| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce noise by a combustion fan in a heating operation, in a composite heat source machine comprising a first heat exchanger 4 heating a heat medium by heat exchange with exhaust gas of a burner 3, and a second heat exchanger 11 for supplying hot water, composed of a liquid-liquid heat exchanger, capable of changing rotational frequency of the combustion fan 8 according to an opening of a gas proportional valve 6, and increasing the number of burning unit burners by one stage when a required burning capacity becomes more than a burning capacity achieved with a controlled maximum opening of the gas proportional valve, in such a state that the number of burning unit burners 3a constituting the burner is not maximum. <P>SOLUTION: The controlled maximum opening of the gas proportional valve 26 in the heating operation is determined to be smaller than that in a hot water supplying operation. <P>COPYRIGHT: (C)2007,JPO&INPIT |
