PROBLEM TO BE SOLVED: To provide a water heater capable of efficiently dispersing fine bubbles to the entire bathtub.SOLUTION: A water heater includes: an air pump 68 for pumping air to a bath adaptor 61 having a porous body 67a for discharging the air into hot water inside a bathtub 31 as fine bubbles an air pipe 69 in which the air flows to the bath adapter 61 a bath outgoing pipe 29 and a bath returning pipe 30 for forming a bath circulation circuit 60 a bath circulation pump 23 for circulating the hot water a bath heat exchanger 24 for heating the hot water flowing in the bath circulation circuit 60 and control means 51 for operating the bath circulation pump 23 and the air pump 68, and for executing a supply operation for discharging the fine bubbles into the hot water inside the bathtub 31. As a pressure of the hot water pumped to the bath circulation circuit 60 by the bath circulation pump 23 in the supply operation is variable, in accordance with a condition of the water heater 100 being installed, the fine bubbles can be generated from an outer surface of the porous body 67a without excess or deficiency, and they can be dispersed inside the bathtub 31 efficiently.COPYRIGHT: (C)2016,JPO&INPIT【課題】浴槽内の全体に効率よく微細気泡を拡散させることが可能な給湯機を提供すること。【解決手段】空気を微細気泡として浴槽31内の湯水に放出する多孔質体67aを有する風呂アダプタ61に、空気を圧送する空気ポンプ68と、空気が風呂アダプタ61へと流れる空気配管69と、風呂循環回路60を形成する風呂往き管29及び風呂戻り管30と、湯水を循環させる風呂循環ポンプ23と、風呂循環回路60を流れる湯水を加熱する風呂熱交換器24と、風呂循環ポンプ23と空気ポンプ68とを動作させ、浴槽31内の湯水に微細気泡を放出させる供給運転を実行する制御手段51と、を備え、供給運転における、風呂循環ポンプ23によって風呂循環回路60へ圧送する湯水の圧力が、可変であることで、給湯機100が設置される条件に合わせて、多孔質体67aの外表面から、微細気泡を過不足なく発生させ、効率よく浴槽31内に拡散させることができる。【選択図】図1
