Stelpro STE241 User manual

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For further information or to consult this guide online, please visit
our website at www.stelpro.com
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USER’S GUIDE
STE241
LOW VOLTAGE
ELECTRONIC THERMOSTAT (24V)

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Before installing and operating this product, the owner and/or installer
must read, understand and follow these instructions and keep them
handy for future reference. If these instructions are not followed, the
warranty will be considered null and void and the manufacturer deems
no further responsibility for this product. Moreover, the following
instructions must be adhered to in order to avoid personal injuries or
property damages, serious injuries and potentially fatal electric shocks.
         
according to the electric and building codes effective in your region.
Do NOT connect this product to a supply source other than 24 VAC and

the appropriate circuit breaker or fuse. You must regularly clean dirt

air vent. Do not install thermostat in a wet place. However, installing it in
isolated walls is allowed.
Note:
When a part of the product specication must be changed to improve operability
or other functions, priority is given to the product specication itself. In such
instances, the instruction manual may not entirely match all the functions of the
actual product.
Therefore, the actual product and packaging, as well as the name and illustration,
may differ from the manual.
The screen/LCD display shown as an example in this manual may be different
from the actual screen/LCD display.
WARNING

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The STE241 low voltage electronic thermostat (24 V) is designed to control relays
(electronic or not). The allowed resistive maximum load is 12 W at 24 V (0.5 A).
Then, relays (electronic or not) connected to the thermostat can control electric
baseboards with or without fans, convectors, fan heaters and electric furnaces.
This thermostat can be connected to Stelpro relays (with or without transformers).
Moreover, the triac contact is really quiet.
This thermostat is not compatible with the following
installations:
• resistive load of more than 12 W at 24 VAC (0.5 A)
Parts supplied:
• one (1) thermostat
• two (2) mounting screws
Selection of thermostat location
The thermostat must be mounted on a wall facing the heating unit, at around
1.5 m (5 feet) above the oor level, on a section of the wall exempt from pipes
or air ducts.
Do not install the thermostat in a location where temperature measurements could
be altered. For example:
• close to a window, on an external wall, or close to a door leading outside
• exposed directly to the light or heat of the Sun, a lamp, a replace or any other
heat source
• close or in front of an air outlet
• close to concealed ducts or a chimney
• in a location with poor air ow (e.g. behind a door), or with frequent air drafts
conditions (e.g. head of stairs).
DESCRIPTION
INSTALLATION

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Thermostat mounting and connection
1. Ensure that the air vents of the thermostat are clean and clear of any
obstruction.
2. Using a screwdriver, loosen the screw retaining the mounting base and front
part of the thermostat. Remove the front part of the thermostat from the
mounting base by tilting it upward.
N.B. The following photos show a connection box installation as a reference only.
A connection box is not necessary or required.
3. Align and secure the mounting base using the two screws supplied.

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4. Connect the wires coming from the 24 VAC power source following the
appropriate diagram below:
One baseboard with a STELPRO RE-153T electronic relay with a 24 VAC
transformer.
Two baseboards, with one connected to a Stelpro RE-153T electronic thermostat with
a 24 VAC transformer, and with the second baseboard connected to a Stelpro RE-153
electronic thermostat without a 24 VAC transformer.

BLACK BLACK
BLACK
BLACK
ELECTRIC RELAY
WITH TRANSFORMER
ELECTRIC RELAY
WITHOUT TRANSFORMER
POWER
WIRES
SIGNALS
BLUE
BLUE
BLUE
RED
WHITE
BLACK BLACK
ELECTRIC RELAY
WITH TRANSFORMER
POWER
WIRES
SIGNALS
BLUE
RED
WHITE


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Standard 24 VAC power source (24 VAC transformer)
NOTE: the color of the wires can change according to the electronic relays that
are used. Connection diagrams in this guide are only examples.
5. Reinstall the front part of the thermostat on the mounting base and tighten the
screw at the bottom of the unit.
6. Turn on the power.
7. Set the thermostat to the desired setting (see the following section).

TRANSFORMER
24 VAC
PRIMARY
SECONDARY
CONTACTOR
OR RELAY

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Intial start up
When powering on for the first time, the thermostat is initially set to Day mode
. The temperature is displayed in Celsius and is set at 21 degrees by default.
Temperature set points
The figures displayed above the pictogram indicate the temperature set point. It can
be displayed in degrees Celsius or Fahrenheit (see “Display in degrees Celsius/
Fahrenheit”).
To adjust the set point, just press down the top button to increase the value, or the
bottom button to decrease it. Set points can be adjusted by increments of 0.5°C
(1°F). To quickly scroll through the set point values, press and hold down the button.
The minimum set point is 3°C (37°F), and the maximum set point is 30°C (86°F). In
Day mode, you can turn off the thermostat by lowering the set point below 3°C. The
set point value displayed will be --.-, and heating system start up will be impossible.
OPERATION
Ambient
temperature
timer
Heating
power
used
indicator
Security mode
Single
programming
mode
Top button
Pictograms
Frost-free
warning
Night mode
Day mode
Bottom button

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Day mode and Night mode
The thermostat includes a Day mode and a Night mode , both of them
having their own independently adjustable and recorded set point. When switching
from one mode to the other, the system will automatically use the temperature set
point corresponding to the Day/Night mode selected. The standard factory set
point adjustment is 21°C (70°F) for the Day mode, and 18°C (64°F) for the Night
mode.
The current Day/Night mode selection is indicated on the display by the Sun or
Moon icon. In order to manually switch from one mode to the other, simultaneously
press down the two buttons and release them immediately.
Night mode timer
The Night mode features a timer that automatically returns to the Day mode after
a selectable time period. This timer allows the temporary use of a temperature set
point. The standard factory adjustment of the timer is 8 hours. With this adjustment,
the thermostat automatically returns to Day mode 8 hours after being switched to the
Night mode.
For example, if you want a night temperature lower than the day temperature, both
Day/Night mode set points will first have to be set at the desired temperatures. Before
bedtime, the Night mode temperature set point will be activated by switching manually
to the Night mode. The timer is set for the duration of the night. The thermostat will
automatically return to the Day mode at the end of the night, and the Day mode
temperature set point, which is higher, will become effective at this time.
Night mode timer adjustment procedure
1. If necessary, adjust the Day/Night mode set points at the desired temperatures.
If needed, switch from one mode to the other by simultaneously pressing down
the two buttons and releasing them immediately.
2. From the Night mode, simultaneously press down the two buttons for more than
3 seconds until the Moon icon blinks.
3. If needed, adjust the timer by pressing down the top button to increase the
value, or the bottom button to decrease it. The adjustment range is from 1
hour to 999 hours. To quickly scroll through timer values, press and hold down
the button.

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4. When the adjustment is completed, release the buttons and wait for 5 seconds
to exit the adjustment function.
NOTE: The Night mode timer will be automatically reinitialized to the latest recorded
value when switching from the Day mode to the Night mode. It is not necessary
to readjust the timer every time you switch to the Night mode. The timer is also
reinitialized when this value is adjusted. Once the timer has completed its cycle
and when the thermostat is in the Day mode, you must manually return to the
Night mode. If you want to automatically return to the Night mode, the Single
programming mode must be selected.
Single programming mode
The Single programming mode, which is associated with the Night mode timer,
allows alternating between the Day/Night modes and the two corresponding set
points over a 24-hour period. Once activated, this mode allows an automatic
return to the Night mode after 24 hours. The Single programming mode allows
you to define two periods in a single day with different set points.
For example, if the Single programming mode is activated and the Night mode
timer is set at 8 hours, the thermostat will be operating in the Night mode for 8
hours at the night temperature set point. Then, it will return to the Day mode for 16
hours operating at the day temperature set point. At the end of the 24-hour cycle,
the thermostat will return to the Night mode, and the cycle will start over. The 24-
hour cycle starts with the Night mode as soon as the Single programming mode
is activated. The Single programming mode activation should be made when you
want to return to the Night mode. The normal course of a cycle in the Single
programming mode is as follows:
1- Night mode: activated for the duration of the Night mode timer cycle. It returns
to the Day mode when the timer cycle is completed.
2- Day mode: activated for the remaining time of the 24-hour cycle. It returns to
the Night mode at the end of the 24-hour cycle.
Adjustment procedure of the Single programming mode:
1. If necessary, adjust the Day/Night set point at the desired temperatures. If
needed, switch from one mode to the other by simultaneously pressing down
the two buttons and releasing them immediately.

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2. From the Night mode, simultaneously press down the two buttons for more
than 3 seconds. If needed, adjust the timer by pressing down the top button to
increase the value, or the bottom button to decrease it. The Night mode timer
adjustment range is from 1 hour to 23 hours in the Single programming mode.
To quickly scroll through the timer values, press and hold the bottom button.
NOTE: If you set the timer to any value exceeding 23 hours, it will be impossible to
activate the Single programming mode and if it was activated, the Single
programming mode will be deactivated.
3. Activate the Single programming mode by simultaneously pressing down
the two buttons for at least 3 seconds. The icon will appear. If the Single
programming mode was already activated, the same procedure should be used
to deactivate it.
4. When the adjustment is completed, release the buttons and wait for 5 seconds
to exit the adjustment function.
NOTE: It is always possible to manually change the Day/Night mode during
a 24-hour cycle. However, any manual return to the Night mode will
re-initialize the Night mode timer to the latest value recorded, which
modifies the cycle in progress. In all cases, at the end of the 24-hour
cycle, the thermostat will return to the Night mode and start a new
cycle. It is thus not necessary to readjust the Single programming
mode when a manual change is made to the Day/Night mode.
When turning back on after being powered off (because of a power
failure, for example), the Single programming mode is deactivated, and, if
previously activated, the icon will blink. The blinking will stop as soon
as you press down a button.
Display in either degrees Celsius/Fahrenheit
The thermostat can display the ambient temperature and the set point in degrees
Celsius (standard factory setting) or Fahrenheit.
1. From the day mode, simultaneously press down the two buttons for 8 seconds
until the Celsius/Fahrenheit symbol blinks. Release the buttons.
2. Press down the top button to switch from the degrees Celsius to the degrees
Fahrenheit, and conversely. The degree Celsius or Fahrenheit symbol will be
displayed.

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3. When the adjustment is completed, release the buttons and wait for 5 seconds
to exit the adjustment function.
Heating Power Indicator
The level of power used to maintain the temperature at the set point is expressed
as a percentage indicated by the number of bars in the thermometer displayed. The
heating power used is displayed as follows:
4 bars = 75% to 100%
3 bars = 50% to 75%
2 bars = 25% to 50%
1 bar = 1% to 25%
0 bar = no heat
Frost-free warning
The Snowflake icon is displayed when the temperature set point is between 3°C
(37°F) and 5°C (41°F). A minimum temperature will be maintained to ensure frost
control.
Security mode
It is possible to impose a maximum temperature set point by activating this
mode. Then, it becomes impossible to exceed this set point, regardless of the
current mode (Day/Night). However, it is still possible to lower the set point at
your discretion.
Procedures to activate the Security mode
1. To activate the Security option, from the Day mode adjust the day set point to the
desired maximum temperature.
2. From the Day mode, simultaneously press down the two buttons for more than 13
seconds, until the icon appears.
3. Release the buttons. The thermostat is now locked.
Procedures to deactivate the Security mode
1. To deactivate the Security mode, start by cutting off the thermostat power at circuit
breaker and wait at least 20 seconds.

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2. Turn the thermostat power back on and the icon will blink for a maximum of 5
minutes.
3. Simultaneously press down both buttons for 13 seconds (note that the backlight
will blink after 3 seconds and the °C or °F symbol will appear after 8 seconds, but
continue to keep both buttons pressed down). After 13 seconds, the icon will
disappear and the degrees symbol (C or F) will stop blinking, indicating that the
Security mode is deactivated. Release the buttons.
Long cycle/Short cycle mode
The Long/Short cycle activation is similar to the Celsius/Fahrenheit degrees
adjustment. To switch from long cycle heating (15 minutes, ideal for a heater with
fan) to a short cycle heating (15 seconds, ideal for a convection heater without
fan), you must simultaneously press down both buttons during 8 seconds in Day
mode. After 8 seconds, the C or F icon will blink. Release the buttons. The screen
then displays CC to indicate short cycle or CL to indicate the long cycle. To switch
from one mode to the other, press down the bottom button. Once the adjustment
done, exit this mode by not pressing down any button for 5 seconds.
Minimum ON/OFF time selection in Long cycle
In Long cycle, you can adjust the minimum ON/OFF time (e.g. the minimum time
between the start and the shut down of the heating). First, activate the Long/
Short cycle mode as described in the previous section. Press down the bottom
button for 3 seconds until the time in seconds appears on the screen. Release
the button. Adjust the minimum time from 90 to 405 seconds, by increments of
45 seconds (factory setting = 180 seconds). Please note that the Long cycle (CL)
is automatically activated when we enter in the minimum ON/OFF time selection
mode. Once the adjustment done, exit this mode by not pressing down any button
for 5 seconds.
Parameters saving and power failures
The thermostat saves some parameters in a non-volatile memory to be able
to recover them after being shut off (a power failure, for example). These
parameters are the Day/Night settings, the Single programming mode, the state
of the Security mode, the maximum symbol of the Security mode, the Celsius/
Fahrenheit symbol, short or long cycle, the number of minutes associated to a
heating cycle, the number of hours of the night time-switch, the number of hours

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remaining on the night time-switch and the current Day/Night mode. These
parameters are saved every minute if any changes are made, except for the Day/
Night mode and the remaining time left on the time-switch. These are saved only
if the Single programming mode had not been activated.
Please note that the Single programming mode is not automatically reactivated
when the thermostat is turned on. The icon blinks to warn the user that the
mode was previously activated when the thermostat was shut off but is no longer
active. Furthermore, when power is shut off, the existing Day/Night mode is
recovered only if the Single programming mode was previously deactivated. In
the opposite case, the Day mode is automatically reactivated. The Security mode
is also reactivated if it was previously activated. However, the icon will blink for
5 minutes, during which it is possible to deactivate the Security mode by pressing
down both buttons simultaneously for 13 seconds. If this is not done, the Security
mode will remain activated and the icon will stop blinking.
Night light (only for model with backlight)
You can activate the Night light option to permanently turn on the backlight. To
activate or deactivate this mode, the thermostat must first be set in Day mode.
Then, simultaneously press down both buttons for 3 seconds until the backlight
blinks. Release the buttons. The night light mode will be activated (or deactivated
if it was previously activated).

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Problem DeFeCTIVe PArT or PArT To CHeCK
Heating is always on
• Check if the thermostat is properly
connected. Refer to the installation
section.
Heating does not run even if the
thermostat indicates it is on
• Check if the thermostat is properly
connected. Refer to the installation
section.
The display does not come on
• Check if the thermostat is properly
connected. Refer to the installation
section. Check the power supply at the
electrical panel. Check if the heating
unit has a switch. If so, ensure that this
switch is turned on.
The displayed ambient
temperature is incorrect
• Check the presence of an air stream or
a heat source near the thermostat, and
correct the situation.
The display indicates E1 or E2 • Faulty thermal sensor. Contact the
customer service.
Weak luminosity of the display
• Possibility of a bad contact. Check
thermostat wirings. Refer to the
installation section.
If you are unable to solve the problem after having veried these points, please
communicate with our customer service. Consult our website for the phone
numbers.
TROUBLESHOOTING

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Supply voltage:
24 VAC, 50/60 Hz
Maximum electrical current
with a resistive load:
0.5 A
12 W @ 24 VAC
Temperature display range:
3 °C to 40 °C (37 °F to 99.5 °F)
Temperature display
resolution:
0.5 °C (0.5 °F)
Temperature set point
range:
3 °C to 30 °C (37 °F to 86 °F)
Temperature set point
increments:
0.5 °C (1 °F)
Storage temperature:
-40 °C to 50 °C (-104 °F to 122 °F)
Inputs / outputs
A 3-positions connector is located at
the back of the thermostat.
C: 24 VAC common
W: Load output
R: 24 VAC input
Compatible with Stepro electronic
relays
TECHNICAL SPECIFICATIONS

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
LIMITED WARRANTY LIMITED WARRANTY
LIMITED WARRANTY LIMITED WARRANTY
LIMITED WARRANTY LIMITED WARRANTY LIMITED WARRANTY LIMITED
LIMITED WARRANTY LIMITED WARRANTY LIMITED WARRANTY LIMITED
LIMITED WARRANTY
This unit has a 3-year warranty. If at any time during this period
the unit becomes defective, it must be returned to its place of
purchase with the invoice copy, or simply contact our customer
service department (with an invoice copy in hand). In order for
the warranty to be valid, the unit must have been installed
and used according to instructions. If the installer or the user
modies the unit, he will be held responsible for any damage
resulting from this modication. The warranty is limited to the
factory repair or the replacement of the unit, and does not cover the
cost of disconnection, transport, and installation.
E-mail: [e-mail]
Web site: www.stelpro.com