EMS bus compatibility

EMS bus versions

The EMS bus has been around for quite a number of years. It has evolved into several versions:

  • EMS
  • Logamatic EMS
  • EMS2
  • EMS+
  • EMS Plus
  • Heatronic
  • Heatronic 3
  • 2 wire bus

They all use the same physical bus, but the protocol used on the bus may vary slightly between versions.

Other bus protocols

Old boilers do not support the EMS protocol but may use the iRT protocol. Also a small number of Bosch boilers use OpenTherm instead of EMS.

Bosch boiler brands

Bosch boilers brands include:

  • Bosch
  • Buderus
  • Nefit
  • Junkers
  • Worcester
  • Sieger

EMS device support list

Support for specific devices depends on the firmware on the Gateway. Support for new devices is added with every new release. If your device is not in the list below, it might still be fully or partially compatible. If you are missing parameters you can open an issue on the code repository to get support. The list below summarizes EMS bus devices that are supported in firmware version 1.9.4 (December 2019).

The firmware supports all 4 heating circuits 1 to 4 simultaneously.


  • Buderus GBx72, GB162, GB152, GB125, Logamax U122, Logamax Plus GB192, Logamax Plus GB122, Logano
  • Bosch Condens 2500
  • Worcester-Bosch Greenstar 550CDi
  • Worcester Bosch Greenstar 24i
  • Junkers Cerapur, Junkers Heatronic 3 boilers
  • Nefit Proline, Trendline, Topline, Enviline, Smartline
  • Sieger BK13 and BK15 Boiler

Heat pumps

  • Buderus HeatPump Module
  • Nefit Enviline


  • Buderus RC10, RC20, RC20F, RC30, R35, RC300, RC310, RC3000
  • Buderus Logamatic TC100 (read-only)
  • Nefit Moduline 100, 300, 400
  • Nefit Moduline 1010, 3000 (read-only)
  • Nefit Moduline Easy (read-only)
  • Bosch CW100, Easy Control/CT200 (read-only)
  • Junkers FR10, FR50, FR100, FR110, FW100, FW120
  • Sieger ES73

Solar Modules

  • Buderus SM10, SM50, SM100 Solar Module
  • Junkers ISM1 Solar Module

Mixing Modules

  • Buderus MM10, MM50, MM100, MM200 Mixer Module

Other devices

  • Generic Buderus MC10 Module
  • Buderus WM10 Switch Module
  • Buderus RFM20 Receiver
  • Buderus BC10, BC25, BC40 Base Controller
  • Buderus Web Gateway KM200
  • Nefit Moduline Easy Connect
  • Bosch Easy Connect
  • EMS-OT OpenTherm converter
  • Junkers Controller

Non supported devices

Older boilers that use the iRT protocol like the Nefit Ecomline.

  • Nefit Ecomline
  • Boilers with an UBA 1.0 / UBA 4000
  • Boilers with an UBA 1.5 / UBA 4001

Boilers that use the OpenTherm protocol

  • Nefit ProLine NxT (however the ‘normal’ ProLine uses EMS).

Getting support

If your EMS boiler or device is not in the list or it is but you are missing parameters, open an issue on Proddy’s Github repository [1] to get support.

Home automation system compatibility

  • Home Assistant
  • Domoticz
  • Other MQTT capable systems