| 摘要 |
PROBLEM TO BE SOLVED: To provide a water heater for melting snow constituted to prevent the occurrence of dew condensation caused by drop of an exhaust gas temperature. SOLUTION: A heat exchanger 5 using a wall of a combustion chamber 3 to which combustion gas generated in a burner 2 is fed, and a wall of a combustion gas passage 4 as heat exchange parts, is provided in a can 1, and a radiator 6 is connected to the can 1 through a forward pipe 7a and a return pipe 7b. A by-pass passage 10 is connected between the forward pipe 7a and the return pipe 7b, and the forward pipe 7a is provided with a circulating pump 8 and a water flow valve 11 to constitute a hot water circulating circuit. Hot water discharged to the forward pipe 7a from the heat exchanger 5, and water flowing to the by-pass passage 10 from the return pipe 7b, are mixed at a mixing ratio set in the water flow valve 11 and fed to the radiator 6. When a hot water temperature sensor 9 detecting a hot water temperature in the can 1 detects a lower reference temperature, the water flow valve 11 is driven to the closing side to reduce the amount of hot water discharge from the heat exchanger 5, and the hot water temperature in the can 1 is raised to prevent the temperature drop of the heat exchanger 5. COPYRIGHT: (C)2008,JPO&INPIT
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