11 Oil, gas and solid fuel boilers, in particular low temperature oil-powered boilers; gas condensers; oil and gas powered wall-hung boilers; low temperature gas powered boilers; gas powered boilers; heat pumps; oil and gas burners for boilers, in particular, oil and gas blower burners; solar collectors; storage water heaters; electric water heaters; instantaneous water heaters; heat exchangers; ventilating apparatus for air conditioning, namely, exhaust fans, ducts, louvers; air conditioners; steam generators