WATER HEATER

PROBLEM TO BE SOLVED: To provide a water heater capable of securing a warming function on the basis of a warming operation while preventing the warming operation from continuing over an excessively long time in a warming operation control during standby for water heating.SOLUTION: When the temperature in a detection passage decreases to a warming operation starting temperature or lower, a warming operation is started and integration of burning time is started (YES in S3, S4, and S5). When the integrated burning time is the set burning time or less (YES in S6), and the temperature in the passage increases to the warming operation stopping temperature or higher (YES in S7), the warming operation is stopped (S8). When the temperature does not increase to the warming operation stopping temperature, and the integrated burning time exceeds the set burning time (NO in S6), restrictions on the upper limit of a burning stage is relaxed and the number of stages is increased (S10). If, in spite of the relaxation of the upper limit, the temperature does not increase to the warming operation stopping temperature within the set burning time, processing of +α increase to a burning amount arithmetic result is executed, in addition to second upper limit relaxation processing (S10).SELECTED DRAWING: Figure 3 【課題】 給湯待機時の保温運転制御において、保温運転が過度に長時間に亘り継続してしまうことを回避しつつ、保温運転に基づく保温機能を担保し得る給湯装置を提供する。【解決手段】 検出路内温度が保温運転開始温度以下まで低下すれば、保温運転を開始し、燃焼時間の積算を開始する（Ｓ３でＹＥＳ，Ｓ４，Ｓ５）。積算燃焼時間が設定燃焼時間以下で（Ｓ６でＹＥＳ）、路内温度が保温運転停止温度以上まで上昇すれば（Ｓ７でＹＥＳ）、保温運転を停止する（Ｓ８）。保温運転停止温度まで上昇せずに設定燃焼時間を超えたときは（Ｓ６でＮＯ）、燃焼段数の上限に係る制限を緩和して段数を増大させる（Ｓ１０）。上限を緩和してなお設定燃焼時間内に保温運転停止温度まで上昇しなければ、再度の上限緩和処理に加えて燃焼量演算結果に＋αの増加処理を行う（Ｓ１０）。【選択図】 図３