EMS-bus-Gateway

Almost all Bosch brand boilers from the last 20 years or so use the same EMS bus interface to connect thermostats, solar/mixer modules etc to the boiler/heat pump. Depending on the brand and the protocol version, the bus is called EMS, EMS+, EMS2, ‘2-wire bus’ and Heatronic 3.

EMS Bus Wi-Fi Gateway

The EMS Bus Gateway is a small device that provides a link between the EMS bus and a home automation like Domoticz. Just plug in the device to the service jack on the boiler with the supplied jack cable and stick it to the side of the boiler (its magnetic). Or connect it directly to the thermostat wires. No additional cables are needed and everything is powered from the service jack or the thermostat wires itself. All Gateways connect via Wi-Fi to your home network.

The Gateway runs the EMS-ESP firmware that communicates via MQTT. When connected to an EMS boiler or heatpump and to a thermostat, solar module, mixer module you can read out many parameters like flow and return temperature and change for instance the setpoint of the thermostat.

For Domoticz there is a Python plugin.

System compatibility

To check whether you EMS devices are supported see: *https://bbqkees-electronics.nl/ems-device-compatibility/. If its not in the list it may very well already be compatible and if not we can always add it to the ever growing database.

Plugin installation

The plugin and its installation instructions can be found here: *https://github.com/bbqkees/ems-esp-domoticz-plugin

DECEMBER 2021 -> YOU DO NOT NEED THIS PLUGIN ANYMORE

Domoticz now natively supports the Home Assistant MQTT Discovery protocol. The Gateway already supported this protocol. With a recent Domoticz version (late December 2021 and onwards) you can get all your EMS parameters into Domoticz without any further plugin. See HERE for the instructions on how to add it to Domoticz. With EMS-ESP until v3.3 all parameters except thermostats are read only, in EMS-ESP v3.4 this will be changed so that all settable parameters are added automatically.

Detailed information

There is a wiki with very detailed information on the bus and the Gateway: *https://bbqkees-electronics.nl/wiki

Getting a Gateway

To purchase a Gateway check the website: *https://bbqkees-electronics.nl/