the minimum level of settlement on the internal walls of soot and soot and the possibility of their light removal during preventive cleaning;
almost complete tightness, the consequence of which is the absence of leaks of carbon monoxide;
the minimum level of settlement on the internal walls of soot and soot and the possibility of their light removal during preventive cleaning;
almost complete tightness, the consequence of which is the absence of leaks of carbon monoxide;