Nordic Flexit

Use cases

• Monitor supply and extract air temperatures on a live dashboard to verify heat recovery performance.
• Create an alert when the alarm indication register signals a fault on the Nordic Flexit unit.
• Track filter operating hours remotely and notify the end user when a filter replacement is due.
• Adjust home and away temperature setpoints remotely without visiting the installation site.
• Trigger fireplace ventilation mode from the cloud when coordinating with a wood stove installation.
• Log outside air temperature alongside supply air temperature to evaluate heat recovery efficiency over time.

Installation

1. 1Connect the Modbus RTU wiring (A and B terminals) from the Nordic Flexit unit to the RS485 port on your ModbusCloud gateway (MCG or MLP series).
2. 2Verify that the Nordic Flexit is configured with slave address 1, baud rate 9600, 8 data bits, even parity, and 1 stop bit.
3. 3Match the same serial port settings (9600, 8E1) on the ModbusCloud gateway RS485 port configuration.
4. 4Import the Nordic Flexit template from the ModbusCloud template library and assign it to the correct gateway and port.
5. 5Set the Comfort Button register (address 2040) to 1 in the ModbusCloud interface to enable write access to all control registers.
6. 6Confirm live data is appearing on the dashboard by checking that temperature values and filter hours are reading correctly.

Things to watch for

01

Why are all write commands to the Nordic Flexit being ignored?

All write registers only function when the Comfort Button at Modbus address 2040 is set to 1. Enable this register first before attempting any control operations.

02

Temperature readings show unrealistic values. What is wrong?

Temperature and filter hour registers use float32 format, which spans two consecutive 16-bit registers. Ensure your gateway is configured for the correct byte order and word order (typically big-endian) to decode float32 values properly.

03

The gateway cannot communicate with the Nordic Flexit unit. What should I check?

Verify that the serial settings match exactly: baud rate 9600, 8 data bits, even parity, 1 stop bit, and slave address 1. Also check that the A and B wires are not swapped and that a termination resistor is present if the cable run is long.

04

Can I use this template with the Nordic Flexit S4 model?

Yes. This template is compatible with both the standard Nordic Flexit and the Nordic Flexit S4. The register map and communication settings are the same.

Registers (13)

10 read / 6 write

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