why the komin and hydraulik reacted as they did
Kominiarz, not komin, komin is a chimney :)
About the brush and about cleaning the chimney, maybe something from here will help:
You rather meant CO (carbon oxide). CO2 (carbon dioxide) is not poisonous.
The problems are:
- there is an obligation to monitor the state of the chimneys and to clean them in multi-family houses, but there is no such an obligation in detached houses
- people tend to block the air vents in winter with rags or whatever they have, thinking that because of the cool air coming to house they are loosing heat and therefore money, not understanding that proper ventilation is needed in the house due to different reasons; there are also, for example, cases when people change old draughty wooden windows into new ones made of PCV and then they suffer from mould on walls - because installing the new tight windows blocked the ventilation system, fresh air is unable to enter the rooms
Why Polish gas companies and administrations do not like these balanced flue boilers - I have no idea.