EMS device compatibility

Electrical compatibility

The EMS interface boards and the Gateways are electrically compatible with all EMS and Heatronic varieties. These include EMS, EMS+, EMS2, EMS Plus, Logamatic EMS, Junkers 2-wire, Heatronic, Heatronic 3. The EMS bus is 16V.

Do not connect any EMS product to an OpenTherm bus, or a 24V or mains power thermostat bus!

EMS devices

The support for EMS devices depends on the firmware of the Gateway.

Most Bosch branded boilers that support the Logamatic EMS / Heatronic bus protocols work with this design. This includes Nefit, Buderus, Worcester, Junkers and Sieger.

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).


  • 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


  • 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

Solar Modules:

  • Buderus SM10, SM50, SM100, SM200 Solar Module
  • Junkers ISM1 Solar Module

Mixing Modules:

  • Buderus MM10, MM50, MM100, MM200 Mixer Module

Heat Pump Modules:

  • Buderus HeatPump Module
  • Nefit EnviLine

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

Devices that are NOT compatible

  • Older boilers like the Nefit Ecomline that use the iRT protocol.
  • Several Junkers boilers that use a CAN BUS (they might be ‘Heatronic’, but that’s the name of the boiler controller).