F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
F24H1/22—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating
F24H1/34—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water chamber arranged adjacent to the combustion chamber or chambers, e.g. above or at side
F24H1/36—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water chamber arranged adjacent to the combustion chamber or chambers, e.g. above or at side the water chamber including one or more fire tubes