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Owner’s Guide  
TH303  
Programmable Thermostat  
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00-303-000-C  
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Table of contents  
Overview  
Configuration  
About your new thermostat .............. 1  
Quick reference to controls .............. 2  
Quick reference to screen display.... 3  
Default schedule............................. 12  
Modifying the schedule................... 13  
Setup parameters........................... 14  
Setup procedure............................. 16  
Installation  
Removing the faceplate.................... 4  
Wiring ............................................... 5  
Installing the thermostat ................... 6  
Quick start-up / Setting the clock...... 7  
Appendices  
In case of difficulty.......................... 17  
Customer assistance...................... 18  
Specifications.................................. 19  
3
-year limited warranty ................... 20  
Operating modes  
Automatic (Auto) mode..................... 8  
Manual (Man) mode ......................... 9  
Away mode..................................... 10  
Countdown mode ............................11  
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About your new thermostat  
This thermostat has been designed to control an electric heating system such as  
a baseboard heater, a radiant ceiling, a convector or a fan-forced heater.  
The thermostat CANNOT be used with:  
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a resistive load under 0.83 A  
a resistive load over 10.4 A  
a system driven by a contactor or a relay (inductive load)  
a central heating system  
SUPPLIED PARTS  
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One (1) thermostat  
Two (2) 6-32 mounting screws  
Two (2) solderless connectors  
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Quick reference to controls  
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To turn the screen backlight on,  
press the Select button once. The  
backlight will remain on for 12  
seconds.  
Help tab  
Slide up from the  
right and remove  
to view information  
on both sides.  
To  
display  
the  
setpoint  
temperature, press the Up or  
Down button once. The setpoint  
will be displayed for 5 seconds.  
Screen  
To  
modify  
the  
setpoint  
temperature, press the Up or  
Down button until the desired value  
is displayed.  
Up button  
Select button  
Down button  
To enter or exit the programming  
mode, press the Select button and  
hold for 3 seconds.  
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Quick reference to screen display  
Countdown mode (see page 11)  
Flashes during  
Countdown mode  
Setpoint temperature  
Time  
Day  
(
see page 2)  
Automatic mode (see page 8)  
Manual mode (see page 9)  
Away mode (see page 10)  
Heating intensity indicator  
Ambient temperature  
(No icon appears when  
heating is off.)  
Periods (see page 12)  
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Removing the faceplate  
TURN OFF POWER OF THE HEATING  
SYSTEM AT THE MAIN ELECTRICAL  
PANEL TO AVOID ELECTRIC SHOCK.  
WARNING: Installation must be carried  
out by a certified electrician and must  
comply with national and local electrical  
codes.  
Loosen the screw holding the faceplate to  
the base. The screw cannot be  
completely removed and remains captive  
on the base. Remove the faceplate from  
the base by pulling the bottom section.  
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Wiring  
Connect either one of the  
thermostat wires to the  
heater wire and the other  
one to the power supply  
2-wire installation  
4-wire installation  
Power supply  
wire  
using  
solderless  
connectors for copper wires.  
NOTE: Special CO/ALR  
solderless connectors must  
be used when connecting  
with aluminium conductors.  
Power supply  
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Installing the thermostat  
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Install the base onto an electrical  
box.  
Place the FAN switch on Yes only if  
the thermostat is connected to  
a
fan-forced heater. Otherwise leave  
at No.  
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If applicable, peel off the protective  
sticker from the thermostat’s screen.  
FAN switch  
Keep air vents at top and  
Reinstall the faceplate on the base  
and secure it in place with the screw.  
bottom of thermostat clean  
and unobstructed at all times.  
Apply power to the thermostat at the  
main electrical panel.  
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Quick Start-up / Setting the clock and date  
When you power the thermostat, the Time menu flashes on the screen. Set the  
thermostat’s clock and date as follows:  
Time Menu  
Select the format  
Set the hour  
Set the minutes  
Set the year  
Set the month  
Set the date  
Normal display  
NOTE: At any time, you can access the Time menu by pressing the Select button  
for 3 seconds and then pressing the Up button once.  
Your new thermostat is already preprogrammed  
and is now controlling the temperature!  
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Automatic (Auto) mode  
In Automatic mode, the thermostat follows the programmed schedule (see page 12).  
To place the thermostat in Automatic (Auto) mode:  
Normal display  
Auto mode  
Select Auto  
Temporary override  
While the thermostat is in Automatic mode, you can press the Up or Down button to modify  
the temperature. The new temperature will be used until the end of the current period. Auto  
will flash during the override. You can cancel the override by pressing the Select button twice  
to return to Automatic mode.  
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Manual (Man) mode  
Use the Manual mode if you wish to keep the thermostat at the same  
temperature indefinitely. In this mode, the thermostat will remain at this  
temperature until you press the Up or Down button to change it.  
To place the thermostat in Manual (Man) mode:  
Normal display  
Manual mode  
Select Manual  
Set temperature  
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Away mode  
The Away mode can be used when you are away for an undetermined length of  
time. For frost protection while saving energy, the Away temperature is set by  
default at 15°C (59°F) and cannot be modified by simply pressing the Up or Down  
button. To modify the Away temperature, see page 16.  
NOTE: The Away mode can also be used to prevent tampering of the setpoint  
temperature in the summer season when heating is not required.  
To place the thermostat in Away mode:  
Normal display  
Away mode  
Select Away  
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Countdown mode  
Use the Countdown mode if you wish to keep the same temperature for a predetermined  
length of time. The choices of countdown times are: 15, 30, 45 min, 1, 2, 4, 8, 12, 18 hr and 1  
to 14 days. At the end of the countdown, the thermostat automatically returns to the previous  
mode and uses the temperature programmed for that mode. At any time, you can cancel the  
Countdown mode by pressing the Select button.  
To place the thermostat in Countdown mode:  
Optional (last settings are used by default)  
Countdown  
mode  
NOTE:  
Normal display  
At any time during the  
Countdown mode, you  
can adjust the count-  
down time and tempera-  
ture by performing the  
steps shown inside the  
dotted rectangle.  
Select Countdown  
Set time  
Set temperature  
To cancel the Countdown mode  
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Default schedule  
When placed in Automatic mode (see page 8), the thermostat follows the programmed  
schedule. By default, the thermostat is programmed with the following schedule:  
Monday to Friday  
Saturday and Sunday  
(
Mo, Tu, We, Th & Fr)  
(Sa & Su)  
Period  
Wake  
Starting time  
6:00 (6:00 AM)  
8:00 (8:00 AM)  
18:00 (6:00 PM)  
22:00 (10:00 PM)  
Temperature  
21.0°C (70°F)  
16.5°C (62°F)  
21.0°C (70°F)  
16.5°C (62°F)  
Starting time  
Temperature  
6:00 (6:00 AM)  
21.0°C (70°F)  
Leave  
Return  
Sleep  
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22:00 (10:00 PM)  
16.5°C (62°F)  
The schedule consists of 4 periods per day, which represents a typical work day. However, you  
can program the thermostat to skip (cancel) the periods that do not apply to your situation. For  
example, Leave and Return periods are skipped for the weekend in the default schedule.  
You can choose a different program every day; i.e., each period can have a different starting  
time and a different temperature every day.  
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Modifying the schedule  
To modify the schedule, proceed as follows:  
Select Exit to return  
to normal display  
Select Exit to return to  
the day selection menu  
(
3 sec.)  
Normal display  
Program menu  
Select the days*  
Select the period  
Set the hour  
Set the minutes  
Set the temperature  
*
The days can be selected collectively (Monday to Friday, Saturday & Sunday, or Monday to Sunday) or individually.  
To skip a period: When the hour or the temperature of the period is flashing, press the Up and Down  
buttons at the same time. (Alternatively, set its hour between 23:00 [11:00 PM] and 0:00 [12:00 AM] or  
its temperature below 5°C [41°F].) Its time and temperature display will be replaced by dashes (-).  
NOTE: If you do not press any button for one minute, the thermostat will automatically save any  
changes you have made and will return to its normal display  
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Configuration parameters  
Display  
Parameter  
Options  
Default setting  
To modify  
Fan1  
Yes / No  
No  
FAN switch (see page 6)  
Time format  
12h / 24h  
°C / °F  
24h  
Time menu (see page 7)  
Temperature unit  
Away temperature2  
Daylight Saving Time3  
Early Start4  
°C  
10°C (50°F)  
On  
5°C - 30°C (41°F - 86°F)  
On / Off  
Configuration menu  
(
see page 16)  
On / Off  
Off  
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Configuration parameters (cont’d)  
Fan  
1
Place at Yes if you have a fan-forced heater (to prevent premature burnout of the motor). Leave at No for  
better temperature regulation if you do not have a fan-forced heater.  
2
Away temperature  
Set the temperature you wish to use when the thermostat is in Away mode (see page 10).  
3
Daylight Saving Time  
When the Daylight Saving Time function is enabled (On), the thermostat automatically switches to Daylight  
Saving Time on the second Sunday of March and to normal time on the first Sunday of November.  
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Early Start  
Early Start is used in Automatic mode only. When Early Start is enabled (On), the thermostat determines  
when to start heating so the desired temperature is attained at the beginning of Wake and Return periods.  
When Early Start is disabled (Off), heating starts only at the beginning of Wake and Return periods; thus  
there is a delay before you reach the desired temperature.  
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Configuration procedure  
The Configuration menu is shown below.  
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Press the Select button for 3 seconds to enter the main menu.  
Press the Up button twice to enter the Configuration (Conf) menu.  
Configuration  
Menu  
NOTE: If you do not press  
any button for one minute, the  
thermostat will automatically  
save any changes you have  
made and will return to its  
Set unit of  
Set Away  
Set Daylight  
Saving Time  
Set  
temperature  
temperature  
Early Start  
To confirm  
To confirm  
To confirm  
To confirm  
normal display  
.
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In case of difficulty  
PROBLEM  
SOLUTIONS  
This is normal. Ensure that the heater capacity does not exceed the thermostat’s  
maximum load.  
Thermostat is hot.  
Remediate if any the following conditions exists:  
Displayed temperature  
is wrong.  
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The thermostat is exposed to air draft.  
The thermostat is located near or above a heat source such as a light dimmer.  
Display disappears and The thermal protection device on the heater has temporarily opened. This can  
reappears after a few  
minutes.  
happen if the heater is obstructed by furniture or curtain and has overheated, or if  
the heater’s thermal protection device is too sensitive.  
The thermostat was without power for more than 4 hours. Set its clock and date  
TIME is flashing.  
(Time menu).  
Temperature does not  
change according to the  
programmed schedule.  
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Ensure the thermostat is in Automatic mode.  
Check the clock (Time menu) and the schedule (Prog menu). If the thermostat  
is configured for 12-hour format, ensure that AM or PM appears on the screen.  
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Customer assistance  
If you have any questions about the product, contact us at:  
7
05 Montrichard  
Saint-Jean-sur-Richelieu, Quebec  
J2X 5K8  
Canada  
To reset the thermostat,  
press both Down and  
Select buttons and hold.  
After 3 seconds, RST appears. After  
the next 5 seconds, when RST  
disappears, release the buttons.  
Except for the time and date, the  
thermostat has now returned to its  
default settings.  
Tel: 1-800-831-AUBE (2823)  
Email: aube.service@honeywell.com  
For more information on our products, go to  
www.aubetech.com  
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Specifications  
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Supply: 120/240 VAC, 60 Hz  
Minimum load:  
0.83 A (resistive only)  
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00 W @ 240 VAC  
00 W @ 120 VAC  
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Maximum load:  
10.4 A (resistive only)  
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500 W @ 240 VAC  
250 W @ 120 VAC  
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Setpoint range: 5°C to 30°C (41°F to 85°F)  
Display range: 0°C to 70°C (32°F to 99°F)  
Setpoint/display resolution: ±0.5°C (±1°F)  
Operation: 0°C to 50°C (32°F to 120°F)  
Storage: -20°C to 50°C (-4°F to 120°F)  
Permanent memory:You do not need to adjust the temperature settings or the thermostat’s  
configurations following a power outage. However, you might need to  
set the thermostat’s clock and date if the outage lasts more than 4  
hours.  
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3
-year limited warranty  
Honeywell warrants this product, excluding battery, to be free from defects in the workmanship or materials, under normal use and  
service, for a period of three (3) years from the date of purchase by the consumer. If at any time during the warranty period the  
product is determined to be defective or malfunctions, Honeywell shall repair or replace it (at Honeywell's option).  
If the product is defective,  
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i) return it, with a bill of sale or other dated proof of purchase, to the place from which you purchased it, or  
ii) contact Honeywell. Honeywell will make the determination whether the product should be returned, or whether a replace-  
ment product can be sent to you.  
This warranty does not cover removal or reinstallation costs. This warranty shall not apply if it is shown by Honeywell that the defect  
or malfunction was caused by damage which occurred while the product was in the possession of a consumer.  
Honeywell's sole responsibility shall be to repair or replace the product within the terms stated above. HONEYWELL SHALL NOT  
BE LIABLE FOR ANY LOSS OR DAMAGE OF ANY KIND, INCLUDING ANY INCIDENTAL OR CONSEQUENTIAL DAMAGES  
RESULTING, DIRECTLY OR INDIRECTLY, FROM ANY BREACH OF ANY WARRANTY, EXPRESS OR IMPLIED, OR ANY  
OTHER FAILURE OF THIS PRODUCT. Some provinces, states or regions do not allow the exclusion or limitation of incidental or  
consequential damages, so this limitation may not apply to you.  
THIS WARRANTY IS THE ONLY EXPRESS WARRANTY HONEYWELL MAKES ON THIS PRODUCT. THE DURATION OF ANY  
IMPLIED WARRANTIES, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PUR-  
POSE, IS HEREBY LIMITED TO THE THREE-YEAR DURATION OF THIS WARRANTY. Some provinces, states or regions do not  
allow limitations on how long an implied warranty lasts, so the above limitation may not apply to you.  
This warranty gives you specific legal rights, and you may have other rights which vary from one province, state or region to  
another.  
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