Flexit Nordic S4 modbus communication


I am wondering if I could be able to control the ventilation system in my house through Homey.

It can be externally controlled through the modbus-protocol (english instructions starts at page 12): https://www.flexit.no/globalassets/catalog/documents/111398_fdv_117989.pdf

Here are the instructions that I would be able to use: https://www.flexit.no/globalassets/catalog/documents/111400_modbus_nordic_basic.xlsx

The question is, will I be able to use Modbus in Homey? What kind of Modbus RTU should I use? Assuming that TCP/IP is the way to go? Are there Modbus integrations vs homey that could be reused?

Assuming that I would have to write an app to support the RTU?

Grateful for all help and support.


1 Like

Hi there!

I’ve got the same wish to get an app to Flexit Nordic S4 via modbus communication.

I’ve asked the developer of NibePi to look into this.
I believe it can be done, but I have too little knowledge to help you out.

Since I have a Nibe S1255 that will fully support modbus TCP/IP anytime soon I think its possible.
Probably by doing it over MQQT.

In other words, by using a Raspberry Pi (Zero or whaterver) and a RS485 HAT
then install NodeRed and and configure it (or re-do) the NibePi to fit the needs of FlexIT S4 Nordic, then to send via MQQT to the Homey.
Thats how the Nibe F-users do it (One can also use the User Interface of NodeRed in the Raspberry)

I’ve let my S1255 to be a guinea pig for the development of the upcoming version that has the option of TCP/IP, but the progress of development has been slow due to Covid-19. (The developer has been busy feeding his 3d-printers for hospital equipments, making more than 1000 visirs…)
Hopefully the new version of NibePi (supporting nodered/modbus fully) will see the light within weeks (its in beta-version now)

if you get anymore info, please reply here or send me a PM. :slight_smile: