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T921A,B,E-G Proportional  
Control Thermostats  
T921 Thermostats provide 3-wire, low voltage  
proportionalcontrolforSeries90(135ohm)valve  
motors, damper motors, and balancing relays in  
heating or cooling system applications.  
T921A  
T921B  
T921E  
T921F  
T921G  
Accessoryfaceplatesavailableforhorizontalmount-  
ing of T921A,B,E models.  
 A bellows element adjusts the potentiometer slider  
to regulate motor operation.  
COOL-HEAT changeover switch in the T921B.  
Night setback mechanism and switch in the T921E.  
 Various temperature ranges are available.  
 All models are available with a thermometer and a  
locking cover.  
A spdt (single pole double throw) Class 2 auxiliary  
switch in the T921F,G, which operates at the low  
(T921F) and high (T921G) end of the throttling  
range.  
CONTENTS  
Specifications ................................................. 2  
Ordering Information ..................................... 2  
Installation ..................................................... 4  
Setting and Adjusting ..................................... 7  
Operation ....................................................... 7  
J. D. • Rev. 1 - 94 • ©Honeywell Inc. 1994 • Form Number 60-2242 2
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T921A,B,E-G  
SPECIFICATIONS • ORDERING INFORMATION  
Specifications  
THERMOMETER: Bimetal. Scale ranges T921A only:  
45°to 75° F [7° to 24° C]. All other models: 60° to 90° F  
[16° to 32° C], 15°to 35° C [59° to 95°F]. T921A is also  
available with a blank cover and no thermometer.  
AUXILIARY SWITCH DIFFERENTIAL:  
T921F: 2° F [1° C].  
®
TRADELINE MODELS  
®
TRADELINE models are selected and packaged to  
provide ease of stocking, ease of handling and maximum  
replacement value. TRADELINE model specifications  
®
are the same as those of the standard models except as noted  
below.  
®
TRADELINE MODEL AVAILABLE:  
T921G: 1° F [0.5° C].  
T921A Thermostat for vertical or horizontal mounting.  
TEMPERATURE RANGE AND SCALE:  
THROTTLING RANGE:  
Fixed.  
56° to 84° F [13° to 29°].  
T921A: 2.5° F [1° C] midscale.  
ADDITIONAL FEATURES:  
T921B,E: 4° F [2° C].  
T921F: 6° F [3° C].  
T921G: 5° F [2.5° C].  
®
TRADELINE packed with cross-reference label  
and special TRADELINE instructions.  
®
T6051A may be used in electric heat systems.  
They all include slotted sides and an add-on faceplate  
to allow the thermostat to be mounted horizontally.  
They also include the 127246A Adapter Plate As-  
sembly for vertical mounting on a horizontal conduit  
box or for horizontal mounting on a vertical conduit  
box.  
Variable.  
T921A model available with potentiometer for 5° to  
6° F [2.5 to 3° C] throttling range.  
ELECTRICAL RATINGS:  
Voltage: 24 to 30 Vac.  
Auxiliary Switch Contact Rating (When Used For Pilot  
Duty): 100 VA at 30 Vac.  
DIMENSIONS:  
STANDARD MODEL  
Refer to Fig. 1.  
MODELS:  
ACCESSORIES (ORDER SEPARATELY):  
127246A Adapter Plate Assembly for mounting all mod-  
els vertically on a horizontal conduit box. (T921  
modelsareshippedwithafaceplateforverticalmount-  
ing.)  
T921A: Heating or cooling applications.  
T921B: Is the same as the T921A but includes a cool-  
heat changeover switch.  
T921E: Includes a switch and heater that provide a night  
setback of approximately 10° F [5.5° C].  
T921F: Includes an spdt low voltage Class 2 auxiliary  
switch that operates at the low end of the throttling  
range.  
When mounting the T921A,B,E horizontally, see  
Table 1 to order the faceplate with the appropriate  
scale. NOTE: Do not mount the T921F,G horizon-  
tally.  
T921G: Includes an spdt low voltage Class 2 auxiliary  
switch that operates at the high end of the throttling  
range.  
34297B Thermostat Guard Assembly and 138541A  
Mounting Plate.  
133722A Thermostat Guard (clear plastic cover).  
133723A Thermostat Guard (beige plastic cover).  
SETTING ADJUSTMENT RANGE:  
T921A,B,E-G: 56° to 84° F [13° to 29° C].  
T921A,B,E-G: 13° to 29° C [56° to 84° F].  
T921A: 42° to 75° F [ 5° to 24° C].  
T921A,B: 66° to 95° F [19° to 35° C].  
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
. Model number.  
. Scale range.  
. Accessories, if desired.  
If you have additional questions, need further information, or want to comment on our products or services, please write or phone:  
1
2
. You local Honeywell Home and Building Control Sales Office (check the white pages of the phone directory).  
. Home And Building Control Customer Satisfaction  
Honeywell Inc., 1885 Douglas Drive North  
Minneapolis, Minnesota 55422 1-800-468-1502  
(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.  
6
0-2242—2  
2
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T921A,B,E-G  
SPECIFICATIONS  
7
640HX Averaging Element Mounting Kit: For mount-  
ing in existing installations where access to the duct  
is impractical.  
Fig. 1—T921 approximate installation dimen-  
sions in in. [mm].  
ACCESSORY ADAPTER PLATE (127246A) FOR  
MOUNTING ON HORIZONTAL CONDUIT BOX  
SETTING  
ADJUSTMENT  
KNOB  
Q615A Enclosure: To protect the device when mounted  
outside; splash proof.  
801534 Calibration Wrench.  
HORIZONTAL CONDUIT BOX  
FOR VERTICAL  
CONDUIT BOX (2)  
1
3
07324A Bulb Holder: For mounting the bulb in a duct.  
4886A Outdoor Bulb Shield: To protect the outdoor  
bulb mounting.  
3
5
5
7
Fig. 2—T991B approximate installation  
dimensions in in. [mm].  
5
8
8
3
[
[137]  
[194]  
16  
84]  
1
1
145]  
1
6
5
[
15  
16  
[
24]  
KNOCKOUT FOR 1/2 INCH  
CONDUIT (BOTH ENDS)  
1
3
1
1
4
3
[78]  
1
4
4
[108]  
16  
2
[57]  
5
1
4
3
[84]  
5
2 [51]  
2
[57]  
16  
3
8
3
[10]  
8
1
8
3
[86]  
2
[57]  
1
2-11/16 [69] INCHES FOR  
T921F, G MODELS.  
M9107  
5
[135]  
16  
3
4
1
[
45]  
TABLE 1—ACCESSORY FACEPLATE.  
3
16  
106]  
4
[
Scale  
Part No.  
135135A  
135135B  
135135C  
135135D  
135135Ca  
5
1
4
6
5
6° to 84° F [13° to 29° C]  
3° to 29° C [56° to 84° F]  
2° to 75° F [5° to 24° C]  
6° to 95° F [19° to 35° C]  
6° to 84° F [13° to 29° C]  
5
8
5
[
143]  
7
[6]  
32  
DIAMETER (3)  
15  
16  
aBlank faceplate.  
3
[24]  
[10]  
8
1
4
32]  
DIAMETER  
1
[
REPLACEMENT PART:  
1
130224 Locking Cover Knob.  
OPTIONAL SPECIFICATION (USING THE T991B):  
Alternate proportional control similar to the T921A, but  
uses an outdoor temperature, automatic control point  
reset.  
2
T991B with 3-1/2: 1 reset and 50° to 120° F [10° to  
1
2
OUTDOOR BULB SIZE VARIES INVERSELY WITH THE RESET RATIO.  
4
9° C] temperature setting scale (when the outdoor  
bulb is at 60° F [16° C]).  
DIMENSIONS:  
INDOOR BULB LENGTH AND DIAMETER IS 4-1/2 [114] INCH BY  
1
1
/2 [13] INCH EXCEPT FOR THE AVERAGING ELEMENT WHICH IS  
/8 [3] INCH DIAMETER BY 12 FT. [3 M] LONG.  
Refer to Fig. 2.  
3
CLEARANCE NECESSARY TO REMOVE COVER.  
M9108  
ACCESSORIES:  
Compression fittings, immersion wells: Refer to the  
®
appropriate specification or the TRADELINE Cata-  
log.  
3
14439 Mounting Clips: For mounting a capillary tub-  
ing (averaging element) in a duct.  
3
60-2242—2  
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T921A,B,E-G  
INSTALLATION  
Installation  
ADD FACEPLATES FOR HORIZONTAL  
MOUNTING (T921A,B,E ONLY)  
CAUTION  
!
T921 models are shipped with a faceplate for vertical  
mounting. When mounting the T921A,B,E horizontally,  
see Table 2 to order the faceplate with the appropriate scale.  
NOTE: Do not mount the T921F,G horizontally.  
Disconnect power supply before installation to  
prevent electrical shock and equipment damage.  
WHEN INSTALLING THIS PRODUCT…  
. Installer must be a trained, experienced service tech-  
nician.  
TABLE 2—ACCESSORY FACEPLATE  
1
Scale  
Part No.  
135135A  
135135B  
135135C  
135135D  
135135Ca  
2. All wiring must comply with applicable electrical  
5
1
4
6
5
6° to 84° F [13° to 29° C]  
3° to 29° C [56° to 84° F]  
2° to 75° F [5° to 24° C]  
6° to 95° F [19° to 35° C]  
6° to 84° F [13° to 29° C]  
codes, ordinances and regulations.  
3. Do not exceed the ratings listed on the device name-  
plate.  
4. After the installation is complete, conduct a thorough  
checkout of the product operation.  
LOCATION  
aBlank faceplate.  
Locate the thermostat about 5 feet [1.5m] above the  
floor in an area with good air circulation at average room  
temperature.  
Affix the accessory faceplate when mounting the  
T921A,B,E models horizontally with contemporary cov-  
ers. Peel the backing strip from the faceplate and place it  
lightly over the vertical faceplate. Align the edges and  
corners and make sure the scales align with the markings.  
Press firmly over the entire surface. Do not attempt to  
reapply once the faceplate has been mounted.  
Do not mount 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 the sun or appliances.  
concealed pipes and chimneys.  
unheated (uncooled) areas such as an outside wall  
behind the thermostat.  
MOUNTING  
Fig. 3—Vertical mounting of T921A,B,E-G  
Thermostats on vertical conduit box.  
T921A,B,E Thermostats can also be mounted  
horizontally on horizontal conduit box using  
add-on faceplate. (Do not mount T921F,G  
horizontally.)  
1. Disconnect power supply before installation to pre-  
vent electrical shock and equipment damage.  
2. Loosen the locking screw at the bottom of the case  
with an Allen wrench.  
3. Lift off the thermostat cover.  
4
. Remove the mounting screws that secure the thermo-  
NOTE: ACCESSORY FACEPLATE FOR USE WHEN  
THE THERMOSTAT IS MOUNTED HORIZONTALLY.  
PEEL OFF BACKING AND APPLY OVER VERTICAL  
FACEPLATE AFTER MOUNTING IS COMPLETE.  
stat to the backplate and remove the backplate.  
. Fasten the backplate to the conduit box (see Fig. 3).  
5
Use the 127246A Adapter Plate Assembly (ordered sepa-  
rately) to mount the thermostat vertically on the horizontal  
conduit box; or to mount the thermostat horizontally on the  
vertical conduit box (see Fig. 4).  
CONDUIT  
BOX  
MOUNTING  
SCREWS  
NOTE: When an accessory adapter plate is used, fasten the  
adapter plate to the conduit box with the two screws  
provided. Then fasten the backplate to the adapter plate.  
8
0
70  
60  
BACKPLATE  
6. Make all electrical connections to the terminals on  
60 70 80 90  
LOCKING  
SCREW  
the back of the thermostat before mounting the instrument  
on the backplate. Refer to the Wiring section.  
H O N E Y W E L L  
COVER  
M9037  
7. Mountthethermostatonthebackplatewiththemount-  
ing screws.  
8. After performing the checkout tests, replace the ther-  
mostat cover and tighten the locking screw.  
6
0-2242—2  
4
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T921A,B,E-G  
INSTALLATION  
Fig. 4—Vertical mounting of T921A,B,E-G  
Thermostats on horizontal conduit box.  
T921A,B,E Thermostats can also be mounted  
horizontally on vertical conduit box using  
add-on faceplate. (Do not mount T921F,G  
horizontally.)  
Fig. 5—Terminals on back of thermostats.  
TOP  
TOP  
NOTE: ACCESSORY FACEPLATE FOR USE WHEN THE THERMOSTAT  
IS MOUNTED HORIZONTALLY. PEEL OFF BACKING AND APPLY  
OVER VERTICAL FACEPLATE AFTER MOUNTING IS COMPLETE.  
CONDUIT  
BOX  
BACKPLATE  
MOUNTING  
SCREWS  
(BLACK)  
80  
70  
60  
T921A, B  
T921E  
H (HEATER)  
1
27246A  
TOP  
TOP  
6
0
O
70 80 90  
ACCESSORY  
ADAPTER  
PLATE  
LOCKING  
SCREW  
H
N
E Y W E L L  
COVER  
M9036  
WIRING  
Be sure all wiring must complies with applicable electri-  
cal codes, ordinances and regulations.  
Do not exceed the following electrical ratings:  
Voltage: 24 to 30 Vac.  
Auxiliary Switch Contact Ratings: 100 VA at 30  
Vac.  
Make all electrical connections to the terminals on the  
back of the thermostat before mounting the instrument onto  
the conduit box. Terminal locations for all models are  
shown in Fig. 5. Note the difference in terminal designa-  
tions for the auxiliary switch on the T921F and G. The H  
Heater) terminal on the T921E is a black leadwire.  
Typical wiring diagrams are shown in Figs. 6 through  
0. Wire the T921 color-to-color when the modulating  
motor must drive the valve or damper open on temperature  
fall (heating application). When opposite motor action is  
required, reverse the B and W connections. Refer to the  
appropriate instructions when wiring the 2-position actua-  
tor (Figs. 9 and 10).  
AUXILIARY  
SWITCH  
TERMINALS  
T921F  
T921G  
M9038  
Fig. 6—Typical wiring diagram for T921A.  
(
SERIES 90  
MODULATING  
MOTOR  
T921A  
1
2
B
B
B
1
T
T
L1  
(
W
R
W
R
HOT)  
L2  
W
TRANSFORMER  
1
2
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND  
OVERLOAD PROTECTION AS REQUIRED.  
INTERCHANGE B AND W CONNECTIONS TO REVERSE  
DIRECTION OF MOTOR TRAVEL.  
M5989  
5
60-2242—2  
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T921A,B,E-G  
INSTALLATION • SETTING AND ADJUSTING  
Fig. 7—Typical wiring diagram for T921B.  
Fig. 9—Typical wiring diagram for T921F.  
SERIES 90  
MODULATING  
MOTOR  
T921F  
SERIES 90  
MODULATING  
MOTOR  
B
B
B
1
T
T
T921B  
2
L1  
(
2
W
R
W
R
HOT)  
B
B
B
1
L2  
T
T
W
L1  
TRANSFORMER  
W
R
W
R
(HOT)  
L2  
W
3
TRANSFORMER  
R
B
2
-POSITION  
ACTUATOR  
AUXILIARY  
SWITCH  
1
2
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND  
OVERLOAD PROTECTION AS REQUIRED.  
W
INTERCHANGE B AND W CONNECTIONS TO REVERSE  
DIRECTION OF MOTOR TRAVEL.  
M5992  
1
2
CLASS 2 POWER SUPPLY.  
INTERCHANGE B AND W CONNECTIONS TO REVERSE  
DIRECTION OF MOTOR TRAVEL.  
3
USE FOR CLASS 2 CIRCUITS. MAKES R TO B ON  
TEMPERATURE FALL BELOW THROTTLING RANGE:  
2˚ F [1˚ C] DIFFERENTIAL. SEE FIG. 10.  
M5993  
Fig. 8—Typical wiring diagram for T921E.  
Fig. 10—Typical wiring diagram for T921G.  
SERIES 90  
MODULATING  
MOTOR  
T921G  
TIMER SWITCH  
(OPTIONAL)  
T921E  
HEATER  
B
B
B
1
T
T
2
2
L1  
NIGHT  
SETBACK  
SWITCH  
W
R
W
R
H
R
(HOT)  
L2  
W
R
TRANSFORMER  
1
T
L1  
W
W
B
(HOT)  
T
L2  
W
B
B
2-POSITION  
ACTUATOR  
TRANSFORMER  
3
SERIES 90  
MODULATING  
MOTOR  
AUXILIARY  
SWITCH  
R
1
2
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND  
OVERLOAD PROTECTION AS REQUIRED.  
1
2
CLASS 2 POWER SUPPLY.  
H TERMINAL IS A BLACK LEADWIRE.  
M5988A  
INTERCHANGE B AND W CONNECTIONS TO REVERSE  
DIRECTION OF MOTOR TRAVEL.  
3
USE FOR CLASS 2 CIRCUITS. MAKES R TO B ON  
TEMPERATURE RISE ABOVE THROTTLING RANGE:  
1˚ F [0.5˚ C] DIFFERENTIAL. SEE FIG. 11.  
M5996  
Setting and Adjusting  
ADDITIONAL FEATURES:  
TEMPERATURE SETTING  
Adjust all T921 models at the top of the thermostat for  
vertically mounted models and on the left side for horizon-  
tally mounted models using the setting adjustment knob or  
an Allen wrench (see Fig. 11). The device is shipped with  
the temperature setting indicator at the center of the tem-  
perature range. Without removing the cover, turn the set-  
ting adjustment knob or use an Allen wrench so the indica-  
tor is at the desired average room temperature.  
T921B SUMMER-WINTER CHANGEOVER  
TheT921Bincludesasummer-winterchangeoverswitch.  
It is labeled COOL-HEAT. For horizontally mounted  
models, this switch is located on the left side of the  
thermostat. For vertically mounted models, it is lo-  
cated on the top of the thermostat (see Fig. 11).  
T921E NIGHT SETBACK  
The T921E includes a manual night setback switch  
located on the top of the thermostat (see Fig. 11).  
6
0-2242—2  
6
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T921A,B,E-G  
SETTING AND ADJUSTING • OPERATION  
This switch energizes a heater that offsets the ther-  
mostat approximately 10° F [6° C], lowering the  
temperature for night operation. Leave this switch in  
the OFF position for normal operation; turn it to the  
ON position for lower night time temperature.  
Fig. 11—Internal view of vertically mounted  
T921 (horizontally mounted model is similar).  
POTENTIOMETER  
WIPER  
SETTING  
1
ADJUSTMENT KNOB  
CALIBRATION  
IMPORTANT: Do not recalibrate unless the thermostat  
continues to be out-of-adjustment after several hours  
of operation.  
TEMPERATURE  
SETTING  
INDICATOR  
80  
7
0
0
INDICATOR  
LOCK SCREW  
T921 Thermostats are calibrated at the factory so when  
the room temperature matches the setpoint temperature, the  
wiper is at the center of the active potentiometer winding.  
If the thermostat is out of calibration, proceed as follows  
6
(
see Fig. 11):  
1. Remove the thermostat cover.  
. Turn the thermostat setting adjustment knob or an  
BELLOWS  
2
Allen wrench until the valve or damper motor is at mid-  
point.  
3
. Loosen the indicator lock screw and move the indica-  
tor to room temperature. Tighten the lock screw.  
. Replace the thermostat cover. Recheck the calibra-  
1
SUMMER-WINTER (COOL-HEAT) CHANGEOVER SWITCH ON  
T921B ONLY; NIGHT SETBACK SWITCH ON T921E ONLY. M9039  
4
tion and repeat the procedure if necessary.  
Operation  
In the T921, a vapor-filled bellows moves the potenti-  
ometer wiper by expanding or contracting in proportion to  
temperature changes. As the wiper moves, the appropriate  
motor winding is energized, opening or closing the valve or  
damper to compensate for the temperature change in the  
controlled area.  
Fig. 12—T921F auxiliary switch operation.  
TEMPERATURE  
+
3˚ F  
[+1.5˚ C]  
THROTTING  
RANGE (6˚ F [4˚ C])  
Operation of the auxiliary switch in the T921F,G is  
shown in Figs. 12 and 13.  
See Table 3 for the throttling range of each thermostat.  
The T921F Auxiliary Switch makes R-W at the low end of  
the throttling range on temperature rise and makes R-B at  
SETPOINT  
TEMPER-  
ATURE  
2
° F [1° C] below the low end of the throttling range on  
temperature fall.  
The T921G Auxiliary Switch makes R-W at the high  
end of the throttling range on temperature fall and R-B at  
TEMPERATURE  
FALL  
-
3˚ F  
R-W MAKES  
[
-1.5˚ C]  
1
° F [0.5° C] above the high end of the throttling range on  
2
˚ F [1˚ C]  
temperature rise.  
TEMPERATURE  
RISE  
DIFFERENTIAL  
R-B MAKES  
M5990  
TABLE 3—THERMOSTAT THROTTLING RANGES  
Model  
T921A  
T921B  
T921E  
T921F  
T921G  
Throttling Range  
2.5° F [1.5° C] midscale  
2.5° F [1.5° C] midscale  
4° F [2° C]  
6° F [4° C]  
5° F [3° C]  
7
60-2242—2  
href="
T921A,B,E-G  
OPERATION␣  
T921B  
Fig. 13—T921G auxiliary switch operation.  
1. Place the changeover switch (see Fig. 11) in the  
HEAT position and follow steps 1 through 3 of the T921A  
procedure.  
2. Move the switch to the COOL position and repeat  
steps 1 through 3 of the T921A procedure.  
3. If the valve or damper responds properly to the  
thermostat, move the setpoint to the desired temperature.  
TEMPERATURE  
TEMPERATURE  
FALL  
R-B MAKES  
+
[
2.5˚ F  
1˚ F [0.5˚ C]  
DIFFERENTIAL  
+1.5˚ C]  
R-W MAKES  
TEMPERATURE  
RISE  
T921E  
SETPOINT  
TEMPER-  
ATURE  
1. Place the night setback switch (see Fig. 11) in the  
OFF position and follow steps 1 through 3 of the T921A  
procedure.  
THROTTING  
RANGE (5˚ F [3˚ C])  
2
. Move the setpoint 5° F [3° C] above room tempera-  
ture; the valve or damper should open.  
. Move the night setback switch to the ON position; as  
-2.5˚ F  
[
-1.5˚ C]  
3
the heater in the thermostat warms up, the valve or damper  
should be driven toward the closed position. Allow 30  
minutes for the heater and bellows to warm up.  
M5991  
4
. If the valve or damper responds properly to the  
CHECKOUT  
thermostat, move the setpoint to the desired temperature.  
After the thermostat is wired and mounted, check to be  
sure the thermostat and controlled equipment are function-  
ing properly. Before proceeding, allow from one to three  
hours for the system to stabilize.  
T921F  
1. Follow steps 1 through 3 of the T921A procedure.  
2. Move the setpoint at least 10° F [6° C] above room  
temperature. The auxiliary switch should be make R-B and  
the valve or damper should be open (for heating applica-  
tion). Lower the setpoint gradually; the auxiliary switch  
should make R-W before the setting indicator reaches room  
temperature. As the setting indicator moves below room  
temperature, the valve or damper should be driven closed.  
3. If the valve or damper responds properly to the  
thermostat, move the setpoint to the desired temperature.  
T921A  
1. Set the temperature setting indicator to room tem-  
perature by using the setting adjustment knob, or an Allen  
wrench (see Fig. 11). The valve or damper motor should be  
at midpoint.  
2. Move the setpoint 5° F [3° C] below room tempera-  
ture. In a heating application, the valve or damper should  
close; in a cooling application, the valve or damper should  
open. If the valve or damper is driven in the opposite  
direction, interchange the wires at the B and W terminals.  
T921G  
1. Follow steps 1 through 3 of the T921A procedure.  
2
. Move the setpoint at least 6° F [4° C] below room  
NOTE: If a proportional action limit control is used, the  
motor may not move the damper or valve all the way  
closed or open. Check the limit action after interchang-  
ing the wiring.  
temperature. The auxiliary switch should be made R-B and  
the valve or damper should be closed (for heating applica-  
tion). Raise the setpoint gradually; the auxiliary switch  
should make R-W before the setting indicator reaches room  
temperature. As the setting indicator moves above room  
temperature, the valve or damper should open.  
3. Move the setpoint 5° F [3° C] above room tempera-  
ture. In a heating application, the valve or damper should  
open; in a cooling application, the valve or damper should  
close.  
4. If the valve or damper responds properly to the  
thermostat, move the setpoint to the desired temperature.  
4. If the valve or damper responds properly to the  
thermostat, move the setpoint to the desired temperature.  
Home and Building Control  
Home and Building Control  
Helping You Control Your World  
Honeywell Inc.  
Honeywell Limited—Honeywell Limitée  
740 Ellesmere Road  
1
985 Douglas Drive North  
Golden Valley, MN 55422  
Scarborough, Ontario  
M1P 2V9  
QUALITY IS KEY  
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