In local forum I was adviced to refill the system with R290. Usually components in R407C units match quite nicely for R290. Especially when the compressor is capillary feed.
So I made a quick test setup with some indoor unit as an evaporator and it seemed to work fine. Got hot or cold depending on the 4-way valve position.
In this first setup the system was filled from 'official' R290 refrigerant bottle that had 370 grams content.
After testing I was convinced and made a stand outside of the house.
Extracted Nibe 410P refrigerant loop pipes and brazed new piping.
