Thanks for reaching out to us @Nelzon here. I would be happy to try and assist.
You can find out all our compatibility information and our compatibility checker on the page Nest thermostat compatibility here.
Generally our thermostats are not compatible with biomass systems as they use solid fuel like wood or pellets that have to be fed to the system and heating can't just be turned on or off, as opposed to something like a gas boiler.
It may work with some auto feeding pellet systems but I can't give any recommendations, an installer or Nest Pro has to determine if it can be made to work with a particular system. Generally it is not recommended or compatible with those types of systems. Let me know if there's anything else I can try and assist with.
