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T822A,D,F,G; TS822A; and T8022D  
Low Voltage Thermostats  
Application  
T822A,D,F, TS822A, and T8022D Thermostats pro-  
vide control of heating systems. T822G provides control of  
AC heating or cooling appliances.  
CAUTION  
Disconnect power supply before beginning instal-  
lation to prevent electrical shock or equipment  
damage.  
The T822A two-wire switch thermostat provides low  
voltage control of heating systems and features a fixed heat  
anticipator.  
The T822D and T8022D two-wire, mercury switch  
thermostat provides low voltage control of heating systems  
and features an adjustable heat anticipator.  
The T822F three-wire, mercury switch thermostat pro-  
vides low voltage control of heating systems and features  
an adjustable heat anticipator and AUTO-ON fan switch-  
ing.  
The T822G three-wire, mercury switch thermostat pro-  
vides low voltage control of AC heating and cooling appli-  
ances and features an adjustable heating anticipator and  
nonadjustable cooling anticipator.  
LOCATION  
Locate the thermostat about 5 ft [1.5 m] above the floor  
on an inside wall in an area with good air circulation at  
average temperature.  
Do not mount the thermostat where it can be affected by:  
drafts or dead spots behind doors or in corners.  
hot or cold air from ducts.  
concealed pipes and chimneys.  
radiant heat from the sun, fireplaces, or appliances.  
unheated (uncooled) areas behind the thermostat,  
such as an outside wall.  
MOUNTING AND WIRING  
The TS822A two-wire, mercury switch thermostat pro-  
vides millivoltage control of heating systems.  
T822A,D; TS822A, and T8022D Thermostats are avail-  
able with a positive OFF switch. All models are available  
with temperature range stops.  
Disconnect power supply before beginning installation  
to prevent electrical shock or equipment damage.  
All wiring must comply with local codes and ordi-  
nances.  
T822A,D,F,G and TS822A Thermostats are designed to  
be mounted vertically on a wall or a vertical outlet box.  
T8022D is designed to be mounted horizontally on a wall.  
In a 250 or 500 mV application, use No. 14 wire if  
possible and make the run as short as possible; remember  
this when selecting a location. For maximum wire lengths  
of a 750 mV application, see Table 1.  
M
Recycling Notice  
If this control is replacing a control that contains mer-  
cury in a sealed tube, do not place your old control in  
thetrash.  
Contact your local waste management authority for  
instructions regarding recycling and the proper disposal of  
this control, or of an old control containing mercury in a  
sealed tube.  
TABLE 1—WIRE LENGTH.  
Max. Combined  
Wire  
Size  
Max. Length  
2-Wire Cable  
Length  
If you have questions, call Honeywell Inc. at  
-800-468-1502.  
2-Single Wires  
1
ft  
30  
50  
80  
m
9.0  
15.0  
24.5  
ft  
60  
100  
160  
m
No. 18  
No. 16  
No. 14  
18.0  
30.0  
40.0  
Installation  
WHEN INSTALLING THIS PRODUCT…  
. Read these instructions carefully. Failure to follow  
1
them could damage the product or cause a hazardous condi-  
tion.  
1
. In replacement applications, check the existing ther-  
mostat wires for cracked or frayed insulation. Replace any  
wires in poor condition. If the wire is plastered into the  
wall, make a hole next to the wires and loosen the wires so  
they can be pushed back into the wall later.  
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 tech-  
2
. In new installations, run wiring (if necessary) to the  
thermostat location.  
. Connect the wires to the terminals on the back of the  
nician.  
4. After installation is complete, check out product  
3
operation as provided in these Instructions.  
thermostat. See Figs. 1 through 6 for internal schematics  
and typical hookup diagrams.  
CAUTION  
J. H. • Rev. 2-01 •
• ©Honeywell Inc. 2001 • Form Number 69-05104  
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4
. Remove thermostat cover by pulling outward on  
bottom edge of cover until it snaps free of the thermostat  
base. Carefully remove and discard the foam plastic ship-  
ping insert. This insert protects the switch and bimetal  
assembly during shipping.  
Fig. 3—T822A,D and T8022D in typical oil  
heating application.  
T822A,D; T8022D  
TEMP. FALL  
5
. Set the adjustable heat anticipator indicator  
T822D,F,G only) to match the current draw of the primary  
heating control (see Heat Anticipator Setting).  
. Push excess wire back through the hole and plug any  
1
(
L1  
(HOT)  
R
T
T
L2  
6
H1  
2
opening with insulation to prevent drafts that may affect  
thermostat performance.  
OIL  
PRIMARY  
W
7. Loosely fasten the thermostat to the wall or outlet  
H1  
ANTICIPATOR  
box with a screw through the top mounting hole. Do not  
tighten.  
8
. Level the thermostat exactly using a spirit level or  
1
2
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD  
PROTECTION AS REQUIRED.  
plumb line. Tighten the mounting screws.  
T822D, T8022D ADJUSTABLE HEAT ANTICIPATOR SHOWN. T822A  
IMPORTANT: An incorrectly leveled thermostat will  
HAS A FIXED HEAT ANTICIPATOR.  
M1184A  
causethetemperaturecontroltodeviatefromsetpoint.  
9. Replace the thermostat cover.  
Fig. 4—T822F in typical heating application.  
Fig. 1—T822A,D and T8022D in typical electric  
heating application.  
1
L1  
(
HOT) L2  
T822A,D; T8022D  
T822F  
TEMP. FALL  
LIMIT  
CONTROL  
2
1
TEMP. FALL  
FAN  
SWITCH  
L1  
(HOT)  
R
R
G
L2  
ON  
H1  
H1  
AUTO  
FAN RELAY  
3
W
H1  
H1  
ANTICIPATOR  
ELECTRIC  
HEAT RELAY  
ANTICIPATOR  
W
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD  
PROTECTION AS REQUIRED.  
HEAT RELAY  
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD  
2
3
ALTERNATE LIMIT CONTROL LOCATION.  
PROTECTION AS REQUIRED.  
M5538  
T822D, T8022D ADJUSTABLE HEAT ANTICIPATOR SHOWN. T822A  
HAS A FIXED HEAT ANTICIPATOR.  
M1164B  
Fig. 5—T822G in typical heating or cooling  
application.  
Fig. 2—T822A,D and T8022D in typical gas  
heating application.  
L1  
1
HOT) L2  
(
T822A,D; T8022D  
TEMP. FALL  
T822G  
1
TEMP. FALL  
L1  
R
(HOT)  
R
L2  
C1  
H1  
ANTICIPATOR  
H1  
C1  
Y
2
W
COOL RELAY  
HEAT RELAY  
2
H1  
GAS  
CONTROL  
ANTICIPATOR  
H1  
ANTICIPATOR  
W
1
2
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD  
PROTECTION AS REQUIRED.  
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD  
PROTECTION AS REQUIRED.  
T822D, T8022D ADJUSTABLE HEAT ANTICIPATOR. T822A HAS A  
FIXED HEAT ANTICIPATOR.  
M1183A  
2
USE EITHER "W" OR "Y" TERMINAL, BUT NOT BOTH.  
M5512  
2
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9
. Turn the system switch to OFF, and turn off power.  
0. Adjust the heat anticipator to match the reading on  
the ammeter.  
1. Disconnect the ammeter, reconnect the W wire, and  
mount the thermostat. Continue with system checkout.  
NOTE: For best performance, the heat anticipator may  
require further adjustment. To lengthen burner-on time,  
move the indicator in the direction of the longer ar-  
rows—not more than one-half scale marking at a time.  
To shorten burner-on time, move indicator in opposite  
direction.  
Fig. 6—TS822A in typical millivoltage heating  
application.  
1
1
TS822A  
TEMP. FALL  
PILOTSTAT  
MILLIVOLTAGE CONTROL  
GAS CONTROL (IF USED)  
R
TH  
TH/  
PP  
H1  
PP  
MILLIVOLTAGE  
GENERATOR  
1
Y
LIMIT  
CONTROL  
Checkout  
W
CAUTION  
1
CONNECT R AND W TERMINALS FOR 750 mV SYSTEMS. CONNECT  
R AND Y TERMINALS FOR 250/500 mV SYTSEMS.  
M1294  
CAUTION  
Do not check thermostat operation by shorting  
across system control terminals. This damages the  
thermostat heat anticipator.  
Setting and Adjustment  
TEMPERATURE SETTING  
IMPORTANT: The T822A,D,F, TS822A, and T8022D  
can only be installed in heating applications. Per-  
form only steps 1 and 2. The T822G can be installed  
for either heating or cooling applications. If installed  
for heating, perform steps 1 and 2. If installed for  
cooling, perform step 6.  
Move the temperature setting lever to the desired control  
point on the temperature scale. On positive off models, the  
control circuit is broken when the lever is moved to the  
extreme low end of the temperature scale. On models with  
temperature range stops, move the temperature setting le-  
ver only between the two temperature range stops.  
1
. Set T822F FAN switch to AUTO. Fan operation is  
HEAT ANTICIPATOR SETTING (T822D,F,G  
ONLY)  
controlled by the thermostat.  
2. Move temperature setting lever about 10° F [6° C]  
above room temperature.  
NOTE: Before Changing your heat anticipator setting,  
consultyourinstallingcontractororequipmentmanu-  
facturer. Heat anticipators on some models are fac-  
tory set to the manufacturer's specifications.  
Gas or oil heating systems: heating starts immedi-  
ately. Fan starts after short delay.  
Electric heating systems: heating and fan start imme-  
diately.  
3
. Move temperature setting lever about 10° F [6° C]  
IMPORTANT: The T822D,F,G has an adjustable heat  
anticipator and operates properly ONLY IF THE  
ANTICIPATOR IS ADJUSTED TO MATCH THE  
CURRENT DRAW OF THE PRIMARY CONTROL.  
Use the T822D,F,G only on systems with current  
draws that fall within the range of the heat anticipa-  
tor. Do not use this device on Powerpile (millivolt)  
Systems.  
below room temperature.  
Gas or oil heating systems: heating stops immedi-  
ately. Fan stops after a short delay.  
Electric heating systems: heating and fan stop imme-  
diately.  
4. Set T822F FAN switch to ON. Fan runs continu-  
ously.  
5. Set temperature lever and T822F FAN switch to the  
desired settings.  
A current rating is usually stamped in the nameplate of  
the primary control. Set the adjustable heat anticipator  
indicator to match the value given on the nameplate.  
If current rating is not available, proceed as follows to  
determine the rating:  
CAUTION  
Do not operate T822G in cooling applications if  
the outdoor temperature is below 50° F [10° C].  
Refer to the air conditioner manufacturer’s  
recommendations.  
1
. Turn off power.  
2. Wirethermostat, exceptforconnectiontoWterminal,  
but do not mount it on the wall.  
. ConnecttheammeterbetweenWwireandWterminal  
on the thermostat in series with the primary control.  
3
6
. T822G COOLING APPLICATIONS ONLY:  
4
5
6
7
. Prepare the system for operation.  
. Turn on power.  
. Turn system switch to heat.  
. Increasethermostatsetpointasnecessarytogetsystem  
NOTE: To prevent compressor short cycling, install a five  
minute time delay. The time delay will not activate the  
compressor for five minutes after the thermostat turns  
off the compressor or for five minutes after the system  
receives power.  
operating.  
8. With the system operating through the ammeter, wait  
one minute, then read the ammeter.  
3
69-0510—4  
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Move the temperature setting lever about 10° F [6° C]  
below room temperature. Cooling and fan should start  
immediately. Move temperature setting lever about 10° F  
3. Move the setting lever to a low setting. Wait at least  
five minutes for temperature to stabilize.  
4. Slowly move the setting lever until it reads the same  
as the thermometer.  
[
6° C] above room temperature. Cooling and fan should  
stop immediately.  
5. Remove cover. Holding the setting lever so it does  
not move, reinsert wrench and carefully turn counter-  
until the mercury just rolls to the left end  
of the tube, but no farther.  
RECALIBRATION  
clockwise  
Thesethermostatsarecalibratedatthefactoryandshould  
not need recalibration. If the thermostat seems out of ad-  
justment, first check for accurate leveling. To check cali-  
bration, proceed as follows:  
6. Recheck calibration. Set thermostat system switch  
for desired operation and replace the cover.  
1
. Move the temperature setting lever to the low end of  
the temperature scale.  
. Remove the thermostat cover. Move the setting lever  
Fig. 7—Recalibration procedure.  
2
until the switch just makes contact. The mercury in the  
switch will drop to the contact end of the tube.  
COIL SHOWN WITHOUT  
HEAT ANTICIPATOR  
3. Replace the cover and wait five minutes for the cover  
and the thermostat to lose the heat it has gained from your  
hands. If the thermometer pointer and the setting lever  
indicator read approximately the same, no recalibration is  
needed.  
If recalibration appears necessary, proceed as follows:  
1
. Place the temperature setting lever at the same setting  
as the thermometer. Remove cover.  
. Insert104994ACalibrationWrench(orderseparately)  
CALIBRATION  
WRENCH  
M2044  
2
onto the hex nut under the coil. See Fig. 7. Holding the  
setting lever so it does not move, turn the wrench clock-  
wise  
until the switch just breaks contact.  
Remove wrench and replace cover.  
Automation and Control Solutions  
Honeywell Internationals Inc.  
Honeywell Limited—Honeywell Limitée  
1
985 Douglas Drive North  
35 Dynamic Drive  
Golden Valley, Minnesota 55422  
Scarborough, Ontario M1V 4Z9  
www.honeywell.com/yourhome