Skip to content
Python OTGW MQTT bridge
Branch: master
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Type Name Latest commit message Commit time
Failed to load latest commit information.


Hi everyone, I've changed my set-up so I now use Node-RED for most of my home automation, including control of my OTGW. That means I don't really have any use for this package anymore. If someone would like maintain this package, please let me know. Otherwise, I'll still try to respond to issues, but I'm probably not going to add any features or fix bugs anytime soon.

You may want to look at one of the forks of this repo to find a maintained version. If you just want to connect your OTGW to Home Assistant, I suggest you look at the official component. It's possible to use this component over TCP with ser2net as per the example here.

Python OTGW MQTT bridge

This package allows for communication between an OpenTherm Gateway, running the firmware by Schelte Bron and an MQTT service. It was tested using Home Assistant's built-in MQTT broker.

Supported OTGW gateway communication protocols

Currently, only direct serial communication is supported, but implementing further types is pretty easy. I'm open to pull requests.

Supported MQTT brokers

The MQTT client used is paho. It's one of the most widely-used MQTT clients for Python, so it should work on most brokers. If you're having problems with a certain type, please open an issue or send me a pull request with a fix.


The configuration for the bridge is located in config.json.

Example configuration

    "otgw" : {
        "type": "serial",
        "device": "/dev/ttyUSB0",
        "baudrate": 9600
    "mqtt" : {
        "client_id": "otgw",
        "host": "",
        "port": 1883,
        "keepalive": 60,
        "bind_address": "",
        "username": null,
        "password": null,
        "qos": 0,
        "pub_topic_namespace": "value/otgw",
        "sub_topic_namespace": "set/otgw"


To install this script as a daemon, run the following commands (on a Debian-based distribution):

  1. Install dependencies:
    sudo apt install python python-serial
  2. Create a new folder, for example:
    sudo mkdir -p /usr/lib/py-otgw-mqtt
    cd /usr/lib/py-otgw-mqtt
  3. Clone this repository into the current directory:
    sudo git clone .
  4. Change config.json with your favorite text editor
  5. Copy the service file to the systemd directory. If you used a different folder name than /usr/lib/py-otgw-mqtt you will need to change the WorkingDirectory in the file first.
    sudo cp ./py-otgw-mqtt.service /etc/systemd/system/
  6. Enable the service so it starts up on boot:
    sudo systemctl daemon-reload
    sudo systemctl enable py-otgw-mqtt.service
  7. Start up the service
    sudo systemctl start py-otgw-mqtt.service
  8. View the log to see if everything works
    journalctl -u py-otgw-mqtt.service -f


Publish topics

By default, the service publishes messages to the following MQTT topics:

  • value/otgw => The status of the service
  • value/otgw/flame_status
  • value/otgw/flame_status_ch
  • value/otgw/flame_status_dhw
  • value/otgw/flame_status_bit
  • value/otgw/control_setpoint
  • value/otgw/remote_override_setpoint
  • value/otgw/max_relative_modulation_level
  • value/otgw/room_setpoint
  • value/otgw/relative_modulation_level
  • value/otgw/ch_water_pressure
  • value/otgw/room_temperature
  • value/otgw/boiler_water_temperature
  • value/otgw/dhw_temperature
  • value/otgw/outside_temperature
  • value/otgw/return_water_temperature
  • value/otgw/dhw_setpoint
  • value/otgw/max_ch_water_setpoint
  • value/otgw/burner_starts
  • value/otgw/ch_pump_starts
  • value/otgw/dhw_pump_starts
  • value/otgw/dhw_burner_starts
  • value/otgw/burner_operation_hours
  • value/otgw/ch_pump_operation_hours
  • value/otgw/dhw_pump_valve_operation_hours
  • value/otgw/dhw_burner_operation_hours

If you've changed the pub_topic_namespace value in the configuration, replace value/otgw with your configured value. TODO: Add description of all topics

Subscription topics

By default, the service listens to messages from the following MQTT topics:

  • set/otgw/room_setpoint/temporary
  • set/otgw/room_setpoint/constant
  • set/otgw/outside_temperature
  • set/otgw/hot_water/enable
  • set/otgw/hot_water/temperature
  • set/otgw/central_heating/enable

TODO: Add description of all topics

You can’t perform that action at this time.