Stelpro STE402NP+ Electronic Thermostat User Guide

Important Safety Information

WARNING: Before installing or using this product, read and understand these instructions and keep them for future reference. Failure to comply with these directives may result in personal injury, property damage, serious injury, and potentially fatal electric shock. Electrical connections must be made by a qualified electrician according to local electrical and building codes. Do not connect the unit to a power source other than 120/240 VAC and respect load limits. Protect the heating system with appropriate circuit breakers or fuses. Regularly clean accumulated dirt from the unit. Do not use liquid to clean the thermostat's ventilation openings. Do not install the thermostat in a wet location, but installation on insulated walls is permitted.

Note: Product features may be modified to improve usability. The manual may not fully correspond to all product functions. The product, packaging, name, and illustrations may differ from those presented in this manual. The LCD display shown may differ from the actual display.

Description

The STE402NP+ electronic thermostat with or without backlight is designed to control electric heaters (with or without a fan) with a resistive load between 1.25 A and 16.7 A under a 120/240 VAC voltage. It features a user-friendly interface and allows for precise room temperature control.

Incompatible Installations:

• Resistive load current exceeding 16.7 A (4000W @ 240 VAC and 2000W @ 120 VAC)
• Resistive load current below 1.25 A (300 W @ 240 VAC and 150 W @ 120 VAC)
• Central heating systems

Included Parts:

• One (1) thermostat
• Wall mounting plate (at the back of the thermostat)
• Two (2) mounting screws
• Two (2) solderless connectors for copper wire connection

Installation

Choosing the Thermostat Location

The thermostat should be installed on an electrical box, approximately 1.5 m (5 feet) from the floor, on a wall section without pipes or air ducts. Avoid locations that can falsify temperature readings:

• Near a window, on an exterior wall, or near a door leading outside.
• Directly exposed to sunlight, lamps, fireplaces, or other heat sources.
• Near or in front of an air vent.
• Near concealed ducts or a chimney.
• In an area with poor air circulation, such as behind a door, or with frequent drafts, such as at the top of a staircase.

Mounting and Wiring the Thermostat

1. Cut off the power supply from the circuit breaker to avoid the risk of electric shock.
2. Ensure the thermostat's ventilation openings are clean and unobstructed.
3. Using a screwdriver, loosen the screw at the base of the thermostat until you feel it release (do not remove the screw completely).

Remove the wall plate from the back of the thermostat by pulling it down, then towards you.

4. Attach the wall plate to the electrical box using the two provided screws.
5. Pass the wires from the wall through the hole in the wall plate and make the electrical connections using the provided solderless connectors. For aluminum wires, use CO/ALR connectors. The thermostat wires have no polarity; connection direction does not matter.

Wiring Diagrams:

2-Wire Installation: [Diagram showing 2-wire connection]

4-Wire Installation: [Diagram showing 4-wire connection]

6. Place all wires inside the electrical box.
7. Align the notches on the top of the thermostat with those on the wall plate. The thermostat can be positioned to the left or right of the junction box as needed. Snap the thermostat into the wall plate by sliding it down, then retighten the screw at the base of the unit.

Alignment: [Image showing thermostat alignment]

8. Turn on the installation power.
9. Adjust the thermostat to your preferences (see the following section).

Operation

Pictograms:

[Diagram of thermostat display with labels for ambient temperature, heating power indicator, frost warning, day mode, night mode, fan mode, unique programming mode, security mode, up button, down button]

First Power-Up

Upon first power-up, the thermostat is in Day mode ☀️. The temperature is displayed in Celsius, and the default setpoint is 21°C.

Temperature Setpoint

The temperature setpoint is displayed above the pictograms and can be shown in Celsius or Fahrenheit. To adjust the setpoint, press the up button to increase and the down button to decrease. Adjustments are in 0.5°C (1°F) increments. For rapid scrolling, hold the desired button. The minimum setpoint is 3°C (37°F) and the maximum is 30°C (86°F). Pressing a button displays the current temperature setpoint and the corresponding pictogram (sun or moon) flashes. To return to ambient temperature, do not press any button for 3 seconds or press both buttons simultaneously. In Day mode, the thermostat can be turned off by lowering the setpoint below 3°C (37°F), indicated by --.-.

Day and Night Mode ☀️?

The thermostat has a Day mode and a Night mode, each with its own adjustable and memorized setpoint. The ambient temperature is displayed in Celsius or Fahrenheit. When switching modes, the corresponding setpoint is automatically used. The default setpoint is 21°C (70°F) for Day mode and 18°C (64°F) for Night mode. To manually switch modes, press and release both buttons simultaneously within three seconds.

Night Mode Timer

The Night mode includes a timer for automatic return to Day mode after an adjustable delay. The default timer is 8 hours, after which the thermostat automatically returns to Day mode. If you want a lower night temperature, adjust the Day/Night setpoints accordingly. Before sleeping, activate the Night mode setpoint. The timer is adjusted based on the desired night duration. The thermostat will automatically return to Day mode at the end of the night, and the higher Day mode setpoint will become effective.

Night Mode Timer Adjustment Procedure

1. Switch to Night mode by pressing and releasing both buttons simultaneously within three seconds.
2. In Night mode, press and hold both the up and down buttons for more than 3 seconds. The moon pictogram flashes, and the current timer adjustment is displayed.
3. Adjust the timer by pressing the up button to increase and the down button to decrease. The adjustment can range from 1 to 999 hours. For rapid scrolling, hold the button.
4. Once the adjustment is complete, release the buttons and wait 5 seconds to exit the adjustment mode. The thermostat will return to Night mode.

Note: The Night mode timer automatically reverts to the last adjusted value when switching from Day to Night mode. The timer is also reset each time it is adjusted. If the timer expires in Day mode, manual switching to Night mode is required. For automatic return to Night mode, Unique Programming mode must be activated.

Unique Programming Mode ?

Unique Programming mode, combined with the Night mode timer, allows alternating between Day/Night modes and their respective setpoints over a 24-hour period. Once activated, this mode enables automatic return to Night mode after 24 hours. It allows setting two different setpoints for a 24-hour period. For example, if Unique Programming mode is active with an 8-hour Night mode timer, the thermostat will be in Night mode for 8 hours, then in Day mode for the remaining 16 hours. After 24 hours, the cycle restarts with Night mode. The 24-hour cycle begins in Night mode upon activation of Unique Programming mode. Activation should occur at the time you wish the Night mode to begin.

Normal Cycle in Unique Programming Mode:

1. Night Mode: Active for the duration of the Night mode timer. Returns to Day mode at the end of the timer.
2. Day Mode: Active for the remaining time in the 24-hour cycle. Returns to Night mode at the end of the 24-hour cycle.

Unique Programming Mode Adjustment Procedure

1. Switch to Night mode by pressing and releasing both buttons simultaneously within three seconds.
2. In Night mode, press and hold both the up and down buttons for more than 3 seconds. Adjust the Night mode timer from 1 to 23 hours. Holding the button allows rapid scrolling. Note: A timer value of 23 hours or more disables Unique Programming mode or deactivates it if it was already active.
3. Activate Unique Programming mode by pressing and holding both buttons for at least 3 seconds. The ? icon will appear. If the mode was already active, this procedure deactivates it.
4. Once adjustment is complete, release the buttons and wait 5 seconds to exit the adjustment function.

Note: Even in Unique Programming mode, manual switching between Day and Night modes is possible and does not affect the 24-hour cycle or automatic return to Night mode. Switching to OFF mode (--.-) deactivates Unique Programming mode.

When power is restored after an outage, Unique Programming mode is deactivated. If it was previously active, the ? icon will flash until a button is pressed. The icon will stop flashing once a button is pressed.

Celsius/Fahrenheit Display

The thermostat can display ambient temperature in Celsius (factory setting) or Fahrenheit. To switch between Celsius and Fahrenheit:

1. Ensure the thermostat is in Day mode. Press and hold both buttons for 3 seconds. The °C or °F symbol will flash; release the buttons. (For backlit models, hold for 8 seconds; the backlight flashes after 3 seconds, but keep holding the buttons.)
2. Press the up button to switch from Celsius to Fahrenheit, or vice versa. The corresponding °C or °F symbol will appear on the display.

Once the adjustment is complete, do not press any button for 5 seconds to exit.

Heating Power Used

The heating power level used to maintain the temperature setpoint is indicated by vertical bars next to the temperature setpoint. The heating power is read as follows:

• 4 bars = 75% to 100%
• 3 bars = 50% to 75%
• 2 bars = 25% to 50%
• 1 bar = 1% to 25%
• 0 bars = no heating

Frost Warning ❄️

The snowflake icon ❄️ is displayed when the temperature setpoint is between 3°C (37°F) and 5°C (41°F). A minimum temperature is maintained to ensure frost protection.

Security Mode ?

This mode allows setting a maximum temperature setpoint, preventing it from being exceeded regardless of the current mode. However, the temperature can still be lowered at will.

Security Mode Activation Procedure:

1. To activate Security mode, be in Day mode and set the Day setpoint to the desired maximum value.
2. Press and hold both buttons simultaneously for 13 seconds. (Note: After 3 seconds, the °C or °F symbol will flash; continue holding both buttons. For backlit models, the backlight flashes after 3 seconds, and the °C or °F symbol flashes after 8 seconds; continue holding both buttons.)
3. After 13 seconds, the ? icon will appear, and the °C or °F symbol will stop flashing, indicating that Security mode is active. Release the buttons.

Security Mode Deactivation Procedure:

1. To deactivate Security mode, first turn off the thermostat's power at the circuit breaker and wait at least 20 seconds.
2. Restore power to the thermostat. The ? icon will flash for a maximum of 5 minutes, indicating that Security mode can be deactivated.
3. Press and hold both buttons simultaneously for over 13 seconds. (Note: After 3 seconds, the backlight flashes; after 8 seconds, the °C or °F symbol flashes; continue holding both buttons.) After 13 seconds, the ? icon will turn off, and the °C or °F symbol will stop flashing, indicating that Security mode is deactivated. Release the buttons.

Fan Mode ?

Activating Fan mode is similar to adjusting Celsius/Fahrenheit. To activate or deactivate Fan mode, press both buttons simultaneously in Day mode. The °C or °F symbol will flash after 3 seconds. (For backlit models, press both buttons for at least 3 seconds in Day mode; the backlight flashes after 3 seconds, but keep holding the buttons until the °C or °F symbol flashes.) Release the buttons. Press the down button to activate or deactivate Fan mode. The fan pictogram will turn on or off accordingly.

When Fan mode is active, the minimum off/heating time (on/off cycle) for a 10-minute period is set to 90 seconds by default. This is adjustable from 90 to 300 seconds to limit frequent starts/stops of the appliance. Heating can also be stopped by lowering the temperature setpoint. Additionally, if the thermostat reaches a differential of 2 degrees, it will stop before the minimum heating time is reached, adjustable from 90 to 300 seconds.

Once adjustment is complete, exit adjustment mode by not pressing any button for 5 seconds.

Ventilation Interval Adjustment

The minimum time between fan starts and stops can be adjusted. This adjustment is similar to activating Fan mode. First, enter the Fan mode adjustment as described previously. Then, press and hold the down button for 3 seconds until the fan pictogram flashes. The display will show a duration in seconds. This duration can be adjusted between 90 seconds (default) and 300 seconds in 30-second increments. Once adjustment is complete, exit by not pressing any button for 5 seconds.

Saving Parameters and Power Outages

The thermostat saves certain parameters in non-volatile memory for retrieval after a power outage. These parameters include: Day/Night setpoints, Unique Programming mode status, Security mode status, Security mode maximum setpoint, Celsius/Fahrenheit mode, Fan mode, minimum on/off time in Fan mode, Night mode timer hours, remaining Night mode timer hours, and current Day/Night mode. These parameters are saved every minute if a modification occurred, except for Day/Night mode and remaining timer time, which are saved only if Unique Programming mode was not active.

Note: Unique Programming mode is not automatically reactivated upon power-up. The ? icon flashes to warn the user that this mode was previously active but is now deactivated. Upon power-up, the current Day/Night mode is restored only if Unique Programming mode was previously deactivated. Otherwise, Day mode is automatically reactivated. Security mode is also reactivated if it was active before the power outage. However, its icon flashes for 5 minutes, during which Security mode can be deactivated by pressing both buttons simultaneously for 13 seconds. Otherwise, Security mode remains active, and the icon stops flashing.

Standby Mode (for backlit models only)

If you wish the backlight to remain continuously illuminated, you can activate Standby mode. To activate or deactivate this mode, the thermostat must be in Day mode. Press and hold both buttons for 3 seconds until the backlight flashes, then release the buttons. Standby mode will then be activated or deactivated.

Troubleshooting

If you cannot resolve the problem after checking these points, please contact customer service (refer to the website for phone numbers).

Technical Specifications

• Power Supply Voltage: 120/208/240 VAC, 50/60 Hz
• Minimum Current with Resistive Load: 1.25 A (150 W @ 120 V, 260 W @ 208 V, 300 W @ 240 V)
• Maximum Current with Resistive Load: 16.7 A (2000 W @ 120 VAC, 3470 W @ 208 VAC, 4000 W @ 240 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 Setpoint Range: 3°C to 30°C (37°F to 86°F)
• Temperature Setpoint Increments: 0.5°C (1°F)
• Storage: -40°C to 50°C (-104°F to 122°F)