1. Introduction
This manual provides detailed instructions for the installation, operation, and maintenance of your KKnoon E21756US Programmable Smart WiFi Thermostat Plug. This device is designed to control heating or cooling appliances via a plug, offering smart control through a mobile application and voice commands. Please read this manual thoroughly before using the product to ensure safe and efficient operation.
2. Safety Information
- Ensure the input voltage and maximum load of the connected appliance do not exceed the thermostat plug's specifications (AC 120V, 60Hz, Max. Load: 10A, Max. Power: 1200W).
- Do not disassemble or modify the device. Unauthorized modifications may cause damage or electric shock.
- Keep the device away from water and high humidity environments.
- The temperature sensor port uses low voltage; however, avoid inserting foreign objects into the port.
- This device is for indoor use only.
- Always unplug the device from the power outlet before cleaning.
- Supervise children to ensure they do not play with the appliance.
3. Package Contents
Verify that all items are present in the package:
- 1 x KKnoon Smart Thermostat Plug (Model E21756US)
- 1 x Temperature Sensor (50cm / 19.7in length)
- 1 x User Manual (English)
4. Product Overview
Familiarize yourself with the components of your smart thermostat plug.

Figure 4.1: Front and back view of the KKnoon Smart Thermostat Plug. The front features the US standard outlet, while the back shows the plug prongs and heat dissipation fins.

Figure 4.2: The smart thermostat plug emphasizing its intelligent control, simple operation, and mobile app remote control capabilities.

Figure 4.3: Dimensions of the KKnoon Smart Thermostat Plug: 70mm (2.76in) height, 64mm (2.52in) width, and 35mm (1.38in) depth.
4.1 Key Components
- Power Outlet: US standard 3-prong outlet for connecting appliances.
- Temperature Sensor Port: 3.5mm jack for connecting the external temperature sensor.
- Wi-Fi Indicator: LED light indicating Wi-Fi connection status.
- Power/Status Indicator: LED light indicating power and operational status.
- Reset Button: Used for pairing and resetting the device (location typically on top or side).
5. Specifications
| Feature | Specification |
|---|---|
| Model Name | E21756US |
| Input Voltage | AC 120V, 60Hz |
| Max. Load | 10A |
| Max. Power | 1200W |
| Temperature Measurement Range | -20~100℃ / -4~212℉ |
| Temperature Sensor Length | 50cm / 19.7in |
| Wi-Fi Requirement | 2.4GHz Wi-Fi only |
| APP Compatibility | 'Smart Life' App |
| System Support | Android / iOS |
| Voice Control | Compatible with Amazon Alexa, Google Assistant |
| Material | ABS |
| Item Size | 70 * 64 * 35mm / 2.76 * 2.52 * 1.38in |
6. Setup
6.1 App Installation
- Download the 'Smart Life' app from the Apple App Store (for iOS) or Google Play Store (for Android). You can search for "Smart Life" or scan the QR code provided in the quick start guide (if applicable).
- Register an account or log in if you already have one.
6.2 Device Pairing (Wi-Fi Connection)
- Plug the KKnoon Smart Thermostat Plug into a standard US wall outlet.
- Insert the temperature sensor into the 3.5mm port on the thermostat plug.
- Open the 'Smart Life' app. Tap the "+" icon in the top right corner to add a device.
- Select "Electrical" then "Socket (Wi-Fi)" or search for "Thermostat Plug".
- Follow the in-app instructions to put the device into pairing mode. This usually involves pressing and holding the reset button on the plug until the Wi-Fi indicator light blinks rapidly.
- Enter your 2.4GHz Wi-Fi network password. Ensure your smartphone is connected to the same 2.4GHz Wi-Fi network. Note: The device does not support 5GHz Wi-Fi networks.
- Wait for the app to connect to the device. Once connected, you can rename the device for easier identification.

Figure 6.1: Example of the 'Smart Life' app interface for setting weekly temperature schedules for the thermostat plug.

Figure 6.2: The smart thermostat plug connected to its temperature sensor, illustrating its Wi-Fi, timer, app control, and thermostat functions.
7. Operating Instructions
7.1 Basic Operation
- Plug your heating or cooling appliance into the thermostat plug's outlet.
- The thermostat plug will automatically detect the current ambient temperature via its connected sensor.
- The device can be manually turned ON/OFF via the physical button (if available) or primarily controlled through the 'Smart Life' app.
7.2 App Control
The 'Smart Life' app provides comprehensive control over your thermostat plug:
- Remote ON/OFF: Turn the connected appliance on or off from anywhere using your smartphone.
- Temperature Setting: Set your desired target temperature. The plug will automatically turn the appliance on or off to maintain this temperature.
- Scheduling: Create custom schedules for different times of the day and days of the week. For example, set a lower temperature when you are away and a comfortable temperature before you return.
- Countdown Timer: Set a countdown timer for the appliance to turn on or off.
- Temperature Unit: Switch between Celsius (℃) and Fahrenheit (℉) within the app settings.
- Mode Selection: Choose between heating or cooling modes depending on your appliance and needs.
7.3 Voice Control
The thermostat plug is compatible with Amazon Alexa and Google Assistant. To enable voice control:
- Link your 'Smart Life' account to your Alexa or Google Home app.
- Discover devices in your Alexa/Google Home app.
- Use voice commands such as:
- "Alexa, turn on [Device Name]"
- "Hey Google, set [Device Name] to 22 degrees"
- "Alexa, what is the temperature of [Device Name]?"
8. Maintenance
- Cleaning: Unplug the device before cleaning. Use a soft, dry cloth to wipe the surface. Do not use liquid cleaners or sprays.
- Storage: If not in use for an extended period, unplug the device and store it in a cool, dry place.
- Sensor Care: Ensure the temperature sensor is kept clean and free from obstructions for accurate readings. Avoid bending or damaging the sensor cable.
9. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Device cannot connect to Wi-Fi. | Incorrect Wi-Fi password; 5GHz Wi-Fi network; device too far from router; incorrect pairing mode. |
|
| Appliance not turning ON/OFF as expected. | Incorrect temperature setting; wrong mode (heating/cooling); appliance not powered on; thermostat plug not receiving power. |
|
| Temperature readings are inaccurate. | Sensor not properly connected; sensor placed in an unsuitable location; damaged sensor. |
|
| Voice control not working. | 'Smart Life' account not linked; device not discovered; incorrect voice commands. |
|
10. Warranty and Support
KKnoon products are designed and manufactured to the highest quality standards. For warranty information, technical support, or customer service inquiries, please refer to the contact information provided on the product packaging or visit the official KKnoon website. Please have your model number (E21756US) and purchase date available when contacting support.
For further assistance, you may visit the KKnoon Store on Amazon.