How to connect Nibe S-series heat pump (Modbus) with Reduxi controller
Add a Nibe S-series heat pump to the Reduxi Controller over Modbus and read its values.
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Photo of a tall freestanding indoor heat pump module on a white background. Light grey and silver cabinet with a darker front-left edge, a black plinth at the bottom and a small dark logo mark at the top left of the front. No readable text.
1 Prepare the connection
1.1 Technical documentation
Documents of the manufacturer:
- Nibe professional: search documents – Instructions on the manufacturer web page
- Technical Information: Modbus S-Series (PDF, M12676EN) – Modbus TCP/IP of the NIBE S-series: menus, port, register tables
- MODBUS 40: tips and tricks (PDF) – Settings and connection of the MODBUS 40 accessory (RS485)
1.2 Required equipment
These components connect the Reduxi Controller to the Nibe heat pump:
- Reduxi Controller
- Nibe heat pump with Modbus: S-series with built-in Modbus TCP/IP (software 2.2.1 or later), or a heat pump with the MODBUS 40 accessory (RS485)
- Network connection of the heat pump (Wi‑Fi or Ethernet) for Modbus TCP/IP
- RS485 cable, only for the connection with MODBUS 40
- Laptop or tablet with internet access to configure the device in Reduxi
2 Activate Modbus on the heat pump
Use one of the two connection types. Both are listed for Nibe in the List of supported devices.
2.1 Modbus TCP/IP (S-series)
502.The heat pump accepts connections only from private address ranges (10.x.x.x, 172.16–31.x.x, 192.168.x.x). In menu 7.5.9 you can restrict access to a trusted IP address ("IP address restriction"). If you use it, enter the IP address of the Reduxi Controller.
2.2 Modbus RTU over RS485 (MODBUS 40)
The MODBUS 40 accessory connects the heat pump over RS485 with Modbus RTU. Default settings:
| Parameter | Value |
|---|---|
| Baud rate | 9600 |
| Data bits | 8 |
| Parity | none |
| Stop bits | 1 |
| Slave address |
1 (0x01) for MODBUS 40 version 7 or lower. From version 10 the address can be changed. |
3 Log in to the Reduxi web interface
You can open the Reduxi web interface in two ways:
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Screenshot of three Reduxi mobile app screens side by side, with cyan boxes and number badges 2 to 4. Left screen (dashboard, dark theme): menu icon at top left marked with a box and badge 2; 'reduxi' logo; tabs 'Real time data' (active) and 'Statistics'; price 5.79 € and temperature 3.2 °C; energy flow diagram with a house in the centre (-1.25 kW) and icons with values 69.0 W, 1.3 kW, 1.1 kW (red ring), -165.0 W with 97 % (red ring) and 0.0 W values at the bottom; tabs 'Power' and 'Energy'; bottom navigation: Dashboard, Diagnostics, Device control, Settings. Middle screen (side menu): 'reduxi' logo, 'Number of locations: 1233', heading 'Reduxi device management', entries '+ Add Reduxi location' and 'Reduxi devices' (marked with a box and badge 3), then 'My profile' and 'About app'. Right screen (device page): Back; picture of a black Reduxi controller with two Ethernet ports; status 'Connected'; card 'Update available': 'New update is available for your Reduxi device.' with button 'Download and install update'; card 'Connect to configurator': 'Tunnel connection enables remote access to your Reduxi configurator, without need to be connected to the same local network.' with button 'Activate tunnel connection' (marked with a box and badge 4); card 'Unit details' with field 'Unit ID'.
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Screenshot made of two parts side by side. Left part: Reduxi mobile app screen on a dark background. Top: Back button; picture of a black Reduxi controller with two Ethernet ports and a terminal block; status 'Connected' with a Wi-Fi icon. Card 'Update available': 'New update is available for your Reduxi device.' with button 'Download and install update'. Card 'Connect to configurator' with a key icon: 'Tunnel connection enables remote access to your Reduxi configurator, without need to be connected to the same local network.' and button 'Open configurator', marked with a cyan box and number badge 5. Below: card 'Unit details' with a field 'Unit ID' (value not visible). Right part: Reduxi Configurator opened in a browser, marked with a cyan frame and number badge 6. Header: back arrow, 'Tunnel connection', reload icon. Left sidebar with icons (lightning, chip, lightning bolt, bar chart, gear). Page 'Home' with a green link icon. Green notice: 'New patch available. Click here to apply.' with a close X. Time 09:12:56. Energy flow diagram with a house in the centre (1.700 kW) and icons for grid (0.000 kW), solar (1.700 kW), battery (green, 0.000 kW and 0.800 kW), a device at left (0.900 kW), electric vehicle and a charger or device at bottom. Label 'Energy manager' at the bottom.
http://reduxi.local. You can find the controller's IP address in your router's device list or in the Reduxi app under Reduxi devices.admin · Password: admin (factory default)Text description of this image
Screenshot of the Reduxi Configurator login page in a Chrome browser window. The address bar shows 'Not secure' and 'reduxi.local'; the address bar is marked with a cyan box and an enlarged copy of it (cyan box, text 'Not secure reduxi.local') is shown at the left, connected by a cyan line. Page background: light grey line drawing of a house with solar panels (green), a wall box, an inverter, a car and a charger. Top left: 'reduxi configurator' logo. Login box in the centre with title 'Login', a language selector (English flag, 'English'), a username field and a password field, and a dark 'Login' button.
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Screenshot of the Reduxi Configurator web interface after login, light theme. Top left: 'reduxi configurator' logo. Header bar: 'Home' at left, green 'Connected' status at top right. Left sidebar: expanded section 'Devices' with a list of entries, then collapsed sections 'Manager' and 'Configuration' and 'Settings'. Main area: energy flow diagram. House in the centre with ring, value 24.20 kW. Grid icon at top left, 24.20 kW (red dot on its line). Solar icon at top right, value '-'. Left icon (battery or device), 6.700 kW (green dot on its line). Right icons (battery storage and a device), values '-'. EV charger icon at bottom left, 31.00 kW. A further device icon at bottom right. Label 'Energy manager' below the house.
4 Add the heat pump to Reduxi
Use these steps to add a new heat pump or to edit an existing one.
4.1 Basic settings
Log in locally to the Reduxi Configurator on the controller (see Point 3) and click Add device.
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Screenshot of the Reduxi Configurator device list. Header: reduxi logo with the text Configurator on a light grey background. Section heading Devices with a minus icon. Device entries in order: Elwe 2 (heat pump icon); Fronius SYMO (sun icon); Schrack NA96 (power pylon icon); Sunways Hybrid Inverter (battery with sun icon); Thor (heat pump icon). Below the last entry is an Add device button with a plus icon, marked with a cyan highlight box. The rest of the image to the right is empty white.
Enter the basic settings of the device:
- Device type:
HVAC - Type:
Nibe S-series - Name: a name of your choice, for example Nibe S-series
Then click Next.
4.2 Communication settings
Select the communication channel and enter the device configuration:
| Parameter | Modbus TCP/IP | Modbus RTU (RS485) |
|---|---|---|
| Connection | TCP/IP |
RS485 |
| IP address | IP address of the heat pump (menu 3.1.13) | – |
| Port | 502 |
– |
| Modbus unit ID | Normally 1
|
Normally 1 (slave address of the MODBUS 40) |
| Serial settings | – |
9600 baud, 8 data bits, no parity, 1 stop bit (MODBUS 40 defaults) |
Then enter and select the advanced settings.
4.3 Test communication
Click Test communication at the bottom of the wizard. It reads the Nibe heat pump once and saves nothing. If the test succeeds, click Done: only Done creates the device.
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Screenshot of the bottom button bar of a Reduxi Configurator page. Left: button 'Back'. Right: button 'Test communication' (marked with a cyan box) and dark button 'Done'.
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Screenshot of the Reduxi Configurator page 'Communication channel and device configuration'. Connection *: TCP/IP (dropdown). IP *: 192.168.50.243, with button 'Scan for IP'. Port *: 502, with button 'Test port'. Modbus unit ID *: 1. Buttons at the bottom: Back (left), Test communication and Done (right). The Done button is marked with a cyan box.
5 Check the readings
5.1 Last measurements
After communication is established, check the values under Devices – Nibe S-series in the Reduxi Configurator as an additional test.
5.2 Control by Reduxi
The List of supported devices shows the Nibe Modbus entries with the integration level Read. Reduxi reads the values over Modbus. Strategy commands do not control the heat pump over Modbus.
To control a Nibe heat pump with the operating modes of the SG-ready contacts, see How to connect Nibe heat pump with Reduxi Gateway. Reduxi strategies are described in Strategies for Reduxi controller.
✓ Summary
Preparation (Points 1–2): Open the Nibe documents. In the S-series, activate Modbus TCP/IP in menu 7.5.9. With the MODBUS 40 accessory, activate it in menu 5.2 and connect RS485.
Nibe heat pump (Point 2): Note the IP address of the heat pump (menu 3.1.13). The heat pump uses port 502.
Add to Reduxi (Points 3–4): Log in to the Reduxi web interface. Add the device with type HVAC and Nibe S-series, enter the communication settings and test the communication.
Go live (Point 5): Check the last measurements. The Modbus integration is read only.
→ Common issues
| Issue | Solution |
|---|---|
| Test communication fails over Modbus TCP/IP | Check that Modbus TCP/IP is activated in menu 7.5.9 and that the software is version 2.2.1 or later. Check the IP address and port 502 (see Point 4). If you use the IP address restriction, enter the IP address of the Reduxi Controller (see Point 2). |
| No data over RS485 | Check the A/B polarity (swap A and B to test), the serial settings and the Modbus unit ID (see Point 2). |
| Strategy does not control the heat pump | The Modbus integration is read only (see Point 5). Use the SG-ready connection for control. |
| Open configurator does not open or stays empty | The tunnel is not active yet. Wait about 30 seconds and check that the controller is online. |
Login with admin is rejected |
The password was changed during installation. Ask the installer. The Reduxi account password does not work here. |
reduxi.local does not load |
Your device is not in the same network as the controller. Use the IP address or the tunnel connection. |
| Communication test fails, device shows offline | Check reachability, IP address / port / unit ID, and that the protocol is enabled on the device. |