Nibe (KNV) Heating & Cooling (S-Series)
Controls Nibe (KNV) S-Series heat pumps directly via Modbus TCP without a gateway.
Template for Nibe (KNV) S-Series heat pumps via Modbus TCP. Reads temperatures, compressor data, thermal and electrical energy, and operating hours. Controls heating/cooling modes, supply flow setpoints, hot water demand, and curve offsets.
- Protocol
- Modbus TCP
- Connection
- Ethernet, Modbus TCP
- Registers
- 41, read and write
- Brand
- KNV
- Key readings
- Outdoor temperature · Supply and return flow temperatures · Hot water top/bottom temperatures · Compressor state and operating hours · Total thermal power (heating/hot water) · Actual electrical power
- Available commands
- Heatpump operating mode · Target heating/cooling supply flow temperature · Hot water demand · Offset curve HC1
- Compatible models
- S1155 · S1155PC · S1156 · S1156PC · S1255 · S1255PC · S1256 · S1256PC · S2125 · SMO S40
- Last updated
Registers (41)
39 read, 8 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| Actual Outdoor temperature [BT1] | °C | Read | |||
| Actual Hot Water Bottom temperature [BT6] | °C | Read | |||
| Actual Supply Flowtemperature HC1 [BT2] | °C | Read | |||
| State Room temperature HC1 [BT50] | °C | Read | |||
| State Offset Curve HC1 | Read and write | ||||
| State Heat Curve HC1 | Read and write | ||||
| Total Thermal Power Heating | kWh | Read | |||
| Total Operating time direct heater | h | Read | |||
| Actual Return temperature HC1 [BT3] | °C | Read | |||
| Actual Brine Out Flowtemperature [BT11] | °C | Read | |||
| Actual Brine In Flowtemperature [BT10] | °C | Read | |||
| State Compressor | Read | ||||
| Actual Hot Water Top temperature [BT7] | °C | Read | |||
| Total Thermal Power Hot Water | kWh | Read | |||
| Actual Heatpump Flowtemperature [BT12] | °C | Read | |||
| Actual Liquid Line temperature [BT15] | °C | Read | |||
| Average Outdoor temperature 24h [BT1] | °C | Read | |||
| Actual Heatpump Flow Sensor [BF1] | l/m | Read | |||
| State Brine Pump Speed [GP2] | % | Read | |||
| State Compressor Starts | count | Read | |||
| State Circulation pump HC1 [GP10] | % | Read | |||
| State Calculated Supply Flowtemperature | °C | Read | |||
| Actual Electrical Power Compressor | W | Read | |||
| State Compressor Operation hours | h | Read | |||
| State Hot Water Demand | Read and write | ||||
| State Hot Water operation mode | Read | ||||
| State Cooling operation mode | Read | ||||
| State Heatpump Operating prioritisation | Read | ||||
| Actual Flowtemperature Buffer to HC [BT25] | °C | Read | |||
| Actual Current BE3 | A | Read | |||
| Actual Current BE2 | A | Read | |||
| Actual Current BE1 | A | Read | |||
| State Heatpump Operating mode | Read and write | ||||
| Actual Electrical Power | W | Read | |||
| State Hot Water Circulation pump [GP11] | Read | ||||
| State Target Heating Supply Flowtemperature HC1 | °C | Read and write | |||
| State Target Cooling Supply Flowtemperature HC1 | °C | Read and write | |||
| State Alarm number | Read | ||||
| State Active alarm | Read | ||||
| Release Heating at manual mode | Write | ||||
| Release Cooling at manual mode | Write |
Loading registers…
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If a device is not in the library yet, we build the template for free as soon as we have the register data.
Use cases
- Monitor outdoor, supply, and return flow temperatures on a live cloud dashboard to verify heat pump performance remotely.
- Create an alert when the compressor exceeds a defined number of operating hours to schedule preventive maintenance.
- Track total thermal power and actual electrical power over time to calculate and report seasonal coefficient of performance.
- Switch heating and cooling modes remotely based on building occupancy or external scheduling logic.
- Adjust the HC1 offset curve remotely to optimize comfort without an on-site visit.
- Trigger hot water demand activation in coordination with PV surplus to maximize self-consumption.
Installation
Enable Modbus TCP on the Nibe S-Series heat pump via the HMI under menu 7.5.9 Modbus TCP/IP and note the assigned IP address.
Connect the ModbusCloud Gateway to the same local network as the heat pump using an Ethernet cable.
In the ModbusCloud portal, import the Nibe (KNV) S-Series template and assign the heat pump IP address and default Modbus TCP port 502.
Optionally export the full register list from the heat pump HMI to a USB stick to verify register availability for your specific model.
Verify communication by checking that live temperature values and compressor status appear on the ModbusCloud dashboard.
Configure any desired control setpoints such as operating mode or supply flow target temperature and confirm correct write access.
Things to watch for
Why do I see zero or incorrect values for total thermal power or compressor starts?
These registers (e.g. addresses 1575, 1577, 1083) are 32-bit values spanning two consecutive Modbus registers. Ensure the template is configured to read them as 32-bit integers rather than single 16-bit registers.
Can I use this template for Nibe F-Series or Greenline models?
No. The register maps differ significantly between the F-Series, S-Series, and Greenline product families. Use the dedicated F-Series or Greenline template for those models.
How do I find the correct Modbus TCP port and IP address on the heat pump?
Navigate to menu 7.5.9 Modbus TCP/IP on the heat pump HMI display. The IP address and port (typically 502) are shown there. Make sure the gateway and heat pump are on the same subnet.
Do I need an external Modbus gateway module to connect the S-Series?
No. The Nibe S-Series and SMO S40 controller have a built-in Modbus TCP interface. You connect the ModbusCloud gateway directly over Ethernet without any additional hardware.
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