Stelpro STE252NP+ User manual

Energy Veried
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USER’S GUIDE
STE252NP+
SINGLE PROGRAMMING
ELECTRONIC THERMOSTAT
For further information or to consult this guide online,
please visit our website at www.stelpro.com
INSSTE252NP+0414

2INSSTE252NP+0414
WARNING
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. All electric connections must be made by
         
effective in your region. Do NOT connect this product to a supply
source other than 120 VAC or 240 VAC, and do not exceed the load limits

or fuse. You must regularly clean dirt accumulations on the thermostat.

a wet place. However, installing it in isolated walls is allowed.
Note:
When a part of the product specification must be changed to improve operability
or other functions, priority is given to the product specification 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.

3INSSTE252NP+0414
The electronic thermostat STE252NP with or without backlight (indicated by a
+ at the end of the code) can be used to control electric heating units such as
electric baseboards, convectors, or aeroconvectors. It keeps the temperature of
a room at the requested set point with a high degree of accuracy. This product
is designed for installations with electrical current - with a resistive load - ranging
from 1.25 A to 10,4 A (120/240 VAC). It possesses a user-friendly interface.
Furthermore, it gives you the possibility to control the temperature of a room with
great precision.
This thermostat is not compatible with the following
installations:
• electrical current higher than 10,4 A with a resistive load (2500 W @ 240 VAC
and 1500 W @ 120 VAC);
• electrical current lower than 1.25 A with a resistive load (300 W @ 240 VAC and
150 W @ 120 VAC); and
• central heating system.
Parts supplied:
• one (1) thermostat;
• wall mounting plate located at the back of the thermostat;
• two (2) mounting screws;
• two (2) solderless connectors suitable for copper wires.
Selection of the thermostat location
The thermostat must be mounted to a connection box on a wall facing the heating
unit, at around 1.5 m (5 feet) above the floor 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:
DESCRIPTION
INSTALLATION

4INSSTE252NP+0414
• 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 fireplace or any other
heat source;
• close or in front of an air outlet;
• close to concealed ducts or a chimney; and
• in a location with poor air flow (e.g. behind a door), or with frequent air drafts
(e.g. head of stairs).
Thermostat mounting and connection
1. Cut off power supply on lead wires at the electrical panel in order to avoid any
risk of electric shock.
2. Ensure that the air vents of the thermostat are clean and clear of any
obstruction.
3. Using a screwdriver, loosen the screw retaining the mounting base of the
thermostat until you feel a loose (do not completely remove the screw).
Then, remove the mounting base at the back of the thermostat by tilting it
downward, then towards you.
4. Align and secure the mounting base to the connection box using the two screws
supplied.

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5. Pass the wires from the wall through the hole at the base of the mounting base
and connect them using the supplied solderless connectors. When making
the connection with aluminum wire, make sure that you are using connectors
identified CO/ALR. Please note that the thermostat wires do not have polarity.
Therefore, the way they are connected is not important.
2-WIRE INSTALLATION
4-WIRE INSTALLATION

6INSSTE252NP+0414
6. Place all the wires into the connection box.
7. Align the notch on the top of the thermostat with the wall plate. Then, tighten the
screw at the bottom of the unit.
8. Turn on the power.
9. Set the thermostat to the desired setting (see the following section).
Alignment

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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.
Ambient temperature/
timer
Heating power
indicator
Single programming mode
Security mode
Fan mode
Top button
Pictograms
Frost-free warning
Day mode
Night mode
Bottom button
OPERATION

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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.
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.

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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.
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.

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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.
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

11 INSSTE252NP+0414
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.

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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 3 seconds.
The Celsius/Fahrenheit symbol will blink after 3 seconds. (For the backlit
models, press down the two buttons for 8 seconds. Note that the backlight
will blink after 3 seconds, but you must hold down the buttons. The Celsius/
Fahrenheit symbol will blink after 8 seconds.) 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.
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

13 INSSTE252NP+0414
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 (note that the °C or °F symbol will blink after
3 seconds, but continue to keep both buttons pressed down). (For the backlit
models, 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).
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.
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.
Fan mode
The activation of the Fan mode is similar to the Celsius/Fahrenheit adjustment.
To activate or deactivate the Fan mode, you must press down both buttons
simultaneously for 3 seconds while in Day mode. Once the 3 seconds have
passed, the Celsius/Fahrenheit symbol will blink. (For the backlit models, press
down both buttons for at least 3 seconds in Day mode. Note that the backlight
will blink after 3 seconds but hold down the buttons until the Celsius/Fahrenheit

14 INSSTE252NP+0414
symbol blinks.) At this point, release the buttons. You must then press down the
bottom button to activate or deactivate the Fan mode. The Fan pictogram will turn
on or off depending on the case.
When the Fan mode is activated, the stop or minimum heating time (off/on) for
a complete 10 minute cycle is established at 90 seconds (factory setting). You
can adjust it from 90 to 300 seconds. This is done to limit the amount of times
the thermostat will turn on or off. Also, if the thermostat reaches a differential
superior or inferior to the 2 degrees requested, it will shut off immediately. The
deactivation of the Fan mode will cause the thermostat to go back to the heating
cycle previously programmed. Once the adjustment is finished, you can exit the
adjustment mode by not pressing any buttons for 5 seconds.
Ventilation intervals duration
You can adjust the minimum time between the fan startups and shutdowns. This
adjustment is similar to the fan activation procedure. First, you have to enter the
fan adjustment mode, as described in the previous section. Then, you must press
down the bottom button for 3 seconds, until the icon blinks. A duration in
seconds will appear. You can adjust it from 90 (factory setting) to 300 seconds
by increments of 30 seconds. Once the adjustment is done, you can exit the
adjusment mode by not pressing down any button during 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, the Fan mode, the number of minutes associated to a heating
cycle, the number of hours of the night time-switch, the number of hours 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

15 INSSTE252NP+0414
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).

16 INSSTE252NP+0414
PROBLEM DEFECTIVE PART OR PART TO CHECK
The thermostat is hot.
• In normal operating conditions, the thermostat
housing can reach nearly 40°C at maximum load.
That is normal and will not affect the effective
operation of the thermostat.
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
turn 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 display turns off a
few minutes and then
turns on again.
• The thermal protection of the heating unit has
opened due to overheating. Check if the heating
unit is in good condition of operation and that
clearance around the appliance is according to
the manufacturer’s specifications.
The display has low
contrast when heating
is on.
• The load is lower than the minimum load. Install
a heating unit that is within the load limits of the
thermostat.
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.
N.B. 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

17 INSSTE252NP+0414
TECHNICAL SPECIFICATIONS
Supply voltage:
120/208/240 VAC, 50/60 Hz
Minimum electrical current with a resistive load:
1.25 A
150 W @ 120 V
260 W @ 208 V
300 W @ 240 V
Maximum electrical current with a resistive load:
10.4 A
1250 W @ 120 VAC
2160 W @ 208 VAC
2500 W @ 240 VAC
Temperature display range:
3 °C à 40 °C (37 °F à 99,5 °F)
Temperature display resolution:
0,5 °C (0,5 °F)
Temperature set point range:
3 °C à 30 °C (37 °F à 86 °F)
Temperature set point increments:
0,5 °C (1 °F)
Storage temperature:
-40 °C à 50 °C (-104 °F à 122 °F)

18 INSSTE252NP+0414
LIMITED WARRANTY LIMITED WARRANTY LIMITED WARRANTY
LIMITED WARRANTY LIMITED WARRANTY LIMITED WARRANTY
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
LIMITED WARRANTY LIMITED WARRANTY LIMITED
LIMITED WARRANTY LIMITED WARRANTY LIMITED
 | Saint-Bruno-de-Montarville | Québec | J3V 6L7