1. Introduction
This manual provides detailed instructions for the installation, operation, and maintenance of your KING ES230-R MAX22 Electronic Line Voltage Non-Programmable Thermostat. Please read all instructions carefully before installation and use to ensure proper function and safety.
2. Safety Information
- WARNING: Risk of electrical shock. Disconnect power at the main service panel before installation or servicing.
- Installation must be performed by a qualified electrician in accordance with all local and national electrical codes.
- Do not use this thermostat with loads exceeding its specified rating (22 Amps MAX).
- Ensure all wiring connections are secure and properly insulated.
- This thermostat is designed for line voltage electric heating systems only.
3. Setup and Installation
The KING ES230-R MAX22 thermostat is designed for 3-wire installation, compatible with 208V/240V electric heating systems. It features a shallow design for easier wiring within standard electrical boxes.
3.1 Wiring Diagram
Refer to the diagram provided with your thermostat for specific wiring connections. Generally, it involves one line wire, one load wire, and a third small wire to power the electronic display. Ensure correct polarity and secure connections.
3.2 Mounting
This thermostat is designed for wall mount installation. Secure the thermostat base to a standard electrical box using the provided screws. Ensure the unit is level for optimal appearance.

Front view of the KING ES230-R MAX22 Electronic Line Voltage Non-Programmable Thermostat, showing its digital display with a temperature reading of 70 degrees and the up/down control buttons.
4. Operating Instructions
The ES230-R MAX22 thermostat offers simple, manual temperature control with a clear digital display.
4.1 Setting Temperature
- Use the Up (▲) and Down (▼) arrow buttons located below the display to adjust the desired temperature.
- The thermostat will maintain the set temperature within a narrow range, thanks to its 3-minute cycle rate, which helps reduce temperature swings.
4.2 Display Features
- Comfort Color Backlight: The digital display features a backlight that changes color based on the ambient temperature. It appears blue at 65°F and red at 75°F, with varying colors in between, providing a quick visual indicator of the room's temperature.
- System On/Off Switch: A dedicated switch allows you to turn the heating system on or off.
- Display Illumination On/Off: You can control the illumination of the display independently using a separate switch, useful for bedrooms or areas where constant light is undesirable.
Official product video demonstrating the features and operation of the KING MAX22 Electronic Thermostat, including its 22 Amp rating and display functionalities.
5. Maintenance
The KING ES230-R MAX22 thermostat requires minimal maintenance. It contains no user-serviceable parts. For cleaning, gently wipe the exterior with a soft, damp cloth. Do not use abrasive cleaners or solvents. Ensure the thermostat is kept free from dust and debris to maintain optimal performance.
6. Troubleshooting
- No Display/No Power: Check the circuit breaker for the heating system. Ensure all wiring connections are secure. Verify the third small wire is correctly connected to power the display.
- Incorrect Temperature Reading: Ensure the thermostat is not exposed to direct sunlight, drafts, or heat sources that could affect its sensor. Allow time for the thermostat to acclimate to the room temperature after installation.
- Heating System Not Responding: Confirm the system On/Off switch is in the 'On' position. Check the set temperature to ensure it is above the current room temperature. If issues persist, consult a qualified electrician.
7. Specifications
| Feature | Specification |
|---|---|
| Brand | KING |
| Model Name | MAX22 |
| Part Number | ES230-R |
| Voltage | 208V/240V |
| Amperage (Max) | 22 Amps |
| Wattage (Max) | 5280 Watts (240V) |
| Wiring | 3-Wire Installation |
| Temperature Control Type | Manual |
| Display Type | Digital LCD with Comfort Color Backlight |
| Mounting Type | Wall Mount |
| Product Dimensions | 3 x 1.25 x 5 inches |
| Item Weight | 11.2 ounces |
8. Warranty
The KING ES230-R MAX22 Electronic Line Voltage Non-Programmable Thermostat comes with a 1-year limited warranty. Please retain your proof of purchase for warranty claims. For detailed warranty terms and conditions, refer to the documentation included with your product or contact KING customer support.
9. Support
For technical assistance, troubleshooting, or warranty inquiries, please contact KING customer support. Visit the official KING website for contact information and additional resources.





