How does HM-CC-RT-DN and HM-TC-IT-WM-W-EU work together

Dear community,

I’m new to home automation and was thinking to start the new project with a simple heating solution to optimize and controll our heating in a central way.

Therefore I bought a PI with a HM-MOD-RPI-PCB and the two homematic components HM-CC-RT-DN and HM-TC-IT-WM-W-EU. The PI is running Openhabian with Openhab2.2. All devices are are availbale and I can see the different channels in the Paper UI.

The goal is to NOT use the thermostat of the HM-CC-RT-DN but of the HM-TC-IT-WM-W-EU which is placed in a different corner oft he room than the HM-CC-RT-DN As soon as the HM-TC-IT-WM-W-EU target temperature is reached the HM-CC-RT-DN should close the valve (stop heating). If the HM-TC-IT-WM-W-EU target temperature drops below the actual temperature the HM-CC-RT-DN should open the valve and start heating again till the HM-TC-IT-WM-W-EU target temperature is reached.

I read a lot through serveral posts (especially the Heating Boilerplate by Thomas Dietrich) but it’s still not clear to me how the two items work together since both of them measure the temperature.

If using the HM-TC-IT-WM-W-EU to controll the HM-CC-RT-DN will the temperature sensor of the HM-CC-RT-DN be disabled or stop working - does that have to be configured somewhere?

Do I have to send the HM-TC-IT-WM-W-EU actual temperature in intervalls to the HM-CC-RT-DN to overwrite the HM-CC-RT-DN actual temperature to trick out the HM-CC-RT-DN temperature sensor?

Or do you open the the valve of the HM-CC-RT-DN till the HM-TC-IT-WM-W-EU target temperature has been reached.

Maybe somebody is has a similar setup and can share his OpenHab configuration for this scenario.

Kind regards


You should setup direct links between the devices. These device can and should be used independent of openhab. I have 10 wall and 15 radiator thermostats running and everything works without openhab. Openhab just adds another layer of comfort.

The “heating boilerplate” as far as I remember is a general system for all kind of (even the dumbest) heating devices. The Homematic devices are smarter than others.

How to setup the direct links depends on your connection method. I am using homegear and use php scripts to setup mine. I have too many for manual interaction.

Other methods are webui of ccu or Homematic konfigurator for windows (download from eq3).

I have similar setup and coupled the wall and radio thermostats directly (including the window contact). I am using openHAB to control the wall thermostats.

I have also created a base programming in Homematic itself.

There is another advantage of this solution: the programming is stored in the thermostats. This means they can work independently of openHAB or even a CCU / Homegear.

Hi Martin,

thanks for your response. By coupling do you mean to teach-in the HM-TC-IT-WM-W-EU to the HM-CC-RT-DN (as described in the manual HM-TC-IT-WM-W-EU-Setup-Guide on page 57 - chapter 9.1?

After both devices are coupled all the configuration, all possible rules and logic are configured for the HM-TC-IT-WM-W-EU. There is no logic or programming build around the HM-CC-RT-DN. The HM-CC-RT-DN is only “executing authority” in sense of opening the valve till the HM-TC-IT-WM-W-EU target temperature is reached - correct?

Kind regards

Hi Willil,

my first answer was not precise enough. You have to teach-in all devices to the CCU (chapter 17). Then on the CCU you create a “Group” (in the german CCU under Einstellungen / Gruppen). To the group you add the radiator thermostats and the wall thermostat. E.g. I have to a group for my living room that contains 3 radiator thermostat, one wall thermostat and a window contact.

The HM-CC-RT-DN is only “executing authority” in sense of opening the valve till the HM-TC-IT-WM-W-EU target temperature is reached - correct?

Exactly. By grouping the device they are coupled with each other and in addition they are connected to the CCU.

Hmm, but I don’t own any CCU. Only a Raspberry PI with HM-MOD-RPI-PCB modul and OpenHab 2.2. installed. How would I setup the groups you mentioned in your scenario with my kind of setup?

Auch Software are YouTube using tomorrow configure your Homematic devices? Homegear? I suppose that there is a Simulation option. I am using Rasperrymatic that ist based in the original software that ist running on the ccu.

You are most likely using homegear. You can download the configuration software from eq3 as I mentioned in my first answer.

You need to setup direct links between the devices. (Direktverknüpfung)

Hi Martin,

looks like I’m using the Homegear CCU emulation software. I’ve never configured any of the Homematic devices. I just paired them via commandline on my PI and started creating Things and Items. What is there to be configured?

Hi Joachim,

I just cheked and it looks like I’m indeed using the Homegear CCU emulation software. I missed your hint concerning the eq3 software. I’ll download it later today. But why do I have to use that software to connect the HM-TC-IT-WM-W-EU with the HM-CC-RT-DN? Isn’t it also possible to simply teach-in the HM-TC-IT-WM-W-EU with the HM-CC-RT-DN as described HM-TC-IT-WM-W-EU-Setup-Guide on page 57 - chapter 9.1? Is there any disadvantage doing this or won’t it work generally that way?

Kind regards

Hello Willi,

whats described on page 57 is the “light” mode to connect two HM devices if you don’t own a CCU. As far as I know once HM devices are connected to a CCU (Homegear in your case) the “light” way of connecting them will not work any longer (so you will not get them connected to OH anymore).

You will either need to use the configurator software from eq3 (I’ve had no luck with it) mentioned above that connects to Homegear on the PI or install a full CCU3 image on your PI. RaspberryMatic is the easiest way but does not allow to run OpenHab on the same PI but there are other distributions (piVCCU?) which can be installed side by side with OH. With a full CCU3 installation you will be able to use its web interface to do the coupling.

Homegear also allows you to run PHP scripts to control every aspect of the connected devices. It should be possible to create the connection in this way too, but this will require deep knowledge of the protocol.

So my conclusion: try to install RaspberryMatic on a separate Pi (which has the HM-MOD-RPI-PCB module attached) and use this as the CCU instead of Homegear. This is the easiest solution for a beginner I think.

PS: don’t forget to unpair/disconnect your devices from Homegear before going this step. This is important because they will refuse any connections if they are still paired and there is no way to reset the pairing at the device (for security reasons).

@thorsten_gilfert @job and also MHerbst (as a new users I’ can only mention two users :frowning: )

thanks for your input. Combining all your answers I get the picture. Since I don’t want to install extra software or setup a second PI I dug in a little bitt deeper: With homegear it should be possible to link two devices via command line using a simple command like homegear -e ‘rc $hg->addLink(22,1,8,3);’

The device id’s should be get by rc print_r($hg->listDevices())

Can you tell me if addLink is the right command and which cannels you need to link between a HM-CC-RT-DN and a HM-TC-IT-WM-W-EU?

Yes, addLink is the correct function. The link between wall and radiator thermostats is done via channel 2 on both sides.


The result of that command is exactly the same as if you had paired the devices directly to each other. (Or Direktverknüpfung with the Homematic Konfigurator.).

Homegear is also getting an AdminUI which will enable you to setup the links via the web-browser in the future. But this is currently alpha stage and device configuration is just partial implemented. But you may already setup your heating profiles:


A good source of information is also the homegear forum


I’d like to revive this topic with my current issue.

I’ll try to simplify my set-up as follows (it’s just part of my set-up):

  • Homematic CCU2
  • Homematic Wall Thermostat (HM-TC-IT-WM-W-EU)
  • Homematic 3 x radiator thermostats (HM-CC-RT-DN)
    All those are virtually grouped together - HM-CC-VG-1- in the CCU2 and working great for years.

Now I’ve integrated all those into OH 2.5.
First issues:

  • working with the Wall Thermostat (HM-TC-IT-WM-W-EU) did work on the Thermostat but did not send the actions to the radiator thermostats (HM-CC-RT-DN)
  • working with one of the radiator thermostats (HM-CC-RT-DN) had the same effect

So I’now configured everything though "the"virtual device group including all 4 elements: HM-CC-VG-1.

String SalleMangerCuisine_1_ControlMode “Mode CCU2 [%s]” { channel=“homematic:HM-CC-VG-1:LEQ1005832:INT0000003:1**#CONTROL_MODE**” }
Switch SalleMangerCuisine_1_AutoMode “Automatic mode” { channel=“homematic:HM-CC-VG-1:LEQ1005832:INT0000003:1#AUTO_MODE” }
Number SalleMangerCuisine_1_SetTemperature “Target temperature [%.1f °C]” { channel=“homematic:HM-CC-VG-1:LEQ1005832:INT0000003:1#SET_TEMPERATURE” }
Number SalleMangerCuisine_1_ManuMode “Manual mode” { channel=“homematic:HM-CC-VG-1:LEQ1005832:INT0000003:1#MANU_MODE” }
Number SalleMangerCuisine_1_ActualTemperature “Current temperature [%.1f °C]” { channel=“homematic:HM-CC-VG-1:LEQ1005832:INT0000003:1#ACTUAL_TEMPERATURE” }
String SalleMangerCuisine_1_Control_Mode_openHAB “Mode openHAB[%s]”

Rules: I have 2 rules
//ThermostatSalle a Manger Cuisine via groupe
rule “ThermostatSalleaManger mode via Grouoe 3 Vannes”
Item SalleMangerCuisine_1_Control_Mode_openHAB changed
logDebug(“homematic”, “Mode switcher rule of group Salle à Manger/Cuisine executed with control mode ‘{}’”,

if(“MANU-MODE”.equals(SalleMangerCuisine_1_Control_Mode_openHAB.state.toString)) {
SalleMangerCuisine_1_ManuMode.sendCommand(SalleMangerCuisine_1_SetTemperature.state as Number)
logInfo(“homematic”, “Switched group Salle à Manger/Cuisine to MANU_MODE with value {}”,
SalleMangerCuisine_1_SetTemperature.state as Number)
} else if(“AUTO-MODE”.equals(SalleMangerCuisine_1_Control_Mode_openHAB.state.toString)) {
logInfo(“homematic”, “Switched group Salle à Manger/Cuisine to AUTO_MODE”)
} else if(“BOOST-MODE”.equals(SalleMangerCuisine_1_Control_Mode_openHAB.state.toString)) {
logInfo(“homematic”, “Switched group Salle à Manger/Cuisine to BOOST_MODE”)

rule “Sync thermostat mode ThermostatSalleaManger via groupe”
Item SalleMangerCuisine_1_ControlMode changed
logDebug(“homematic”, “New control mode sent by CCU2 to group Salle à Manger/Cuisine is ‘{}’”,

And the sitemap
Frame label= “Salle à Manger/Cuisine (Groupe)”{
Text item=SalleMangerCuisine_1_ActualTemperature icon=“thermo”
Frame label= “Salle à Manger/Cuisine (Groupe)” {
Text item=SalleMangerCuisine_1_ActualTemperature icon=“thermo”
Slider item=SalleMangerCuisine_1_SetTemperature switchSupport minValue=4.5 maxValue=24 step=0.5 icon=“vanne”
Setpoint item=SalleMangerCuisine_1_SetTemperature step=0.5 minValue=4.5 maxValue=24
Text item=VanneCuisine_4_SetTemperature icon=“thermo”
Switch item=SalleMangerCuisine_1_Control_Mode_openHAB mappings=[“AUTO-MODE”=“Automatic”, “MANU-MODE”=“Manual”, “BOOST-MODE”=“Boost”]
Text item=SalleMangerCuisine_1_BoostState icon=“Fire”


The “slider” works ok but is not very accurate so I’ve added a “Setpoint” for fine t° definition.
All this works fine.
BUT the values that are sent back are not updated !
If I manually change the t° or mode on the thermostat or on the radiators…it is not reflected in OH.

On the contrary my set-up works like a charm on all my stand-alone (not linked to a wall thermostat) other radiator thermostats !
All values are updated dynamically without issue.

Would you see where my error is ???
Thanks a lot for your review

Anyone awake ? :slight_smile:

You will get a much better response creating a new topic dedicated to your issue and linking to one you think is related. You also have to use code fences to make your code readable… right now, it is a blob if unformatted text.

Ok, will do.

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