1. Introduction
Thank you for choosing the MIUCDA Tuya WiFi Smart Thermostat. This device is designed to provide intelligent temperature control for various heating systems, including electric floor heating, water heating, and water/gas boilers. With its touch-button interface, LED screen, and smart connectivity via Tuya Smart Life app, you can manage your home's climate from anywhere, anytime. It also supports voice control through popular smart assistants like Amazon Alexa and Google Home.
Figure 1: Front view of the MIUCDA Tuya WiFi Smart Thermostat.
2. Safety Information
Please read this manual carefully before installation and operation. Improper installation or use can lead to electric shock, fire, or damage to the device. Always follow local electrical codes and regulations.
- Installation should only be performed by a qualified electrician.
- Ensure power is disconnected at the circuit breaker before installation or maintenance.
- Do not expose the thermostat to water or excessive humidity.
- Do not attempt to repair or modify the device yourself. Contact qualified personnel for service.
- Keep packaging materials out of reach of children.
3. Package Contents
Verify that all items are present in your package:
Figure 2: Package contents for different thermostat versions.
| Item | Electric Floor Heating (16A) | Water/Gas Boiler (3A) | Water Heating (3A) |
|---|---|---|---|
| Thermostat | ✔ | ✔ | ✔ |
| Packing box | ✔ | ✔ | ✔ |
| Instructions | ✔ | ✔ | ✔ |
| Screws (x2) | ✔ | ✔ | ✔ |
| External sensor (3m) | ✔ | ✖ | ✖ |
4. Specifications
| Feature | Detail |
|---|---|
| Model Number | WT400S |
| Type | WiFi Smart Thermostat |
| Color Options | White/Black |
| Voltage | 100-240V AC, 50/60HZ |
| Max. Current Load | 16A (Electric Heating), 3A (Water Heating/Water Gas Boiler) |
| Temperature Accuracy | 1℃ |
| Temperature Setting Range | 5-35℃ |
| Temperature Hysteresis | 0.5~3℃ |
| Minimum Temperature Setting | 0.5℃ |
| Key Type | Press Key (Touch button) |
| Item Size | 86 x 86 x 14mm (front panel) |
| App Compatibility | Tuya Smart Life |
| Voice Control | Amazon Alexa, Google Home, Yandex Alice |
| Certification | CE |
Figure 3: Product dimensions (86mm x 86mm x 14mm front, 26mm depth).
5. Installation
5.1 Wiring Diagrams
Ensure the main power supply is turned OFF before attempting any wiring. Connect the thermostat according to the specific wiring diagram for your heating system type. Incorrect wiring can damage the thermostat and heating system, and poses a safety risk.
Electric Floor Heating (16A)
Figure 4: Wiring for Electric Floor Heating (16A). Connect Live wire to L1, Neutral wire to N1, and Load to terminals 3 and 4. The external sensor connects to terminals 1 and 2.
Water/Gas Boiler (3A)
Figure 5: Wiring for Water/Gas Boiler (3A). Connect Live wire to L, Neutral wire to N, and Dry Contact to terminals 3 and 4.
Water Heating (3A) - NC Type
Figure 6: Wiring for Water Heating (3A) NC Type. Connect Live wire to L, Neutral wire to N, and NC (Normally Closed) to terminals 3 and 4.
Water Heating (3A) - NO Type
Figure 7: Wiring for Water Heating (3A) NO Type. Connect Live wire to L, Neutral wire to N, and NO (Normally Open) to terminals 3 and 4.
5.2 Physical Installation
- Turn off the main power supply to your heating system.
- Mount the backplate of the thermostat to a standard wall junction box using the provided screws.
- Connect the wires according to the appropriate wiring diagram for your heating system.
- Carefully attach the thermostat display unit to the mounted backplate, ensuring it clicks securely into place.
- Restore power to the heating system.
5.3 App Setup (Tuya Smart Life)
- Download the "Tuya Smart" or "Smart Life" app from your smartphone's app store (iOS or Android).
- Register or log in to your account.
- Add a new device: Follow the in-app instructions to add a new thermostat. This typically involves putting the thermostat into pairing mode (refer to the thermostat's display for pairing indicators, usually a flashing WiFi icon).
- Connect the thermostat to your home's 2.4GHz WiFi network.
- Once connected, you can control the thermostat remotely via the app.
6. Operation
6.1 Basic Controls
The thermostat features a touch-button interface and an LED screen for clear display of information and easy interaction.
6.2 Operating Modes
The thermostat offers two primary operating modes: Manual mode and Program mode.
Figure 8: App interface showing selection between Manual and Program modes.
- Manual Mode: Set a desired temperature, and the thermostat will maintain that temperature until manually changed.
- Program Mode: Allows for scheduled temperature settings throughout the day and week.
Programming Mode
The programming mode supports 5+2, 6+1, or 7-day schedules, with up to 6 time-modes daily. This allows for customized temperature settings to match your weekly routine.
Figure 9: Example of programming mode for weekly temperature scheduling.
Additionally, there are four selection modes for programming: Closed, Weekend, Single Holiday, and No Holiday, offering flexibility for different scenarios.
6.3 Advanced Features
- Backlight Brightness Adjustable: The backlight brightness can be adjusted or turned off completely to avoid disturbing sleep. This setting can be controlled via the app by percentage.
- Temperature Calibration: Adjust the displayed temperature to match an external reference thermometer. The calibration range is from -9.9°C to 9.9°C.
- Sensor Selection: Choose between Internal Sensor, External Sensor, or Both Sensors. When both sensors are used, the thermostat displays the average temperature. The minimum temperature limit for the internal sensor is 5°C, and the maximum temperature limit for the external sensor is 70°C.
- Children Lock: A locking function designed to prevent accidental operation by children. This can be activated via the app.
- Voice Control: The thermostat works with Amazon Alexa, Google Home, and Yandex Alice, allowing you to adjust settings using voice commands.
- Group-Control Function: Realize group control for multiple thermostats in different rooms within a special scene, allowing for synchronized temperature management.
- Family Share Function: Create a smart home together by sharing control of the thermostat with family members through the app.
Figure 10: Adjusting backlight brightness via the app.
Figure 11: Temperature calibration settings in the app.
Figure 12: Sensor selection options in the app.
Figure 13: Child Lock feature activated via the app.
Figure 14: Voice control example with Alexa and Google Home.
Figure 15: Group control setup in the app for managing multiple thermostats.
Figure 16: Family sharing feature in the app.
7. Maintenance
- Cleaning: Wipe the thermostat's screen and body with a soft, dry cloth. Do not use abrasive cleaners, solvents, or chemical sprays.
- Software Updates: Keep your Tuya Smart Life app updated to ensure the best performance and access to new features. Firmware updates for the thermostat may be pushed through the app.
- Regular Checks: Periodically check the wiring connections to ensure they are secure.
8. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Thermostat not powering on | No power supply; incorrect wiring; circuit breaker tripped. | Check circuit breaker. Verify wiring connections. Consult an electrician if unsure. |
| Heating system not responding | Incorrect wiring; thermostat in wrong mode; heating system fault. | Check wiring. Ensure thermostat is in heating mode and set temperature is above ambient. Check heating system for faults. |
| WiFi connection unstable/disconnected | Weak WiFi signal; incorrect WiFi password; router issues. | Ensure thermostat is within WiFi range. Re-enter WiFi password in app. Restart router. Ensure 2.4GHz network is used. |
| Inaccurate temperature reading | Sensor calibration needed; sensor fault; thermostat exposed to direct heat/cold. | Use the Temperature Calibration feature in the app. Ensure thermostat is not near heat sources or drafts. Check external sensor connection if applicable. |
| Voice control not working | Incorrect setup with Alexa/Google Home; app not linked; voice command error. | Verify the Tuya/Smart Life skill is enabled and linked in your smart assistant app. Use correct voice commands. Check internet connection. |
9. User Tips
- Optimize Programming: Take advantage of the 5+2/6+1/7-day programming to create energy-efficient schedules that match your daily routine, reducing energy consumption when you're away or asleep.
- Utilize Child Lock: If you have young children, enable the child lock feature through the app to prevent accidental changes to your heating settings.
- Consider External Sensor: For floor heating systems, using the external sensor can provide more accurate floor temperature readings and better comfort control.
- Group Control for Zones: If you have multiple thermostats in different rooms, use the group control function to manage them collectively for consistent heating across zones.
- Regular App Checks: Periodically check the Tuya Smart Life app for new features or firmware updates that can enhance your thermostat's functionality and performance.
10. Warranty and Support
For any technical assistance, troubleshooting beyond this manual, or warranty inquiries, please contact the seller or manufacturer directly. Keep your purchase receipt as proof of purchase.