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TRADELINE  
T822D, TS822A  
Heating Thermostats  
radiant heat from the sun, fireplaces, or appliances.  
concealed pipes and chimneys.  
unheated (uncooled) areas behind the thermostat,  
such as an outside wall.  
Application  
The T882D two-wire, mercury switch thermostat pro-  
vides low voltage control of heating systems and features  
an adjustable heat anticipator. Some models include a  
positive OFF switch and temperature range stops.  
The TS822A two-wire, mercury switch thermostat pro-  
vides millivoltage control of heating systems and features  
a positive OFF switch.  
MOUNTING AND WIRING  
Disconnect power supply before beginning installation  
to prevent electrical shock or equipment damage.  
All wiring must comply with local codes and ordinances.  
T822D and TS822A Thermostats are designed to be  
mounted on a wall or on a vertical outlet box. In a 250 or  
5
00 mV application, use No. 14 wire if possible and make  
Recycling Notice  
the run as short as possible; remember this when select-  
ing a location. For maximum wire lengths in a 750 mV  
application, see Table 1.  
This control contains mercury in a sealed tube. Do not  
place control in the trash at the end of its useful life.  
If this control is replacing a control that contains mercury  
in a sealed tube, do not place your old control in the trash.  
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  
Length  
2-Single Wires  
Wire  
Size  
Max. Length  
2-Wire Cable  
ft  
[m]  
ft  
[m]  
No. 18  
No. 16  
No. 14  
30  
50  
80  
[9.0]  
60  
[18.0]  
[30.0]  
[40.0]  
[15.0]  
[24.5]  
100  
160  
Installation  
WHEN INSTALLING THIS PRODUCT…  
. Read these instructions carefully. Failure to fol-  
low them could damage the product or cause a hazardous  
condition.  
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.  
1
2
. Check the ratings given in the Instructions and on  
the product to make sure the product is suitable for your  
2
. In new installations, run wiring (if necessary) to the  
thermostat location.  
. Connect the wires to the terminals on the back of the  
application.  
3
technician.  
4
3
. Installer must be a trained, experienced service  
thermostat. See Figs. 1 through 4 for internal schematic and  
typical hookup diagrams.  
. After installation is complete, check out product  
operation as provided in these Instructions.  
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.  
CAUTION  
Disconnect power supply before beginning in-  
stallation to prevent electrical shock or equip-  
ment damage.  
5. Set the adjustable heat anticipator indicator (T822D  
only) to match the current draw of the primary heating  
control (see Heat Anticipator Setting).  
6
. Push excess wire back through the hole and plug any  
LOCATION  
opening with insulation to prevent drafts that may affect  
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.  
thermostat performance.  
7. Loosely fasten the thermostat to the wall or  
outlet box with a screw through the top mounting hole.  
Adjust the thermostat so it is approximately level and  
start the second screw through the bottom mounting  
hole. Do not tighten.  
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.  
J. H. • Rev. 2-93 • 
• ©Honeywell Inc. 1993 • Form Number 69-05092  
M
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8
. Level the thermostat exactly using a spirit level or  
plumb line. Tighten the mounting screws.  
Fig. 2—T822D in typical gas heating application.  
IMPORTANT: An incorrectly leveled thermostat will  
T822A,D; T8022D  
causethetemperaturecontroltodeviatefromsetpoint.  
TEMP. FALL  
1
L1  
R
(HOT)  
L2  
9
. Replace the thermostat cover  
H1  
2
W
Settings and Adjustments  
H1  
GAS  
ANTICIPATOR  
CONTROL  
TEMPERATURE SETTING  
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, temperature setting lever can be  
moved only between the two temperature range stops.  
1
2
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD  
PROTECTION AS REQUIRED.  
T822D, T8022D ADJUSTABLE HEAT ANTICIPATOR. T822A HAS A  
FIXED HEAT ANTICIPATOR.  
M1183A  
Fig. 3—T822D in typical oil heating application.  
HEAT ANTICIPATOR SETTING (T822D Only)  
T822A,D; T8022D  
TEMP. FALL  
IMPORTANT: This thermostat has an adjustable heat  
anticipator and will operate properly ONLY IF THE  
ANTICIPATOR IS ADJUSTED TO MATCH THE  
CURRENT DRAW OF THE PRIMARY CONTROL.  
Use this thermostat only on systems with current  
draws that fall within the range of the heat anticipator.  
Do not use device on Powerpile (millivolt) Systems.  
1
L1  
R
T
T
(HOT)  
L2  
H1  
2
OIL  
PRIMARY  
W
H1  
ANTICIPATOR  
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:  
1
2
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD  
PROTECTION AS REQUIRED.  
T822D, T8022D ADJUSTABLE HEAT ANTICIPATOR SHOWN. T822A  
HAS A FIXED HEAT ANTICIPATOR.  
M1184A  
1
. Turn off power.  
2. Wire thermostat, except for connection to W termi-  
Fig. 4—TS822A in typical millivoltage heating  
application.  
nal, but do not mount it on the wall.  
. Connect ammeter between W wire and W terminal  
on the thermostat.  
3
TS822A  
PILOTSTAT  
MILLIVOLTAGE CONTROL  
4
5
6
7
. Prepare the system for operation.  
. Turn on power.  
. Turn system switch to heat.  
. Increase thermostat setpoint as necessary to get sys-  
TEMP. FALL  
GAS CONTROL (IF USED)  
2
R
TH  
TH/  
PP  
H1  
PP  
tem operating.  
1
MILLIVOLTAGE  
GENERATOR  
Y
LIMIT  
Fig. 1—T822D in typical electric heating  
application.  
W
CONTROL  
1
2
CONNECT R AND W TERMINALS FOR 750 mV SYSTEMS. CONNECT  
R AND Y TERMINALS FOR 250/500 mV SYSTEMS.  
T822A,D; T8022D  
TEMP. FALL  
LIMIT  
POSITIVE OFF SWITCH PROVIDES COMPLETE CONTROL CIRCUIT  
SHUTOFF. DOES NOT REPLACE POWER SUPPLY DISCONNECT  
SWITCH.  
CONTROL  
2
1
L1  
M1311  
R
(HOT)  
L2  
H1  
8
. With the system operating through the ammeter, wait  
3
W
one minute, then read the ammeter.  
H1  
ELECTRIC  
9. Turn the system switch to OFF, and turn off power.  
ANTICIPATOR  
HEAT RELAY  
10. Adjust the heat anticipator to match the reading on  
the ammeter.  
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD  
PROTECTION AS REQUIRED.  
11. Disconnect the ammeter, reconnect the W wire,  
and mount the thermostat. Continue with system check-  
out.  
2
3
ALTERNATE LIMIT CONTROL LOCATION.  
T822D, T8022D ADJUSTABLE HEAT ANTICIPATOR SHOWN. T822A  
HAS A FIXED HEAT ANTICIPATOR.  
M1164B  
2
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NOTE: The heat anticipator may require further adjust-  
ment for best performance. To lengthen burner-on  
time, move the indicator in the direction of the longer  
arrows—not more than one-half scale marking at a  
time. To shorten burner-on time, move indicator in  
opposite direction.  
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  
leverindicatorreadapproximatelythesame, norecalibration  
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)  
2
Checkout  
onto the hex nut under the foil. See Fig. 5. Holding the  
setting lever so it does not move, turn the wrench clock-  
wise  
wrench and replace cover.  
. Move the setting lever to a low setting. Wait at least  
five minutes for temperature to stabilize.  
. Slowly move the setting lever until it reads the same  
as the thermometer.  
. Remove cover. Holding the setting lever so it does  
not move, reinsert wrench and carefully turn counterclock-  
wise until the mercury just rolls to the left end of the  
until the switch just breaks contact. Remove  
CAUTION  
3
Do not check thermostat operation by shorting  
across system control terminals. This damages the  
thermostat heat anticipator.  
4
5
1
. Move temperature setting lever about 10° F [6° C]  
above room temperature:  
Gas or oil heating systems: Heating starts immedi-  
ately. Fan starts after short delay.  
Electric heating systems: Heating and fan start  
immediately.  
tube, but no farther.  
6. Recheck calibration. Set thermostat system switch  
for desired operation and replace cover.  
2. Move temperature setting lever about 10° F [6° C]  
below room temperature:  
Fig. 5—Recalibration procedure.  
Gas or oil heating systems: Heating stops immedi-  
ately. Fan stops after a short delay.  
Electric heating systems: Heating and fan stop  
immediately.  
COIL SHOWN WITHOUT  
HEAT ANTICIPATOR  
RECALIBRATION  
Thesethermostatsarecalibratedatthefactoryandshould  
not need recalibration. If the thermostat seems out of ad-  
justment, first check for accurate leveling. To check cali-  
bration, proceed as follows:  
1
. Move the temperature setting lever to the low end of  
the temperature scale.  
. Remove the thermostat cover. Move the setting lever  
CALIBRATION  
WRENCH  
M2044  
2
until the switch just makes contact. The mercury in the  
switch will drop to the contact end of the tube.  
3
69-0509—2  
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Automation and Control Solutions  
Honeywell International Inc. Honeywell Limited—Honeywell Limitée  
1
985 Douglas Drive North  
35 Dynamic Drive  
Golden Valley, MN 55422  
Scarborough, Ontario M1V 4Z9  
www.honeywell.com/yourhome