EMS device compatibility

Electrical compatibility

The EMS interface boards and the Gateways are electrically compatible with all EMS and Heatronic 3 and 4 versions. These include EMS, EMS+, EMS2, EMS Plus, Logamatic EMS, Junkers 2-wire, Heatronic 3, 4. 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.

Each Gateway is preloaded with a stable version of EMS-ESP.

Most Bosch branded boilers that support the Logamatic EMS / Heatronic bus protocols work with this firmware. This includes Bosch, 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 3 (October 2021).


The table below provides a list of thermostats and which features are supported.
For some thermostats you cannot change the setpoint via the EMS bus. These have a ‘No’ in the ‘Write’ column.
So for these thermostats you can read the parameters, but they don’t respond to write requests.
Additionally, some of the WiFi connected thermostats don’t send any heating data over the bus, they are ‘detected-only’.

If a thermostat supports multiple heating zones, this will be supported by the Gateway as well.

The table below is for reference only, support depends on the EMS-ESP firmware version.

Buderus RC10
Nefit Moduline 100
Buderus RC20
Buderus RC20RF
Nefit Moduline 200
Buderus RC25YesYesYes
Buderus RC30
Nefit Moduline 300
YesYesYesThe Moduline 300 supports EMS but also iRT, so make sure you have an EMS boiler.
Buderus RC35
Nefit Moduline 400
YesYesYesThe Moduline 400 supports EMS but also iRT, so make sure you have an EMS boiler.
Buderus Logamatic TC100
Bosch Easy
Nefit Easy
Bosch Easycontrol
YesNoNoThis thermostat does not send any heating data over the EMS bus. The Gateway can see its presence, but that’s it. You can’t read or write the temperature via EMS.
The problem is a shortcoming of this specific model of thermostat and not of the Gateway. Therefore in its current state it can never be supported by any future firmware update of the Gateway (But you can see the boiler parameters with the Gateway of course).
Buderus RC100
Nefit Moduline 1000
Nefit Moduline 1010(H)
YesYesYesThe Moduline 1000/1010 supports both EMS and OpenTherm. Make sure your boiler is EMS!
Junkers CR10(H)This one is likely the same as the Buderus RC100.
Bosch CW100YesYesYes
Buderus RC200YesYesNo
Buderus RC300
Buderus RC310
Nefit Moduline 3000YesYesNo
Bosch CW400YesYesYes
Junkers FR10YesYesYes
Junkers FR10
Junkers FR100
Junkers FW100
Junkers FW120
Junkers FW200
YesYesYes** FW200 etc only writable for production date August 2008 (code FD 889) or later. See the table here on how to convert the code on the thermostat to the production date.
Junkers FR50
Junkers FR110
Junkers FR120
Sieger ES72YesYesYes
Sieger ES73YesYesYes
Tado thermostatTadoYesYesNoThe Tado thermostat emulates a Buderus RC10, but not perfectly.
You cannot write the setpoint via the EMS bus. So only read for this one.


All EMS boilers send out the status of about 30 to 40 of its parameters to the bus every 10 to 60 seconds.

The table below gives an overview of boilers that have been tested with EMS-ESP. Lot’s of boilers have a service jack, but a lot of them don’t have it. In the latter case the Gateway connects to the thermostat wires or the EMS bus coonector inside the boiler. Also see the wiki.

There are more boilers not in the list that are supported.
In general all EMS, EMS+, Heatronic 3 and Heatronic 4 boilers are supported however for some the boiler ID still has to be included in the list.

To make it easier to identify a supported boiler check if it has one of the following control panels. If so, it is likely compatible.
Some of the control panels might also include a thermostat as well, and the color might be white, black or grey.
I have not listed all possible boilers yet, so if the control panel on your boiler looks different, send me email so I can check whether it is supported.

BrandModel/RangeControllerService jackRemarks
NefitTrendLine (II)Yes
NefitProLineYesThe ProLine NXT and ProLine ECO are OpenTherm and not EMS. The normal ProLine is EMS though.
NefitEcomline EliteYesThe Elite is the only boiler from the Ecomline range with a EMS-bus UBA3. All other Ecomlines use iRT and are NOT supported.
This boiler might have a Moduline 30 thermostat connect via a RCC module. In this case the thermostat won’t be detected. Just buy a Moduline 400 from f.i. Marktplaats in that case.
BoschCondens 2500
Condens 2500W
Condens 2500 WBC
NoThis boiler has one single connector for both EMS and on/off thermostats.
If you have an on/off thermostat you cannot use the Gateway (Or only in RX mode). Use an EMS thermostat instead.
BoschCondens 2300i
Condens 5000i
Condens 5300i
BoschCondens 7000i(W)Yes
BoschCondens 9000i
Condens GC9000
BuderusLogamax GB172yes
Buderus GB192i
BuderusLogamax Plus GB022 Yes
BuderusBoiler with MC110 controllerYesThis EMS+ controller sends out new types of telegrams which have been mostly decoded. See https://emsesp.github.io/docs/#/MC110-controller
WorcesterGreenstar 440CDi
Greenstar 550CDi
Combi Greenstar Highflow CDi
WorcesterSystem Greenstar CDi Classic SystemNoOnly boilers manufactured after 16th January 2007 with software version CF12.10 onwards.
WorcesterSystem Greenstar 9i
System Greenstar 12i
System Greenstar 15i
System Greenstar 18i
System Greenstar 21i
System Greenstar 24i
NoOnly boilers manufactured after 2011 and with an integral diverter valve – provided optional integral diverter
valve is installed.
WorcesterCombi Greenstar i JuniorNoManufactured after July 2013
WorcesterCombi Greenstar iNo
WorcesterSystem Greenstar 27i
System Greenstar 30i
Combi Greenstar Si Compact
Combi Greenstar CDi Compact
YesNot in the list yet
JunkersCerapur CompactNoThis boiler has one single connector for both EMS and on/off thermostats.
If you have an on/off thermostat you cannot use the Gateway. Use an EMS thermostat instead.
JunkersCerapur Smart
Cerapur Comfort
Cerapur ACU
Cerapur Modul
JunkersCerapur 4Yes
Cerapur MaxxYes
JunkersAll with Heatronic 3 controller (ZSB, ZWB, ZWBC)No
JunkersAll with Heatronic 4 controllerNo
elm.leblancCONDENS and other gas condensing (Chaudières condensation) models with EMS bus.See Junkers models above. If it has the same control panel, it’s compatible.No

There is a large number of boiler parameters that can be read out, usualy more than 50. A certain amount of parameters can also be set by the Gateway. Which parameters you can set really depends on the exact brand, type, year and software version of your boiler. For some boilers you can set a particular parameter, but the boiler will override it again after a few seconds. F.i. boilers that have manual knobs on the front for the max/flow temperature, may not always allow this parameter to be set by the Gateway.

Heat Pump Modules:

All EMS heat pumps send out the status of about 30 to 40 of its parameters to the bus every 10 to 60 seconds.
The table below gives an overview of heat pumps that have been tested with EMS-ESP. For the heat pumps a lot of parameters are available, but not all yet. Full support for the heat pumps is still under development.
Most or all heat pumps have a service jack that is on a cable inside the housing. Also see the wiki.

and other EMS based heat pumps
NefitEnviLineThe very first Enviline did not use the EMS bus. All other should be fine.
JunkersCerapur Aero
IVTModels with EMS bus
elm.leblancCondens HybrideLikely compatible, but NOT yet confirmed to work

You get at least parameters like pump modulation, flow, setpoint/actual and return temperatures, all total energy values for delivered heating, cooling, and for which mode (warm water, heating) and the total energy consumption for each mode.

Solar Modules:

BuderusSM200yesyesUses new EMS+ telegrams.

Mixing Modules:

BoschMP100YesYesPool mixer

Other devices:

The devices below are detected by the Gateway but most of them do not have any meaningful interaction with the bus (They have no parameters you can see or control).

BuderusMC10YesType of controller.
BuderusWM10YesLow loss header mixer module.
BuderusRFM20YesReceiver module.
BC10, BC22, BC25, BC40YesBase controller. This is the display unit on the boiler with the buttons.
Web KM50
YesThis is the Bosch web Gateway. If your boiler/heatpump has an Ethernet port, one of these modules is built in and will be reported as such by the Gateway.
NefitModuline Easy ConnectYesAdapter.
BoschEasy ConnectYesAdapter.
EMS-OTEMS-OT OpenTherm converterYesEMS-OT converter.
JunkersHT3 controllerYesController.

Devices that are NOT compatible

Some Bosch brands devices that are not compatible are listed below.

Non-compatible boilers

Very old Bosch brands boilers (<2007) might not be EMS based but iRT or another protocol.
Below a small selection of boilers that are known to be incompatible.

BuderusU104, U112, U114, U122, U124, GB112, Linea Kombi 23.iRT
NefitEcomline Classic
Ecomline Excellent
Ecomline Economy
UBA 1.0 / UBA 1.5 / UBA 4000 / UBA 4001iRTThermostat is often the Moduline 30.
For the Ecomline there is now experimental support with a slightly modified EMS interface board.
NefitProLine NxT
ProLine Eco
OpenThermThe non-NxT ProLine is EMS!
24V on/off
JunkersSome older Junkers boilers use a CAN bus for the thermostat.With BM1 or BM2 CAN bus module.CAN busMight have a TR220 thermostat.
JunkersAll models with Heatronic or Heatronic 2.
F.i. Eurostar ZWE, ZSE, ZSBR.
3-wire bus with Junkers (PWM) 24V The thermostat is usually a TR21, TR100 or TR200.
BuderusLogamatic 2105, 2107 etcECO-CANController mainly used for oil boilers
Bosch4500FMOpenThermThe optional thermostat connector inside is a Siemens OpenTherm plug.

Non-compatible thermostats

Below some thermostats that are not compatible. If you have such a thermostat, the boiler won’t be compatible as well.

Nefit Moduline IViRT
Nefit Moduline 10iRT
Nefit Moduline 20iRT
Nefit Moduline 30iRTThis thermostat was used often together with a Nefit Ecomline boiler. However, early EMS boilers sometimes also use this thermostat via so called RCC module.
Nefit RCC ModuleEMSThis module allows you to connect an iRT thermostat of the above to an EMS boiler.
If your boiler is EMS, but has a RCC module and an old iRT Moduline thermostat, remove the RCC module and the old thermostat and buy f.i. a second hand Moduline 400 from Marktplaats. They are only about 25 Euro second hand. This way you have all features and you can set the temperature via the Gateway.
Junkers TR213-wire Junkers (PWM) 24V
Junkers TR2003-wire Junkers (PWM) 24V
Sieger eRS62I2C?
Bosch TRZ200

Other non-compatible devices

All Buderus Logivent and Junkers Aerastar ventilation systems (No EMS bus).