Viessmann Heating & Cooling
Controls Viessmann heating and cooling systems via Modbus TCP or RTU gateway.
This template monitors and controls Viessmann Vitotronic heating and cooling systems via Modbus TCP or RTU through the Vitogate 300 gateway. It reads temperatures, pump states, and operation modes while allowing setpoint and mode adjustments for heating circuits and domestic hot water.
- Protocol
- Modbus TCP
- Connection
- Ethernet, Modbus TCP
- Registers
- 16, read and write
- Brand
- Viessmann Vitotronic
- Key readings
- Actual outside temperature · Actual buffer temperature · Actual warm water temperature · Actual flow temperature HC2 and HC3 · Circulation pump states HC2, HC3, warm water · Actual generator temperature
- Available commands
- Operation mode HC2 and HC3 · Operation mode warm water storage · Target temperature warm water · Target temperature HC2 and HC3
- Compatible models
- VT 200-H (HK1S) · VT 200-H (HK1B) · VT 200-H (HK3B) · VT 200-H (HK3S) · VT 100 (GC1) · VT 100 (GC1B) · VT 100 (GC4B) · VT 100 (GC1C) · VT 100 (GC4C) · VT200 (GW1) · VT 200 (GW1B) · VT 300 (GW2B) · VT 300 (GW4B) · VT 300 (GW5B) · VT 100 (CC1E) · VT 100 (CC1I) · VT 200 (CO1E) · VT 200 (CO1I) · VT 300-K (MW1) · VT 300-K (MW1S) · VT 300 (MW1B) · VT 300-K (MW2) · VT 300 (MW2B) · VT 300 (MW2C) · VT 300 (MW3B) · VT 300 (GW6B) · VT 300 (CM1E) · VT 300 (CM1I) · VT 100 (GC7B) · VT 200 (GW7B) · VT 200 (HO1A) · VT 200 (HO1B) · VT 100 (HC1) · VT 100 (HC1A) · VT 100 (HC1B) · VT 200 (HO1) · VT 200 (HO1C) · VT 200 (HO2B/C) · VT 299 (HO1B/HO2B/C) · VT 200 (WO1A) · VT 200 (WO1B) · VT 200 (WO1C) · Vitocrossal · Vitodens · Vitocal · Vitocaldens · Vitoligno
- Last updated
Registers (16)
16 read, 6 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| Actual outside temperature | °C | Read | |||
| Actual buffer temperature | °C | Read | |||
| Actual warm water temperature | °C | Read | |||
| State operation mode HC2 | Read and write | ||||
| State operation mode HC3 | Read and write | ||||
| State operation mode warm water storage | Read and write | ||||
| Actual generator temperature | °C | Read | |||
| State target temperature warm water | °C | Read and write | |||
| Actual flow temperature HC2 | °C | Read | |||
| Actual flow temperature HC3 | °C | Read | |||
| State Circulationpump HC3 | Read | ||||
| State Circulationpump HC2 | Read | ||||
| State Circulationpump warm water | Read | ||||
| State Valve heating / warm water | Read | ||||
| State target temperature HC2 | °C | Read and write | |||
| State target temperature HC3 | °C | Read and write |
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Use cases
- Monitor outside, buffer, and flow temperatures on a live cloud dashboard for remote system oversight.
- Adjust warm water and heating circuit target temperatures remotely without visiting the installation site.
- Create an alert when the buffer temperature drops below a defined threshold for more than 15 minutes.
- Track circulation pump run states for HC2, HC3, and warm water to detect cycling or pump failures early.
- Log generator temperature trends over time to support preventive maintenance scheduling.
- Switch heating circuit operation modes between standby, heating, and reduced mode based on seasonal needs.
Installation
Connect the Vitogate 300 BN/MB gateway to the Vitotronic controller via the LON bus communication module and verify that the LON connection is active.
Configure the Vitogate 300 for Modbus TCP or Modbus RTU communication, setting the desired slave address, baud rate (typically 9600), and parity (even, 8 data bits, 1 stop bit) as specified in the Vitogate documentation.
Wire the ModbusCloud Gateway to the Vitogate 300 using an Ethernet cable for Modbus TCP or a shielded twisted pair cable with correct A/B polarity for Modbus RTU.
Power on both gateways and confirm that the Modbus connection LED on the Vitogate 300 indicates active communication.
Import the Viessmann Heating and Cooling template in the ModbusCloud platform, assign it to your gateway, and set the correct Modbus slave address to match the Vitogate 300 configuration.
Verify that live readings such as outside temperature and pump states appear on the ModbusCloud dashboard before completing the installation.
Things to watch for
Which Modbus communication settings should I use on the Vitogate 300?
The default settings are typically 9600 baud, 8 data bits, even parity, and 1 stop bit. Confirm these in the Vitogate 300 configuration menu and match them exactly on the ModbusCloud gateway.
Some register values appear incorrect or extremely large. What could be wrong?
The Vitogate 300 uses a mix of int16, uint16, and int32 register types. If a 32-bit value is read as two separate 16-bit values, the result will be incorrect. Ensure the template is imported without manual register modifications.
How do I know if my Vitotronic model is compatible with the Vitogate 300?
Consult the official Viessmann Vitogate 300 compatibility list before purchasing. Not all Vitotronic variants support the same register set, and some older models may not be supported at all.
Can I use both Modbus TCP and Modbus RTU with this template?
Yes. The template defines registers that work with both protocols. Choose TCP if the Vitogate 300 is connected via Ethernet, or RTU if you use a serial RS-485 connection to the ModbusCloud gateway.
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