Heating installations using solid, liquid or gas fuels or electricity, central heating boilers, boilers for heating installations, electric radiators for heating; heat exchangers, not parts of machines; ceramic stoves, and kitchen stoves in the nature of cooking stoves; solar thermal collectors for heating; steam, gas and fog generators, and steam furnace boilers, other than parts of machines; acetylene generators, oxygen generators in the nature of oxygen generator for processing water by in...