| 摘要 |
PURPOSE:To positively burn burners to prevent the burners from being ignited or extinguished unintentionally by providing the titled hot water supplier with two burners having different capabilities, and burning these two burners alternaitively independently or both simimultaneously in accordance with a required thermal load thereby to carry out a proportional control. CONSTITUTION:Two burners 2 and 3 having different capabilities are disposed in a heat exchanger 1, and the combustion pattern of each burner is set beforehand based on a required thermal load calculated from the temperature of inlet water and the flow quantity of the same. In a case where a burner 3 of a small capability is selected, when a determined combustion quantity is less than a predetermined combustion quantity set beforehand, opening and closing of an electromagnetic valve 9 of the burner are repeated in a period set in accordance with the required thermal load to burn the burner intermittently to control the quantity of heat. When it is more than the predetermined combustion quantity, the quantity of gas is varied to control the quantity of heat. When the burner 2 on a large capability side is selected, the quantity of gas is varied by a proportional control valve 7 to control the quantity of heat. Further, when both burners 2 and 3 are employed at the same time, the quantity of gas is varied for every quantity of heat determined, by means of proportional control valves 6 and 7 of both burners 2 and 3 to control the quantity of heat.
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