ranges can occur  
when used in cooling applications with current draws  
that are more than four amps. If a wider differential  
range is unacceptable, use a T6051 Heavy Duty Line  
Voltage Thermostat for a smaller differential range.  
7
63-2051—4  
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Home and Building Control  
Honeywell Inc.  
Home and Building Control  
Honeywell Limited—Honeywell Limitée  
740 Ellesmere Road  
Helping You Control Your World  
1
985 Douglas Drive North  
Golden Valley, MN 55422  
Scarborough, Ontario  
M1P 2V9  
QUALITY IS  
KEY  
Printed in U.S.A.