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3. Supported Heating Systems and Controllers

In general BSB-LAN works with controllers built by SIEMENS which are supported with a BSB and/or a LPB. These controllers are branded and used by different manufacturers of heating systems (e.g. Broetje, Elco). Please read the manual of your heating system to find out if the controller offers a BSB and/or LPB.

Whenever I’m talking about the “controller”, I mean the so called “BMU” (boiler management unit). That’s the device with all the electronics inside, which controls the whole function of the heating system and which is located inside the housing of the heating system. At this device the sensors, pumps and the operating and room units are connected to.
The ‘operating unit’ and the optional room units are the devices located outside at the housing of the heating system, the ones with a display and some buttons to interact with the BMU/controller.

Some recent models of Broetje don’t have a BSB and are NOT compatible with BSB-LAN. Please see chapter 3.3 for further informations.

3.1 Successfully Tested Heating Systems

The following chapters are giving an overview of heating systems which have been successfully tested with BSB-LAN and reported by the users.
Because not every user reports his heating system, it can be assumed that in practise even more systems work successfully with the BSB-LPB-LAN adapter and the BSB-LAN software.

3.1.1 Broetje

The new models WLS/WLC and BOK by Broetje are NOT compatible with BSB-LAN!

3.1.2 Elco

3.1.3 Other Manufacturers

3.2 Detailed Listing and Description of the Supported Controllers

The following list of controllers and descriptions should give a short overview of a selection of devices already supported by BSB-LAN and their rudimentary differences. The different controller-specific availability of special parameters will not further received. It should be noted, however, that via BSB-LAN several parameters are available which aren’t available by the regular operating unit of the heating system itself.

3.2.1 LMx Controllers

The following subchapters are about the LMU and LMS controller types. These seem to be used within gas fired heating systems. LMU Controllers

Controllers of the series LMU54/LMU64 are installed in older systems, they are out of date. According to experience, these controllers have neither a BSB nor a LPB, only a PPS interface is available here. Sometimes LPB can be retrofitted by means of a ClipIn module (OCI420).

A LMU64 controller with an installed OCI420 ClipIn module.

Using BSB-LAN with these controller models is, according to experience, only possible to a limited extent. More detailed information can be found in chapter 3.4.

Controllers of the series LMU74/LMU75 appear to be the successors of the LMU54/LMU64 controller series and are also no longer installed. They have a BSB to which the adapter is connected and by means of BSB-LAN subsequently almost the complete range of functions is available. Only isolated (special) functions do not seem to be available (e.g. transmitting an alternative outside temperature via BSB-LAN).

A LMU7x controller.

The LMU7x controller type usually just offers BSB connection. If needed, LPB needs to be retrofitted using a ClipIn module (OCI420) (this is not necessary for using BSB-LAN though!). The control unit usually is a variant of the Siemens AVS37.294 (so called “ISR Plus” whithin Broetje). LMS Controllers

Controllers of the series LMS seem to be the successors of the LMU series and thus the current controller generation. With this controller type, experience has shown that the complete range of functions can be used with BSB-LAN.

The (functional) difference between the LMS14 and the LMS15 seems to be the “Sitherm Pro” application to optimize the overall combustion process, which apparently only the LMS15 controller seems to offer.

The LMS controller type usually just offers a BSB connection. If needed, LPB needs to be retrofitted using a ClipIn module (OCI420) (this is not necessary for using BSB-LAN though!).

A LMS15 controller.

The operating unit usually is a variant of the Siemens AVS37.294 (so called “ISR Plus” whithin Broetje).

3.2.2 RVx Controllers

The following subchapters are about the RVA, RVP and RVS (current one) controller types. These seem to be used within oil fired heating systems, heat pumps and different ‘standalone’ systems (like solar or zone controllers). RVA and RVP Controllers

Controllers of the type RVA seem to belong to the previous controller generation and, depending on the model, only offer a PPS or a PPS and a LPB connection (no BSB).
As an (included) operating unit usually a variant of the so called “Eurocontrol” (Broetje) is installed.
Operation via BSB-LAN is only possible to a much lesser extent than with the current controller generation RVS.

A RVA53 controller.

Frontside view: Operating unit of a RVA53 controller.

Controllers of the type RVP seem to be even older than RVA controllers and only offer a PPS interface.
The scope of operation within this controller type via BSB-LAN only is possible in a very limited extent. RVS Controllers

Controllers of the type RVS seem to be the current controller generation and will usually be fully supported by BSB-LAN.
They usually offer both a LPB and several BSB connections.
Exceptions seem to be the controllers of the series RVS21, RVS41, RVS51, RVS61 and RVS23:

The operating unit usually is a variant of the Siemens AVS37.294 (so called “ISR Plus” whithin Broetje).

The following gives a short overview of the main RVS controller types.
The RVS21 is the type of controller which is used in heatpumps. It offers BSB and a pair of connectors for an optional room unit.

A RVS21 controller.
The RVS41 is another type of controller which is used within heat pumps. it offers BSB and LPB and seems to be pretty identical to the RVS43 (at least judging by the look of it).
The RVS43 is the type that usually is built in oil fired burner systems. The number of connectors and functions could be expanded with an AVS75 expansion module.

A RVS43 controller.
The RVS46 is a small zone controller, which offers one (ZR1) or two (ZR2) connections for a pump/heating circuit. The RVS46 can control zones/circuits by it’s own, or integrated in the system via LPB connection to a main controller. It offers BSB and LPB.

The ‘small’ zone controller ZR1.

The ZR1/2 is not designed for controlling the whole functionality of e.g. a complete oil fired burner.
The RVS51 is the ‘bigger’ type of controller which is used in heatpumps. It offers BSB and LPB and seems to be pretty identical to the RVS63 (at least judging by the look of it).

A RVS51.843 controller.
The RVS61 is the ‘bigger’ type of controller which is used in heatpumps. It offers BSB and LPB and seems to be pretty identical to the RVS63 (at least judging by the look of it).
The RVS63 seems to be the ‘biggest’ controller with the most connectors and functions. Basically he is designed to control systems which are more complex, e.g. additionally solar thermic systems or an integrated oven. Therefore it is named “Solar System Controller” within Broetje.
The RVS63 can already be built in within complex heating systems or it could optionally added. In that case it comes with an external housing and must be connected via LPB to the already existing controller. In that case, all the sensors, pumps etc. of the main system have to be connected to the RVS63, because it becomes the ‘main’ controller for the whole system.

A RVS63 controller.

The seems to be pretty identical to the RVS63 and -until now- was reported only once by a user as being a wall-mounted “Solar System Controller” from Broetje.

3.2.3 Expansion- and ClipIn-Modules

If the available connectors and the range of function of the specific controller aren’t enough (e.g. retrofitting of a solarthermic system), one can expand the system by using an expansion- or ClipIn-module. An expansion module offers connectors for (e.g.) a pump circuit and the belonging sensors.
These modules are being connected at the main controller by using a special bus cable and the dedicated connector. Internally they are communicating with the controller via BSB (an exception seems to be the used controller type within the named Weishaupt heating systems). The parameterization takes places via the operating unit of the connected controller.
Therefore, access to an extension module is only possible via the specific parameters within the main controller. Because the expansion modules are listed within a query of ip/Q, I’ll present the two main types really short in the follwing.

If you want to retrofit an expansion module, of course see the specific manual of your heating system for further informations and call a heating engineer for the installation.

Expansion modules of the type are used within the RVS controller types. The bus connection usually takes places via the connector “Bus-EM”.

Expansion module AVS75.390.

Expansion modules for LMx controller types are named “ClipIn-module”. There seem to be different types for the specific needs (e.g. relay module, solar module). In general, the main appelation seems to be AGU2.5x (where the “x” seems to label the respective version), the bus connection usually takes place via the connector “X50”.

ClipIn-module AGU2.55.

3.2.4 Operating Units

The operating unit (located at the heating system itself) within the systems of the recent years (with controller types LMU7x, LMS1x, RVS) usually are types of the They look pretty much the same within the different manufacturers, within specific systems (e.g. heat pumps) certain buttons or functions can differ though.
If you compare the look of the AVS37 operating unit and the QAA75.61x room unit, you can see that they actually also look pretty identical and the usage of both devices is also almost the same. In most cases the heater sided operating unit constantly shows the temperature of the heating device and the room unit shows the room temperature. Both units spread these values regularly (approx. every 10 seconds) over the BSB as a broadcast (INF-message).

A typical operating unit AVS37.

Recently some manufacturers are using a new type of operating unit though, it’s called QAA75.91x. It seems to be possible to detach these units from the heater itself and -by using an optional connection setup- to install them in your living area. In that case they are still working as the main operating unit for the controller, but with the additional benefits of a room unit.

A QAA75.91x operating unit.

3.3 New Type: NOT Supported Controller from Broetje

It should be noted that the heating manufacturers introduced new device models to the market. According to current knowledge this type of controller is NOT compatible with BSB-LAN.

Within Broetje these seem to be the heating system series

These systems seem to have ‘IWR CAN’-based controllers built in (at the heater unit “IWR Alpha”, room unit “IWR IDA”), which have neither a LPB nor a BSB.

The following image of a WLC24 board shows the existing connections.

Connectors of the new controller model at a Broetje WLC24 - this controller is incompatible with BSB-LAN!

In addition to a service socket (probably IWR CAN) there are not further documented ‘L-Bus’ and ‘R-Bus’.
At the ‘R-bus’ (room unit bus) either a room thermostat (on / off) or the new ‘smart’ room unit “Broetje IDA” can be connected.

At none of these connectors the BSB-LPB-LAN adapter can be connected!

3.4 Special Case: LMU54/LMU64 Controller

LMU54 / LMU64 controllers are based on OpenTherm, which has different bus specifications and also a different communication protocol. Therefore, OpenTherm is not compatible with BSB-LAN.
However, often there is a possibility to connect this controller type anyway: as with the BSB controllers LMU7x and LMS1x, it is possible to retrofit a LPB by means of a so-called ClipIn module (OCI420). At this turn, the adapter can be connected.

A LMU64 controller with an installed OCI420 ClipIn module.

However, the functionality of this type of controller (even when using BSB-LAN) is relatively limited and also dependent to a certain extent on the software version of the controller (tested with LMU64, SW v2.08 vs. SW v3.0): controllers with SW from v3.0 seem to offer more functions (controllable via BSB-LAN) than controllers with SW <v3.0. In particular, the two setpoint temperature parameters 709 and 711 should be mentioned here. On their basis the burner behavior could be determined to a certain extent - these can only be used or changed with SW from v3.0. (Note: There is still an attempt if the burner behavior can be satisfactorily influenced by relays on another contact, but up to now we didn’t find a solution for that.)

However, according to current knowledge, parameters such as outside temperature, boiler temperature, DHW temperature, flow temperature, etc. can be accessed within both software versions mentioned.

To be fair, it must be said here that the additional financial expense for purchasing an OCI420 LPB-ClipIn module may not be ‘worthwhile’. However, this depends on the pursued goal. If you only want to log temperatures to get a rough overview of the actual state of the heating system, a more reasonable solution with a corresponding DS18B20 temperature sensor installation would be sufficient.

Hints for connection and configuration of an OCI420-ClipIn are given in chapter 3.8.

3.5 Special Case: Weishaupt Heating Systems

Some Weishaupt devices (see list of successfully tested devices: Weishaupt WTU with WRS-CPU control unit) have RVS23 controllers installed. This controller type has a LPB on which the existing installation of Weishaupt systems is already based: room units, operating units and extension modules are already connected to each other via LPB. The adapter can also be connected to this LPB, but it must be correctly integrated into the existing LPB installation. In general, this isn’t a problem with the default LPB address of the adapter (segment 4, device address 3), but it should be checked again if there are any communication problems.

The Weishaupt devices also seem to have a service socket in addition to the regular operating unit, with two of the four pins provided and led out. According to the statement of a Weishaupt user (Thanks to BSB-LAN user Philippe!), the upper one of the two pins seems to be MB and the lower one seems to be DB.

3.6 Conventional Room Units for the Listed Controllers

The following briefly describes the different room units. These are also manufactured by SIEMENS and branded by the different heating manufacturers. Thus, they can be used across manufacturers, e.g. a corresponding QAA room unit of Elco can be used on a Broetje heater (of course, always provided that it is the right type of room unit). It’s not yet known if there are certain restrictions in individual cases.

As optional ‘local’ accessory parts of the heating system, they are connected to the BSB. That’s why the connector for room units is what you are looking for, when you want to connect the adapter. So if you connect a room unit and adjusted the settings of the specific parameters (e.g. usage and influence of the room unit and room temperature), you can directly access the measured room temp. If you don’t have an external room unit, but you can or want to measure your room temperature(s) in a different way, then you can imitate a room unit by transmitting these measured temperatures via BSB-LAN to the controller and influence the behaviour. For that, look up the function itself and the description of the URL command /Ixxx=yyy.

The following description starts with the room units for the current heating system controllers (RVS and LMS), which are also fully supported by BSB-LAN (so called “Broetje ISR”).

Note: It seems as if the product portfolio has been supplemented with new room units and other accessories. On occasion, I’ll add relevant products here.

3.6.1 QAA55 / QAA58

The QAA55 is the ‘smallest’ and most affordable ISR room unit model. At Broetje it is called “RGB B”, sometimes it is also called “Basic Room Unit”, “ISR RGB” or similar. It is quite limited in functionality and is basically ‘just’ a room temperature sensor with a few additional operating options.

The QAA 55 room unit.

In addition to the optional measurement of the room temperature, it offers a presence button and the options for switching the operating mode and for changing the room set temperature. It only has a small LCD display that shows the current room temperature. It is connected via a two-pole cable to the BSB.

The QAA58 is the wireless version of the QAA55. It is battery operated, the AVS71.390 radio frequency receiver (868 MHz frequency) must in turn be connected to the X60 connection of the boiler controller via cable.

3.6.2 QAA75 / QAA78

The QAA75.61x is the ‘big’ ISR room unit. In addition to the integrated temperature sensor, it has the full functionality of the boiler-side control unit. In addition, there is a presence button and a manual DHW push can be triggered by pressing the DHW mode button for a longer time.

The QAA75.61x room unit.

At Broetje the QAA75.61x is called “room unit RGT”, sometimes it is also called “room unit RGT B Top”, “ISR RGT” or similar. It is also connected by cable to the BSB, with a third connection for the optional backlight available (terminal “G +” on the controller).

The QAA78.61x is the wireless version of the QAA75.61x. It is battery operated, the AVS71.390 radio frequency receiver (868 MHz frequency) must in turn be connected to the X60 connection of the boiler controller via cable. The above named “RGT” is extended by an “F” at Broetje, so it’s “RGTF”.

At this point it has to be mentioned, that obviously two different versions of the QAA75 are available: the already mentioned room unit QAA75.61x and the different looking QAA75.91x.
Whenever I’m referring to the “QAA75” in this manual, I mean the above described model QAA75.61x.

The QAA75.91x seems to offer the same functionality like the QAA75.61x, but it seems to be used only with some types of heating systems by certain manufacturers (e.g. Broetje WMS/WMC C, BMK B, BMR B and Baxi Luna Platinum+). At these types of heating systems, it seems to be used as the operating unit which is located at the housing of the heating system itself, but (in conjunction with an optional adapter, e.g. Broetje “ISR RGA”) could also be used as a room unit. In that case it seems to be still used as the operating unit, just with the additional benefit of the functions of a room unit.

A QAA75.91x operating unit, with optional equipment useable as a room unit.

3.6.3 QAA74

The QAA74 is a pretty new type of room unit at the market, which should/will replace the QAA75 in long term. At Broetje it’s called “ISR RGP” (room unit premium), at Siemens “UI400”. It is equipped with a 3,8” LCD display and a turn/push button for control purposes. Within some specific types of heating system, it’s also used as the main operating unit, named AVS74.

3.6.4 Broetje IDA

The “Broetje IDA” is a room unit which, in addition to an integrated temperature sensor and some functions, also offers a certain range of functions for controlling the heating system via app with a smartphone. A presence button is not available.

IDA is integrated into the domestic WLAN and requires Internet access, if you want to control the unit via app. In the case of purely local use of the room unit (without remote access via the app), no WLAN access is required. Incidentally, the WLAN access also updates the IDA firmware. An interesting analysis of the traffic was made here by FHEM forum member “freetz”.

For connection to the BSB of the boiler controller, a BSB interface (GTW17) must be connected. Interested user must look for “ISR IDA” in this case, so that the GTW17 is included in the package.
For controllers with the communication protocol OpenTherm (e.g. the older controller generation Broetje LMU6x), the OT interface (GTW16) must be used.
IWR-CAN-based controllers (see chapter 3.3) can directly be connected to the service dongle GW05 (WLAN gateway).

The exact functionality and installation steps of IDA are to be taken from the corresponding instructions of the manufacturer.

The parallel use of IDA and BSB-LAN is possible in principle, however, due to the report of a user (Thanks to FHEM-Foums member “mifh”!) a few restrictions regarding the functional scope of BSB-LAN are known:
If IDA is connected to the BSB, then it is the master for the settings or values of

The function of the presence button via BSB-LAN should still be available.

3.6.5 QAA53 / QAA73

The room units QAA 53 and QAA 73 also differ in their functional scope. They are used in the OpenTherm-based LMU6x controllers.
Further information on these room units can be found in the corresponding instructions.

3.6.6 QAA50 / QAA70

In principle, the QAA50 and QAA70 also have the same difference in functionality. These room units are used in the old controller generations, which offers only one PPS connector. When using the adapter parallel to an already existing room unit it’s only possible to read values via BSB-LAN. In that case no values and settings of the heating controller can be changed via BSB-LAN.

A QAA70 room unit.

Further information on these room units can be found in the corresponding instructions.

3.7 Special Accessories: Webserver OZW672 and Servicetool OCI700

For the sake of completeness there should two commercial solutions be mentioned, which offer access to the controller of the heating system.
Thats the webserver OZW672 and the servicetool OCI700.

The webserver OZW672 (Broetje: “ISR OZW”) is connected via bus cable to the controller and with a LAN cable to the network (and, if desired, also to the internet). If desired, one could connect with the fee-based dataportal of Broetje and offers remote access (via PC, tablet or smartphone+app) to the controller.

The OCI700 is the servicetool used by the installation engineer. It is connected to a local computer running a special software and offers an overview of the settings of the controller.

3.8 Retrofitting an LPB by Using an OCI420 ClipIn

If an OCI420 should be connected and used with a LMx controller, the installation and the connection must be made in accordance with the respective operating instructions.

There are, however, a few key points that usually can’t be found in the operating instructions although they are necessary for a successful operation. This mainly concerns the settings that have to be made for the LPB power supply. Furthermore, the LPB device address 1 with segment address 0 must be set and the setting as the time master has to be made.
As always, the following information comes without any guarantee!

If you follow the instructions on the OCI420, you will most likely encounter error 81, which means “short circuit in the LPB bus or missing power supply”. If the OCI420 has been connected correctly, the LPB bus power must be activated in this case. The parameter is “LPBKonfig0”.

The following settings are described for controllers of type LMU64. Except for the parameter numbers, the settings of the bits are identical for other LMx controllers.
For the LMU64, the relevant parameter has the number 604 (for LMU74: parameter number 6006). Here are eight bits (604.0 to 604.7) available to be set as follows (where “0” = OFF and “1” = ON):

604.0 = 0 → time master
604.1 = 1 → time master
604.2 = 1 → distributed bus supply AUTOMATIC
604.3 = 1 → status LPB bus supply: 1 = active
604.4 = 1 → event behavior allowed
604.5 = 0 → domestic hot water allocation
604.6 = 0 → domestic hot water allocation
604.7 = 0 → no priority of LMU request before external power specification

If you call up the ‘overview’ of the LPBKonfig0 settings, however, the bit order is displayed from back to front (from bit 7 to bit 0!) and should be as follows after the successful setting: 00011110.
Furthermore, the following settings have to be made:

605 LPB device address = 1
606 LPB segment address = 0

After successful setting, no error code should occur and the green LED on the OCI420 should flash at regular intervals.

Further on to chapter 4
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