ESP32 Opentherm Gateway
ESP32 OpenTherm Gateway – Smart Heating Integration with Home Assistant
The ESP32 OpenTherm Gateway is a smart home device designed to interface OpenTherm-compatible boilers with Home Assistant, facilitating real-time monitoring and control over heating systems.
Built around the ESP32-WROOM-32U microcontroller, it offers Wi-Fi connectivity and is fully compatible with ESPHome, enabling seamless integration.
- Integrates OpenTherm heating systems into Home Assistant via ESPHome
- Supports OpenTherm protocol for boiler communication
- Ideal for DIY smart heating automation and remote thermostat control
- DIN-rail mountable with 24VDC/220VAC power and onboard ESP32 microcontroller
- Open-source firmware and schematics available on GitHub
Integration and Control:
The gateway leverages ESPHome for configuration and supports over-the-air (OTA) updates, ensuring ease of maintenance and customization. It integrates with Home Assistant, providing users with the ability to automate and monitor various aspects of their heating systems, such as:
- Burner status (on/off)
- Flame modulation levels
- System pressure readings
- Current and return water temperatures
- Domestic hot water (DHW) status and temperature
Display Name:
ESP32 Opentherm Gateway
Function
It acts as a bridge between your heating system and Home Assistant, allowing real-time monitoring and adjustment of parameters like target temperature, boiler status, flame modulation, and more. The setup is compact, Wi-Fi-enabled, and leverages the ESPHome platform for easy configuration, OTA updates, and seamless integration into your smart home ecosystem.
Key Features
-
Controller
ESP32-Wroom-32U -
Designed special for ESPHome.
All elements of the Gateway are fully compatible with ESPHome, ensuring optimal integration. -
Input Voltage
24V DC or 120VDC - 370VDC, 85VAC - 265VAC/47 - 63Hz -
Built-in USB Interface
For programming and debugging -
Build-in Relay
For supplementary equipment management -
2x1-Wire
For extra temperature measurement
Gateway Capabilities:
-
Opentherm
An Opentherm bus interface for managing heating equipment that supports the Opentherm protocol. -
1-WIRE
Two channels designed for 1-Wire bus communication, featuring ESD and overvoltage protection to improve reliability. -
Relay
One high-performance industrial relay for control applications, equipped with varistor protection for enhanced reliability. The relay are optically isolated from the MCU.
-
LEDs and Buttons
Customizable button positioned on the front panel, along with LED indicators for displaying status on the front panel. -
WiFi and BT
Integrated into the ESP32's WiFi capabilities -
USB
USB Type-C port for programming purposes.
Electrical Data
-
Power supply
24VDC, 120VDC - 370VDC, 85VAC - 265VAC/47 - 63Hz,USB-C female (5V DC via USB-C) for programming -
Power consumption
typ. 1.2W, max. 2W -
ESP32
ESP32-WROOM-32U -
1-WIRE
2-separate 1-WIRE bus, 5VDC bus power supply, ESD Protected -
USB
USBUSB type-C USB Specification 2.0 compliant, ESD protected, Silicon Labs CP2102N USB-to-UART bridge controller, Virtual COM Port Device Drivers, Works with existing COM port Applications, Supported on Windows, Mac, and Linux -
Ambient
Temperature 0 ... 50°C / 32 ... 122°F, Humidity max. 95% r.H. (non condensing)
-
Wi-Fi
Reliablity HTOL/HTSL/uHAST/TCT/ESD, Protocols 802.11 b/g/n (802.11n up to 150 Mbps), A-MPDU and A-MSDU aggregation and 0.4 µs guard interval support, Frequency range 2.4 GHz ~ 2.5 GHz -
Bluetooth
Protocols Bluetooth v4.2 BR/EDR and BLE specification, Radio NZIF receiver with –97 dBm sensitivity, Class-1, class-2 and class-3 transmitter, AFH -
Digital Output
1 digital output (relay with optocoupler and varistor surge protection), dry contact, 250VAC 16A at cosᵠ =1,250VAC 9A at cosᵠ =0.4, 30VDC 10A -
OpenTherm
7-15V DC with up to 35mA current
