給湯器

摘要

PROBLEM TO BE SOLVED: To provide a water heater capable of preventing the substantial deterioration of a bypass ratio when a water supply pressure is low to such an extent that an adequate water passage amount cannot be obtained even when a water amount control valve is adequately opened without using another bypass valve different from the water amount control valve.SOLUTION: A water heater includes a bypass passage 5 which connects a water supply path 3 of the upstream side and a hot water supply path 4 of the downstream side of a heat exchanger 2 heated by a burner 1 and an electrically driven water amount control valve 6 which makes the total water flow amount to the heat exchanger and the bypass path variable. Therein, not only a main valve body 64 which makes the total water flow amount to the heat exchanger 2 and the bypass path 5 variable but also a sub valve body 65 which makes communication opening with the bypass path 5 variable are connected to a valve shaft 63 driven by a motor 62 of the water amount control valve 6. The sub valve body 65 is configured so as to increase the communication opening with the bypass path 5 when the main valve body 64 moves to the side opening more than a predetermined intermediate opening position.