HOT WATER SUPPLYING/HEATING DEVICE

PROBLEM TO BE SOLVED: To provide a hot water supplying/heating device capable of reducing repeating frequency of combustion on/combustion off in on/off combustion control by preventing a combustion amount of a heat source machine from being excessive.SOLUTION: A hot water supplying/heating device 3 includes a control unit 45 having a high combustion mode for performing combustion by using all or the most part of a plurality of combustion stages of an auxiliary heat source machine 5, and performing proportional combustion control or on/off combustion control of the auxiliary heat source machine 5 according to a heating load of a hot water heating terminal 10, and an intermediate combustion mode set to a combustion area narrower than a combustion area of the high combustion mode and wider than a non-combustion area, during a heating operation. The control unit 45 switches a mode from the high combustion mode to the intermediate combustion mode when the number of times of on and off control of the on/off combustion control in a set time period exceeds the set number of times, or when one cycle time of the on/off combustion control is shorter than the set time. 【課題】給湯暖房装置において、熱源機の燃焼量過多を防止して、オンオフ燃焼制御の燃焼オン・燃焼オフの繰り返し頻度を低減可能なもの等を提供することである。【解決手段】給湯暖房装置３は、暖房運転中に、補助熱源機５の複数の燃焼段の全て又は大部分を使用して燃焼を行うと共に温水暖房端末１０の暖房負荷に応じて補助熱源機５を比例燃焼制御又はオンオフ燃焼制御する大燃焼モードと、この大燃焼モードの燃焼領域よりも狭く且つ非燃焼領域よりも広い燃焼領域に設定する中燃焼モードとを有する制御ユニット４５を備え、制御ユニット４５は、設定期間中におけるオンオフ燃焼制御のオンオフ回数が設定回数を超えた場合、又は、オンオフ燃焼制御の１サイクル時間が設定時間を下回った場合、大燃焼モードから中燃焼モードに切り換える。【選択図】図５