Wolf
CGB-2 boilers and BWL-1S heat pumps with ISM7i Modbus TCP KNX integration
Wolf (Mainburg, Bavaria, Germany — founded 1961) manufactures gas condensing boilers (CGB-2 series), air-source heat pumps (BWL-1S), and mechanical heat recovery ventilation units (CWL-2) for residential and light commercial buildings. Wolf holds a strong position in the German new-build and renovation market, with a complete heating system portfolio from gas condensing through to hybrid heat pump and solar thermal. The ISM7i Internet Service Module is the key integration component — it adds Modbus TCP/IP connectivity to Wolf CGB-2 boilers, enabling KNX integration via a Modbus TCP-to-KNX gateway without any proprietary middleware.
Role in our panels
How we use Wolf
The Wolf CGB-2 gas condensing boiler (output range 14–35 kW) with the ISM7i Internet Service Module exposes all operating parameters via Modbus TCP: flow temperature setpoint (Register 1, Holding Register, read/write, 0.1°C resolution), operating mode (Register 100: 0=off, 1=heating, 2=DHW, 3=heating+DHW), fault code (Register 200, read-only), and cumulative gas consumption (Register 201, kWh, read-only). The ISM7i connects to the boiler's service bus and presents a Modbus TCP server on the LAN (port 502, unit ID 1). This is the same ISM7i used for Wolf web portal (wolf.smartguide.de) connectivity. KNX integration of the Wolf CGB-2 uses an Intesis IN701KNX Modbus TCP-to-KNX gateway, mounted in the electrical panel. Configuration via IntesisBox Configurator (Windows): add Wolf ISM7i as Modbus TCP device (IP address, port 502, unit ID 1), map registers to KNX group addresses. Typical GA mapping: GA 8/0/0 (flow setpoint, DPT 9.001, read/write), GA 8/0/1 (operating mode, DPT 5.001, read/write), GA 8/0/4 (fault alarm, DPT 1.005, read), GA 8/0/5 (gas consumption today, DPT 13.013, read). ETS6 then uses these group addresses for boiler control from KNX room controllers and visualisation. The Wolf BWL-1S air/water heat pump (7–13 kW, monobloc) includes an SG Ready dry-contact interface (S1 and S2 terminals) for PV surplus integration. Two KNX relay actuator channels (MDT BJ65-AB08.01) connect to S1/S2: KNX sends relay-close telegram when PV surplus exceeds threshold, activating raised setpoint mode (S1 closed) or DHW boost mode (S1+S2 closed). The Wolf BWL-1S does not have Modbus — SG Ready relay inputs are the only KNX integration path for heat pump mode control. The Wolf CWL-2 mechanical heat recovery ventilation unit includes a Modbus RTU interface (RS-485, 9600 baud, 8N1) for demand-controlled ventilation integration. Register map: ventilation speed (Register 1, 0–100%), bypass mode (Register 2), filter alarm (Register 10). A Modbus RTU-to-TCP converter (e.g. Moxa NPort 5110) bridges CWL-2 Modbus RTU to Modbus TCP, after which the Intesis IN701KNX gateway maps CWL-2 registers to KNX group addresses alongside the CGB-2 boiler — all heating and ventilation in one KNX gateway configuration.
Wolf integrates with KNX via the ISM7i Internet Service Module (adds Modbus TCP to CGB-2 boilers). The Intesis IN701KNX Modbus TCP gateway reads Wolf registers and maps them to KNX group addresses: GA 8/0/0 (flow setpoint DPT 9.001), GA 8/0/1 (operating mode DPT 5.001), GA 8/0/4 (fault alarm DPT 1.005), GA 8/0/5 (gas consumption today DPT 13.013). Wolf BWL-1S heat pump uses dry-contact SG Ready inputs (S1/S2) driven by KNX relay actuators for PV surplus control.
Used in these project types
Wolf products
Key components we install
CGB-2 Boiler
Gas condensing wall-hung boiler, 14–35 kW, ErP A-rated. Requires ISM7i module for Modbus TCP connectivity. All operating parameters (flow setpoint, mode, fault, gas consumption) accessible via Modbus Holding Registers. Standard Wolf boiler for German residential new-build and renovation. Compatible with Wolf solar thermal and DHW cylinder systems.
BWL-1S HP
Monobloc air/water air-source heat pump, 7–13 kW, SCOP 4.0 (A7/W35). SG Ready dry-contact terminals (S1, S2) for PV surplus and grid demand response. KNX relay actuator channels close S1/S2 for raised setpoint or DHW boost. No Modbus interface — SG Ready relay inputs are the only KNX integration path.
ISM7i Module
Wolf Internet Service Module providing Modbus TCP and internet (wolf.smartguide.de) connectivity for CGB-2 boilers. Connects to Wolf service bus inside the boiler. Presents Modbus TCP server on LAN (port 502, unit ID 1). Required hardware for all Wolf Modbus/KNX integration projects. One ISM7i per boiler — cascade plants require one ISM7i per boiler module.
CWL-2 HRV
Mechanical heat recovery ventilation unit with Modbus RTU (RS-485) interface. Ventilation speed, bypass mode, filter alarm via Modbus registers. KNX integration via Moxa NPort (RS-485 to TCP) + Intesis IN701KNX. Enables CO2/humidity demand-controlled ventilation from KNX room sensors.
SFP Solar
Wolf flat-plate solar collector for solar thermal DHW and heating support. Paired with Wolf solar controller (SM2-2) which connects to ISM7i for solar yield monitoring via Modbus. KNX group address maps solar yield (today, total) from ISM7i Modbus register for energy dashboard display.
Wolf FAQ
What is needed to integrate Wolf CGB-2 with KNX?
Two components: (1) Wolf ISM7i Internet Service Module — plugs into the CGB-2 service bus inside the boiler, adds Modbus TCP on the LAN. Order ISM7i separately (article number 8613600). (2) Intesis IN701KNX Modbus TCP-to-KNX gateway — mounted in the electrical panel, configured with Wolf ISM7i IP address and register list, outputs KNX group addresses. ETS6 then uses the mapped group addresses. Total cost: ISM7i approx. €120–150, Intesis IN701KNX approx. €250–350. Total integration time: 2–4 hours for configuration and ETS6 parameterisation.
Which Wolf Modbus TCP registers are most important for KNX integration?
The key registers in Wolf ISM7i Modbus TCP (Holding Registers, unit ID 1): Register 1 = flow temperature setpoint (0.1°C, read/write, range 200–800 = 20.0–80.0°C), Register 100 = operating mode (0=off, 1=heating, 2=DHW, 3=heating+DHW, read/write), Register 200 = fault code (read-only, 0=no fault), Register 201 = gas consumption today (kWh, read-only). Full Wolf ISM7i Modbus register map is available in the Wolf technical documentation (ISM7i Installation and Operating Manual, Appendix C).
Can Wolf BWL-1S heat pump be controlled by KNX for PV self-consumption?
Yes, via SG Ready relay inputs. The BWL-1S has S1 and S2 terminals accepting dry-contact signals. Wire two KNX relay actuator channels to S1 and S2. KNX energy management logic: when PV surplus > 2 kW, send telegram closing S1 channel → BWL-1S raises heating setpoint by 3°C (stores excess energy as heat). When PV surplus > 5 kW, close both S1 and S2 → BWL-1S enters maximum output mode (DHW boost). When PV generation drops, KNX opens both contacts → BWL-1S returns to standard schedule. This is the Wolf-approved SG Ready integration method.
Need a panel with Wolf components?
We select, procure, assemble and certify. Free initial consultation.
Request consultation →