• PIC Microcontroller
  • No tools required to insert wires
  • Parts in kit
  • Kit as shipped
  • with optional Ethernet
  • with optional WeMos (Wifi)

OpenTherm Gateway Kit

Tax included

OTGW (OpenTherm GateWay) is based on an open source project by Schelte Bron.

You will find more information at: http://otgw.tclcode.com 

Built to order

OTGW (OpenTherm GateWay) is based on an open source project by Schelte Bron. You will find more information on this website: http://otgw.tclcode.com 

Please note that this product can be expanded with a maximum of one optional board for WiFi,  Ethernet, or Serial.

The OTGW is sold as a kit. The SMD components are already fitted, only three components need to be added. If you don't want to build the kit, order the soldering service. The OTGW will then be delivered ready to use. You may also wish to order an enclosure.

The board obtains its power via USB. You may be able to use a power supply you already own, or you can purchase a power supply. A high quality USB cable is recommended.

Another source for information is the Domotica OTGW forum: OTGW Forum

On OTGW boiler and thermostat matrix you will find a list of boilers and thermostats compatible with the kit, and also which functions are supported.

During normal operation, the OTGW will communicate with the boiler and the thermostat via the two-wire OpenTherm link: the OTGW must be installed between boiler and thermostat. For programming, the OTGW can be linked to your computer using a USB cable. It is also possible to connect via Wifi, Ethernet or RS-232 serial using optional boards available for purchase separately. On delivery, the OTGW kit includes a pre-programmed PIC with the latest firmware. Tools and future firmware can be downloaded from OTGW download (http://otgw.tclcode.com/download.html). 

Supported features:

  • Monitor and log Opentherm communication between boiler and thermostat
  • Change thermostat temperature setpoint
  • Add outside temperature to thermostat display (if supported by thermostat)
  • Read outside temperature sensor
  • Control hot water supply (if supported by boiler)
  • Supports the following situations:
    • Opentherm thermostat
    • On/off switching thermostat
    • No thermostat present

Note that for several of these functions you will need a controlling program, for instance Domoticz.

Now supplied with PIC16LF1847 ready programmed with version 6 firmware

Specific References



Driver for CH340 Serial

Download (179.66KB)

OpenTherm Gateway Manual

Download (1.32MB)

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