【０００１】
【発明の属する技術分野】
本発明は、給湯熱交換器と追い焚き熱交換器とが一体化され、これら給湯熱交換器と追い焚き熱交換器とを共通に燃焼加熱するバーナが設けられている一缶二水路タイプの風呂給湯器に関するものである。
【０００２】
【従来の技術】
図３には一缶二水路風呂給湯器（器具）のモデル例が実線により示されている。この器具は、器具ケース１内に燃焼室２を有し、この燃焼室２内にはバーナ３が設けられている。バーナ３には該バーナ３へ燃料ガスを導くためのガス供給通路４が接続され、このガス供給通路４には通路の開閉を行う電磁弁５，６と、弁開度によって燃料ガスの供給量を制御する比例弁８とが介設されている。
【０００３】
上記バーナ３の上方には給湯熱交換器１０が設けられ、この給湯熱交換器１０の入側には給水通路１１の一端側が接続され、給水通路１１の他端側は外部配管を介して水供給源に接続されている。給湯熱交換器１０の出側には給湯通路１２の一端側が接続され、給湯通路１２の他端側は外部配管を介して台所やシャワー等の給湯場所に連通されている。
【０００４】
上記給湯熱交換器１０の上側には追い焚き熱交換器１４が給湯熱交換器１０と一体的に設けられ、この追い焚き熱交換器１４の入側には通路１５の一端側が接続され、この通路１５の他端側は循環ポンプ１６の吐出口に接続され、この循環ポンプ１６の吸入口には戻り管１８の一端側が接続され、この戻り管１８の他端側は外部配管と循環金具１９を介して浴槽１７に連通されており、追い焚き熱交換器１４の出側には往管２０の一端側が接続され、往管２０の他端側は外部配管と循環金具１９を介して浴槽１７に連通されている。上記戻り管１８と循環ポンプ１６と通路１５と追い焚き熱交換器１４と往管２０とにより浴槽１７の浴槽湯水を追い焚き循環させるための追い焚き循環通路２１が構成されている。
【０００５】
上記給湯通路１２と追い焚き循環通路２１の通路１５を連通接続する注湯通路２２が設けられており、この注湯通路２２には通路の開閉を行う電磁弁等により構成された注湯制御手段２４が介設されている。上記給湯通路１２と注湯通路２２と追い焚き循環通路２１によって給湯熱交換器１０で作り出した湯を浴槽１７に落とし込む湯張り通路が構成されている。
【０００６】
上記バーナ３よりも下方側の燃焼室２には燃焼ファン２５が介設された給気通路２６が連通接続されている。また、追い焚き熱交換器１４よりも上方側の燃焼室２にはバーナ３の燃焼によって生じた排気ガスを外部に送出するための排気通路２７が連通接続されている。
【０００７】
なお、図３に示す２８は給水通路１１を流れる通水流量を検出する水量センサを表し、３０は給水通路１１の湯水温度を検出する入水サーミスタを表し、３１は給湯熱交換器１０から流れ出る湯水温度を検出する給湯熱交サーミスタを表し、３２は浴槽水位を水圧により検出する水位センサを表し、３３は追い焚き循環通路２１の湯水温度を風呂温度として検出する風呂温度センサを表し、３４は追い焚き循環通路２１の通水水流を追い焚き熱交換器１４の通水水流として検出する循環水流検出手段である水流スイッチを表している。
【０００８】
この一缶二水路風呂給湯器には給湯や、湯張りや、追い焚きや、保温等の器具運転を制御する制御装置３５が設けられ、この制御装置３５にはリモコン３６が信号接続されている。リモコン３６には給湯温度を設定する給湯温度設定手段や、風呂の温度を設定する風呂温度設定手段や、風呂の水位を設定する水位設定手段等が設けられている。
【０００９】
上記制御装置３５は給湯運転を次のように制御する。例えば、台所やシャワー等の給湯栓（図示せず）が開栓され、水量センサ２８が予め定めた給湯運転作動流量以上の通水流量を検知すると、燃焼ファン２５の駆動を開始し給気通路２６を介してバーナ３に給気を供給すると共に、電磁弁５，６を開けてバーナ３に燃料ガスを供給し、バーナ３の燃焼を開始させ、給湯される湯の温度がリモコン３６に設定されている給湯設定温度となるようにバーナ３の燃焼熱量制御および燃焼ファン２５の回転制御を行い、給水通路１１から供給された水を給湯熱交換器１０がバーナ３の燃焼火炎の熱により加熱して湯を作り出し、その湯を給湯通路１２を介して給湯する。そして、給湯栓が閉められ、水量センサ２８が通水停止を検知したときに、電磁弁５，６を閉弁してバーナ３の燃焼を停止し、その後、予め定めた期間燃焼ファン２５の継続駆動を行わせ、次の給湯運転に備える。
【００１０】
また、湯張り運転を行うときには、例えば、図４のフローチャートに示すように、まず、循環ポンプ１６を予め定めた期間（例えば、１分間）駆動し（ステップ１０１）、その循環ポンプ１６の駆動による追い焚き循環通路２１の循環水流が水流スイッチ３４によって検出されたか否かを判断する（ステップ１０２）。浴槽１７内に湯水がない、又は、浴槽１７の水位が循環金具１９よりも下側の水位であるときには、追い焚き循環通路２１内に湯水はないし、循環ポンプ１６を駆動しても追い焚き循環通路２１内に湯水を引き込むことは不可能であり、追い焚き循環通路２１内に湯水は循環しないので、水流スイッチ３４により追い焚き循環通路２１の循環水流が検出されなかったときには、浴槽１７に水がない又は浴槽１７の水位が循環金具１９よりも低いと判断し、注水制御手段２４を開弁し、給湯熱交換器１０で上記給湯運転と同様に湯を作り出し、その湯を給湯通路１２と湯張り通路２２と追い焚き循環通路２１とを順に介して浴槽１７に注湯し、水量センサ２８により検出される注湯流量に基づいて検出される湯張り開始時からの注湯量が予め定められたｘリットル（例えば、１０リットル）に達したときに注湯制御手段２４を閉止する（ステップ１０３）。
【００１１】
そして、上記同様に、循環ポンプ１６を駆動し（ステップ１０４）、循環ポンプ１６による循環水流が水流スイッチ３４によって検出されたか否かを判断し（ステップ１０５）、水流スイッチ３４によって循環水流が検出されなかったときには予め定めたｙリットル（例えば、１０リットル）を注湯し（ステップ１０６）、再度、循環ポンプ１６を駆動し（ステップ１０７）、循環水流の有無を判断し（ステップ１０８）、水流スイッチ３４によって循環水流が検出されなかったときには予め定めたｚリットル（例えば、５リットル）を注湯する（ステップ１０９）。
【００１２】
さらに、循環ポンプ１６を駆動し（ステップ１１０）、循環水流の有無を判断し（ステップ１１１）、循環水流が検出されなかったときには浴槽１７の水位が循環金具１９よりも低いと判断し、この場合には、浴槽１７の水位が循環金具１９よりも上側となるのに十分な注湯量を湯張り開始時から浴槽１７に落とし込んでいるのにも拘らず、浴槽水位が循環金具１９よりも上側とならないのは異常であると判断し、エラー信号を出力する（ステップ１１６）。
【００１３】
上記循環水流の有無の判断動作時に（ステップ１０２，１０５，１０８，１１１）、水流スイッチ３４によって循環水流を検出したときには、浴槽１７の水位が循環金具１９よりも上側となり、水位センサ３２によって水位検出を行うことが可能となったと判断し、水位センサ３２により浴槽水位を検出し（ステップ１１２）、検出された浴槽水位がリモコン３６に予め設定された浴槽水位であるか否かを判断する（ステップ１１３）。浴槽水位が浴槽設定水位に達していないと判断したときには、給湯熱交換器１０の湯を上記同様に浴槽１７に注湯し水位センサ３２によって浴槽水位を監視し（ステップ１１４）、浴槽水位が設定水位に達したと判断したときに、注湯制御手段２４を閉止して湯張り運転を終了する（ステップ１１５）。
【００１４】
さらに、追い焚き運転を行うときには、循環ポンプ１６を駆動し、浴槽１７から戻り管１８と循環ポンプ１６と通路１５と追い焚き熱交換器１４と往管２０とを順に介して浴槽１７に戻る追い焚き循環経路で浴槽湯水を循環させると共に、バーナ３を燃焼させ該バーナ３の燃焼火炎の熱によって追い焚き熱交換器１４で浴槽湯水の追い焚きを行い、風呂温度センサ３３により検出される風呂温度がリモコン３６に設定されている風呂設定温度に達したときにバーナ３の燃焼を停止し、また、循環ポンプ１６を停止して追い焚き運転を終了する。
【００１５】
さらに、保温運転を行う場合には、例えば、上記追い焚き運転の終了後、予め定めた時間間隔（例えば、３０分間隔）毎に循環ポンプ１６を駆動し、風呂温度センサ３３により風呂の温度を検出し、この検出した風呂の温度が風呂設定温度から予め定めた許容温度を越えて低いときには、バーナ３を燃焼させ、浴槽湯水の追い焚きを行って風呂の湯温を設定温度に高めて風呂の保温を行う。
【００１６】
【発明が解決しようとする課題】
ところで、湯張り運転を行うときには、上記の如く、まず、循環ポンプ１６を駆動して該循環ポンプ１６の駆動による追い焚き循環通路２１の循環水流の有無によって追い焚き熱交換器１４内に湯水が有るか否かを判断してから（図４に示すステップ１０１，１０２）、注湯を開始していた。このように、従来では、湯張り開始時に循環ポンプ１６を駆動させなければ追い焚き循環通路２１（追い焚き熱交換器１４）内の湯水の有無（つまり、浴槽１７の水位が循環金具１９よりも上側であるか否か）を判断できなかったため、湯張り開始時に追い焚き循環通路２１内に湯水がない場合にも循環ポンプ１６を駆動させなければならず、このようなときには循環ポンプ１６は空運転となり、無駄な動作であるし、このような空運転が度重なって行われると、循環ポンプ１６の故障を招き易くなるという問題が生じる。
【００１７】
本発明は上記課題を解決するために為されたものであり、その目的は、追い焚き熱交換器内の湯水の有無を予め検知することが可能な一缶二水路風呂給湯器を提供することにある。
【００１８】
【課題を解決するための手段】
上記目的を達成するために、この発明は次のような構成をもって前記課題を解決する手段としている。すなわち、第１の発明は、給水通路から供給された水を加熱して給湯する給湯熱交換器と、追い焚き循環通路を介して供給された浴槽湯水を加熱して浴槽湯水の追い焚きを行う追い焚き熱交換器とが設けられており、上記給湯熱交換器と追い焚き熱交換器は一体化され、これら給湯熱交換器と追い焚き熱交換器を共通に燃焼加熱するバーナとを備えた一缶二水路風呂給湯器において、給湯単独運転が開始されてからの給湯熱交換器の熱効率の変化を監視する熱効率変化監視部と；給湯単独運転の開始直後の時間の経過に対する上記熱効率変化監視部に監視された給湯熱交換器の熱効率の変化の傾きが予め定めたしきい値よりも大きいときには追い焚き熱交換器内に湯水が無いことを示す水無し信号を出力し、上記熱効率の変化の傾きが上記しきい値以下であるときには追い焚き熱交換器内に湯水が有ることを示す水有り信号を出力する追い焚き熱交換器湯水有無判断部と；が設けられている構成をもって前記課題を解決する手段としている。
【００１９】
第２の発明は、給水通路から供給された水を加熱して給湯する給湯熱交換器と、循環ポンプの駆動により追い焚き循環通路を介して供給された浴槽湯水を加熱して浴槽湯水の追い焚きを行う追い焚き熱交換器と、上記循環ポンプの駆動による追い焚き熱交換器の循環水流を検出する循環水流検出手段と、上記給湯熱交換器で作られた湯を浴槽に落とし込むための湯張り通路とが設けられており、上記給湯熱交換器と追い焚き熱交換器は一体化され、これら給湯熱交換器と追い焚き熱交換器を共通に燃焼加熱するバーナとを有し、上記循環ポンプを駆動し循環水流検出手段によって追い焚き熱交換器内の湯水の有無を判断してから給湯熱交換器で作られた湯を湯張り通路を通して浴槽に落とし込む湯張り機能を備えた一缶二水路風呂給湯器において、給湯単独運転が開始されてからの給湯熱交換器の熱効率の変化を監視する熱効率変化監視部と；給湯単独運転の開始直後の時間の経過に対する上記熱効率変化監視部に監視された給湯熱交換器の熱効率の変化の傾きが予め定めたしきい値よりも大きいときには追い焚き熱交換器内に湯水が無いことを示す水無し信号を出力し、上記熱効率の変化の傾きがしきい値以下であるときには追い焚き熱交換器内に湯水が有ることを示す水有り信号を出力する追い焚き熱交換器湯水有無判断部と；上記水無し信号が出力された後に湯張り開始指令が発せられたときには、循環ポンプと循環水流検出手段を利用した追い焚き熱交換器内の湯水の有無の判断を行わずに、給湯熱交換器の湯を湯張り通路を通して浴槽に落とし込む湯張り制御部と；が設けられている構成をもって前記課題を解決する手段としている。
【００２０】
第３の発明は、給水通路から供給された水を加熱して給湯する給湯熱交換器と、循環ポンプの駆動により追い焚き循環通路を介して供給された浴槽湯水を加熱して浴槽湯水の追い焚きを行う追い焚き熱交換器と、上記循環ポンプの駆動による追い焚き熱交換器の循環水流を検出する循環水流検出手段と、上記給湯熱交換器で作られた湯を浴槽に落とし込むための湯張り通路とが設けられており、上記給湯熱交換器と追い焚き熱交換器は一体化され、これら給湯熱交換器と追い焚き熱交換器を共通に燃焼加熱するバーナとを有し、上記循環ポンプを駆動し循環水流検出手段によって追い焚き熱交換器内の湯水の有無を判断してから給湯熱交換器で作られた湯を湯張り通路を通して浴槽に落とし込む湯張り機能を備えた一缶二水路風呂給湯器において、給湯単独運転が開始されてからの給湯熱交換器の熱効率の変化を監視する熱効率変化監視部と；給湯単独運転の開始直後の時間の経過に対する上記熱効率変化監視部に監視された給湯熱交換器の熱効率の変化の傾きが予め定めたしきい値よりも大きいときには追い焚き熱交換器内に湯水が無いことを示す水無し信号を出力し水無しフラグを立て、熱効率の変化の傾きが上記しきい値以下であるときには追い焚き熱交換器内に湯水が有ることを示す水有り信号を出力し上記水無しフラグを倒す追い焚き熱交換器湯水有無判断部と；湯張り開始指令が発せられたときに水無しフラグが立っているときには、循環ポンプと循環水流検出手段を利用した追い焚き熱交換器内の湯水の有無の判断を行わずに、給湯熱交換器の湯を湯張り通路を通して浴槽に落とし込む湯張り制御部と；が設けられている構成をもって前記課題を解決する手段としている。
【００２１】
第４の発明は、給水通路から供給された水を加熱して給湯する給湯熱交換器と、循環ポンプの駆動により追い焚き循環通路を介して供給された浴槽湯水を加熱して浴槽湯水の追い焚きを行う追い焚き熱交換器と、上記循環ポンプの駆動による追い焚き熱交換器の循環水流を検出する循環水流検出手段と、上記給湯熱交換器で作られた湯を浴槽に落とし込むための湯張り通路とが設けられており、上記給湯熱交換器と追い焚き熱交換器は一体化され、これら給湯熱交換器と追い焚き熱交換器を共通に燃焼加熱するバーナとを有し、上記循環ポンプを駆動し循環水流検出手段によって追い焚き熱交換器内の湯水の有無を判断してから給湯熱交換器で作られた湯を湯張り通路を通して浴槽に落とし込む湯張り機能を備えた一缶二水路風呂給湯器において、給湯単独運転が開始されてからの給湯熱交換器の熱効率の変化を監視する熱効率変化監視部と；給湯単独運転の開始直後の時間の経過に対する上記熱効率変化監視部に監視された給湯熱交換器の熱効率の変化の傾きが予め定めたしきい値以下であるときには追い焚き熱交換器内に湯水が有ることを示す水有り信号を出力し水有りフラグを立て、上記熱効率の変化の傾きが上記しきい値よりも大きいときには水無し信号を出力して上記水有りフラグを倒す追い焚き熱交換器湯水有無判断部と；湯張り開始指令が発せられたときに水有りフラグが倒れているときには、循環ポンプと循環水流検出手段を利用した追い焚き熱交換器内の湯水の有無の判断を行わずに、給湯熱交換器の湯を湯張り通路を通して浴槽に落とし込む湯張り制御部と；が設けられている構成をもって前記課題を解決する手段としている。
【００２２】
第５の発明は、上記第４の発明の構成に加えて、浴槽水位を水圧により検出する水位検出手段が給湯熱交換器で作られた湯を追い焚き循環通路を通して浴槽に落とし込む湯張り通路に設けられており、循環水流検出手段が追い焚き循環通路内の水流を検出した以降に、上記水位検出手段により検出される浴槽水位を監視し、追い焚き循環通路内へ空気が混入される可能性がある水位として予め定めた空気混入水位が水位検出手段によって検出されたときに追い焚き熱交換器湯水有無判断部により立てられた水有りフラグを倒す浴槽湯水監視部が設けられている構成をもって前記課題を解決する手段としている。
【００２３】
第６の発明は、上記第１又は第２又は第３又は第４又は第５の発明の構成を備え、しきい値は水無し判断しきい値と該水無し判断しきい値よりも小さい水有り判断しきい値とに別個に設定され、追い焚き熱交換器湯水有無判断部は、給湯単独運転の開始直後の時間の経過に対する熱効率変化監視部に監視された給湯熱交換器の熱効率の変化の傾きが上記水無し判断しきい値よりも大きいときには追い焚き熱交換器内に湯水が無いことを示す水無し信号を出力し、上記熱効率の変化の傾きが上記水有り判断しきい値以下であるときには追い焚き熱交換器内に湯水が有ることを示す水有り信号を出力する構成をもって前記課題を解決する手段としている。
【００２４】
上記構成の発明において、給湯単独運転開始直後における給湯熱交換器の熱効率の変化傾向は追い焚き熱交換器内に湯水が有る場合よりも追い焚き熱交換器内に湯水がない場合の方が大きいという現象に着目し、この発明では、例えば、熱効率変化監視部は、給湯単独運転が開始されてからの給湯熱交換器の熱効率の変化を監視し、追い焚き熱交換器湯水有無判断部は、給湯単独運転の開始直後の時間の経過に対する上記熱効率変化監視部により監視された給湯熱交換器の熱効率の変化の傾きが予め定めたしきい値よりも大きいときには、追い焚き熱交換器に湯水がないことを示す水無し信号を出力し、上記熱効率の傾きが上記しきい値以下であるときには追い焚き熱交換器に湯水が有ることを示す水有り信号を出力する。
【００２５】
上記追い焚き熱交換器湯水有無判断部から水無し信号が出力された後に、湯張り開始指令が発せられたときには、追い焚き熱交換器内に湯水がない状態であると予め判断されていることから、例えば、循環ポンプを駆動させ追い焚き循環通路の循環水流の有無によって追い焚き熱交換器内の湯水の有無を判断するという追い焚き熱交換器湯水有無判断動作を行わずに注湯を開始させる。
【００２６】
このように、湯張り運転を開始するときに、追い焚き熱交換器内に湯水がないと予め検出されているときには、循環ポンプの駆動を行わず、注湯から行うことによって、湯張り開始時の循環ポンプの空運転が回避されて無駄な動作を省略することができ、このような場合には、循環ポンプを駆動させない分、湯張り運転を開始してから設定水位に湯を張り終わるまでに要する時間の短縮が図れる。
【００２７】
【発明の実施の形態】
以下に、この発明に係る実施形態例を図面に基づき説明する。
【００２８】
この実施形態例の一缶二水路風呂給湯器は、前記図３に示すシステム構成を有し、図１にはこの実施形態例において特徴的な制御構成が実線により示されている。図１に示すように、この実施形態例に示す制御装置３５は、給湯単独運転監視部３８と追い焚き熱交換器湯水有無判断部４０と湯張り制御部４１とデータ格納部４２と熱効率変化監視部４３と燃焼熱量制御部４４と熱効率検出部４５を有して構成されている。なお、この実施形態例の説明において、図３のシステム構成の説明は前述したので省略する。
【００２９】
燃焼熱量制御部４４は、入水サーミスタ３０によって検出される入水温度Ｔinと、水量センサ２８によって検出される給湯流量Ｑと、リモコン３６に予め設定されている給湯設定温度Ｔstと、給湯熱交サーミスタ３１によって検出される給湯温度Ｔout とに基づき、給湯される湯の温度が給湯設定温度Ｔstとなるように、バーナ３の燃焼熱量を比例弁８の弁開度でもって制御する。
【００３０】
なお、給湯される湯の温度が給湯設定温度Ｔstとなるためにバーナ３の燃焼熱量を制御する手法には様々な手法が考えられ、ここでは、それらの手法のうちのどの手法を用いてバーナ３の燃焼熱量を制御してもよく、その燃焼熱量制御の説明は省略する。
【００３１】
上記給湯単独運転監視部３８には、循環ポンプ１６の駆動オン信号や、水量センサ２８の通水オン信号や、注湯制御手段２４の開弁信号等の信号が加えられ、それら受け取った信号に基づき、給湯単独運転監視部３８は、給湯単独運転が行われているか否かを監視する。具体的には、例えば、循環ポンプ１６が駆動しておらず、また、注湯制御手段２４が閉弁している状態で、水量センサ２８により通水が検出されているときには給湯単独運転が行われていると検知し、それ以外のときには給湯単独運転は行われていないと検知する。
【００３２】
熱効率検出部４５は、上記燃焼熱量制御部４４の燃焼熱量情報と、上記給湯単独運転監視部３８の監視情報と、入水サーミスタ３０により検出される入水温度Ｔinと、給湯熱交サーミスタ３１により検出される給湯温度Ｔout と、水量センサ２８により検出される給湯流量Ｑとを時々刻々と取り込み、給湯単独運転監視部３８の監視情報に基づき給湯単独運転が開始されたと検知した以降に、上記センサ出力等の情報を取り込む度に、それら取り込んだ情報に基づき給湯熱交換器１０の熱効率ηを次のように検出する。
【００３３】
上記給湯熱交換器１０の熱効率ηを求めるための演算式データは、給湯熱交換器１０に供給される入水温度をＴinと表し、給湯熱交換器１０から流れ出る給湯温度をＴout と表し、給湯熱交換器１０の通水流量をＱと表し、バーナ３の燃焼熱量をＰと表したとき、次式（１）に示すように予め与えられ、この演算式データはデータ格納部４２に予め格納されている。
【００３４】
η＝ｋ・（Ｔout −Ｔin）・Ｑ／Ｐ・・・・・（１）
【００３５】
なお、上記ｋは水の比熱（つまり、ｋ＝１（cal/g・deg））である。
【００３６】
熱効率検出部４５は、給湯熱交換器１０に供給される入水温度Ｔinを入水サーミスタ３０によって検出し、給湯熱交換器１０から流れ出る給湯温度Ｔout を給湯熱交サーミスタ３１によって検出し、給湯熱交換器１０の通水流量Ｑを水量センサ２８によって検出し、バーナ３の燃焼熱量Ｐを燃焼熱量制御部４４の燃焼熱量情報から検出して、給湯単独運転中には、それら検出した情報に基づき上記式（１）に従って、給湯熱交換器１０の熱効率ηを時々刻々と演算検出する。
【００３７】
熱効率変化監視部４３は給湯単独運転監視部３８の情報を取り込み、この監視情報に基づき給湯単独運転が開始されたと検知したときに、熱効率検出部４５により検出された給湯熱交換器１０の熱効率ηの取り込みを開始し、熱効率ηの変化を次のように監視する。例えば、熱効率変化監視部４３はタイマ（図示せず）を内蔵し、給湯熱交換器１０の検出熱効率ηを熱効率検出部４５から取り込み度に、その熱効率ηを時間に対応させてデータ格納部４２に格納する。そして、熱効率変化監視部４３は、給湯単独運転が開始されてから直ぐの時間ｔa （例えば、３秒）を経過したときの給湯熱交換器１０の熱効率ηa に対する時間ｔb （例えば、６秒）のときの給湯熱交換器１０の熱効率ηb の変化の傾きｍ（ｍ＝（ηb −ηa ）／（ｔb −ｔa ）＝Δη／Δｔ）を求めて熱効率ηの変化の傾きｍを監視する。
【００３８】
図２には給湯単独運転が開始されてからの給湯熱交換器１０の熱効率ηの変化例を示すグラフが示されている。同図に示す実線Ａは追い焚き熱交換器１４内に湯水がある場合の熱効率ηの変化を示し、鎖線Ｂは追い焚き熱交換器１４内に湯水がない場合の熱効率ηの変化を示している。上記実線Ａと鎖線Ｂに示されるように、給湯単独運転開始直後における上記給湯熱交換器１０の熱効率ηの変化の傾きｍ（Δη／Δｔ）は、追い焚き熱交換器１４内の湯水の有無によって異なる。
【００３９】
それというのは次のような理由に因る。一缶二水路風呂給湯器では、給湯熱交換器１０と追い焚き熱交換器１４は一体化されていることから、給湯熱交換器１０と追い焚き熱交換器１４間で熱の遣り取りが行われる。給湯単独運転開始時には、追い焚き熱交換器１４内の温度が低いので、バーナ燃焼加熱された給湯熱交換器１０から追い焚き熱交換器１４に吸熱される熱量が多くて給湯熱交換器１０の熱効率ηは低く、上記吸熱によって追い焚き熱交換器１４内の温度が高くなるに従って給湯熱交換器１０から追い焚き熱交換器１４への吸熱熱量が減少していき、図２の実線Ａや鎖線Ｂに示すように、給湯熱交換器１０の熱効率ηは上昇するが、空気の比熱は水の比熱よりも小さく、空気の重量は該空気の体積と同じ体積の水の重量よりも格段に軽いので、追い焚き熱交換器１４内の温度は、内部が水である場合よりも空気である場合の方が早く上昇することとなり、このことに起因して、追い焚き熱交換器１４内に湯水がなく空気である場合は追い焚き熱交換器１４内に湯水がある場合よりも給湯熱交換器１０の熱効率ηの上昇傾きｍが大幅に大きくなる。
【００４０】
上記のように、給湯単独運転開始直後における上記給湯熱交換器１０の熱効率ηの変化の傾きｍ（Δη／Δｔ）は、追い焚き熱交換器１４内の湯水の有無によって異なることから、給湯単独運転開始直後における給湯熱交換器１０の熱効率ηの変化の傾きｍの大小によって追い焚き熱交換器１４内の湯水の有無を判断することが可能である。
【００４１】
なお、図２の実線Ａや鎖線Ｂに示すように、給湯単独運転が開始された直後には給湯熱交換器１０の熱効率ηは上昇するが、追い焚き熱交換器１４内の温度が例えば８０〜９０℃程度に上昇して温度上昇が殆どなくなると、給湯熱交換器１０の熱効率ηは追い焚き熱交換器１４の湯水の有無に関係ない一定の値で殆ど変化しなくなるので、給湯熱交換器１０の熱効率の変化を利用して追い焚き熱交換器１４内の湯水の有無を判断するためには、追い焚き熱交換器１４内の湯水の有無によって大きな違いが現われる給湯単独運転直後の給湯熱交換器１０の熱効率の変化の傾きを利用する。
【００４２】
データ格納部４２には、追い焚き熱交換器１４内に湯水が有るか否かを判断するためのしきい値としての給湯熱交換器１０の熱効率ηの変化の傾きが実験や演算等によって予め求めて格納されている。
【００４３】
追い焚き熱交換器湯水有無判断部４０は給湯単独運転監視部３８の情報を取り込み、この監視情報に基づき給湯単独運転が開始されたと検知したときには、前記熱効率変化監視部４３により求められた給湯熱交換器１０の熱効率ηの変化の傾きｍを取り込み、この熱効率ηの変化の傾きｍを上記データ格納部４２のしきい値に比較し、上記傾きｍがしきい値よりも大きいときには、追い焚き熱交換器１４内は空気である、つまり、追い焚き熱交換器１４内に湯水がないと判断して、水無し信号を出力し、追い焚き熱交換器１４内に湯水がないことを示す水無しフラグをデータ格納部４２に立てる。
【００４４】
また、追い焚き熱交換器湯水有無判断部４０は、上記傾きｍがしきい値以下であったときには、追い焚き熱交換器１４内に湯水が有ると判断して追い焚き熱交換器１４内に湯水が有ることを示す水有り信号を出力し、データ格納部４２に水無しフラグが立っているときには水無しフラグを倒す。
【００４５】
湯張り制御部４１は、リモコン３６の湯張り開始ボタンが押される等して湯張り開始指令が発せられたことを検知したときには、データ格納部４２に水無しフラグが立っているか否かを判断し、データ格納部４２に水無しフラグが立っていると判断したときには、追い焚き熱交換器１４内に湯水がないと判断し、このときには、前述したような循環ポンプ１６と水流スイッチ３４を利用した追い焚き熱交換器１４内の湯水の有無判断動作を省略し、つまり、前記図４のステップ１０１，１０２の動作を省略して、ステップ１０３の動作（注湯動作）から湯張りを開始させる。
【００４６】
それ以外のときは、つまり、データ格納部４２に水無しフラグが立っていないときには、湯張り制御部４１は、前述したように、図４のステップ１０１，１０２の動作を行って追い焚き熱交換器１４内に湯水が有ることを確認してから、次の湯張り運転動作に移行する。それというのは、上記の如く、追い焚き熱交換器湯水有無判断部４０によって追い焚き熱交換器１４内に湯水が有ると判断されてから湯張り運転が開始されるまでの間に、浴槽１７の湯水が排水される虞があるので、追い焚き熱交換器湯水有無判断部４０によって追い焚き熱交換器１４内に湯水が有ると判断されていても、確認のため、追い焚き熱交換器１４内の湯水の有無、つまり、浴槽１７の湯水の有無を判断してから、次の湯張り運転動作に移行するようにする。
【００４７】
この実施形態例によれば、給湯単独運転開始直後における給湯熱交換器１０の熱効率ηの変化の傾きｍに基づいて追い焚き熱交換器１４内の湯水の有無を判断する追い焚き熱交換器湯水有無判断部４０を設けたので、湯張りを開始する前に追い焚き熱交換器１４内の湯水の有無を予め検出しておくことが可能となる。
【００４８】
また、追い焚き熱交換器１４内に湯水がないと検出されているときに、湯張りを開始するときには、循環ポンプ１６の駆動を行わずに注湯から湯張りを開始する湯張り制御部４１を設けたので、追い焚き熱交換器１４内に湯水がない湯張りの開始時には循環ポンプ１６の駆動が行われないこととなり、追い焚き熱交換器１４内の湯水がないのに循環ポンプ１６の空運転が行われるという無駄を省くことができる上に、湯張り開始時の循環ポンプ１６の駆動時間を省くことができるので、その分、湯張り運転を開始してから浴槽に設定水位の湯を張り終わるまでに要する時間を短くすることができる。
【００４９】
また、湯張り開始時の循環ポンプ１６の空運転が回避されるので、循環ポンプ１６の空運転の回数を激減させることができ、空運転が度重なることによる循環ポンプ１６の故障発生を防止することが可能となる。
【００５０】
なお、この発明は上記実施形態例に限定されるものではなく、様々な実施の形態を採り得る。例えば、上記実施形態例では、追い焚き熱交換器１４内の湯水の有無を判断するためのしきい値は１個であったが、追い焚き熱交換器１４内の水有り状態を判断するための水有り判断しきい値と、追い焚き熱交換器１４内の水無し状態を判断するための上記水有り判断しきい値よりも大きい水無し判断しきい値とを別個に設けてもよい。
【００５１】
このような場合には、追い焚き熱交換器湯水有無判断部４０は、熱効率変化監視部４３により検出された給湯熱交換器１０の熱効率ηの変化の傾きｍを上記水無し判断しきい値、水有り判断しきい値にそれぞれ比較し、上記傾きｍが水無し判断しきい値よりも大きいときには、追い焚き熱交換器１４内に湯水がないと判断し、水無し信号を出力し、上記傾きｍが水有り判断しきい値以下であるときには、追い焚き熱交換器１４内に湯水があると判断し、水有り信号を出力する。湯張り制御部４１は、上記追い焚き熱交換器湯水有無判断部４０によって水無し信号が出力された後に湯張りを行うときには、上記実施形態例と同様に、循環ポンプ１６と水流スイッチ３４を用いた追い焚き熱交換器１４内の湯水の有無判断を行わずに注湯動作から湯張り運転を開始する。
【００５２】
さらに、上記実施形態例では、湯張り運転は図４に示すフローチャートに従って行われたが、循環ポンプ１６と水流スイッチ３４を用いて追い焚き熱交換器１４内の湯水の有無判断を行ってから注湯を行う湯張り動作であれば、図４に示すフローチャートの動作に限定されるものではない。
【００５３】
さらに、上記実施形態例では、熱効率検出部４５は、燃焼熱量Ｐの情報を燃焼熱量制御部４４から取り込んでいたが、比例弁８の弁開度を検出し、つまり、比例弁駆動電流を検出し燃焼熱量Ｐの情報として取り込んでもよい。
【００５４】
さらに、上記実施形態例では、熱効率変化監視部４３は、予め定めた時間ｔa のときの給湯熱交換器１０の熱効率ηa に対する時間ｔb のときの給湯熱交換器１０の熱効率ηb の変化の傾きｍを求めて給湯熱交換器１０の熱効率ηの変化を監視していたが、例えば、予め定めた時間間隔（例えば、０．１秒間隔）毎に給湯熱交換器１０の熱効率ηの変化の傾きを求め、予め定めた時間（例えば、１０秒間）分の上記求めた熱効率ηの変化の傾きの平均を求めて給湯単独運転開始直後の給湯熱交換器１０の熱効率ηの変化の傾きｍとして熱効率ηの変化の傾きを監視してもよい。
【００５５】
さらに、上記実施形態例では、追い焚き熱交換器湯水有無判断部４０は追い焚き熱交換器１４内に湯水が無いと判断したときには水無し信号を出力して水無しフラグを立て、追い焚き熱交換器１４内に湯水が有ると判断したときには水有り信号を出力して上記水無しフラグを倒していたが、追い焚き熱交換器湯水有無判断部４０は追い焚き熱交換器１４内に湯水が有ると判断したときには水有り信号を出力して水有りフラグを立て、追い焚き熱交換器１４内に湯水が無いと判断したときには水無し信号を出力し上記水有りフラグが立っているときにはその水有りフラグを倒すようにしてもよく、この場合には、湯張り制御部４１は、湯張り開始指令が発せられたときに水有りフラグが立っていないときには、追い焚き熱交換器１４内に湯水が無いと判断して、上記実施形態例同様に、循環ポンプ１６と水流スイッチ３４を利用した追い焚き熱交換器１４内の湯水の有無判断動作を省略して注湯動作から湯張りを開始する。
【００５６】
ところで、水有りフラグが立っている状態で浴槽水が大量に使用されたり排水されて浴槽６の水位が循環金具１９よりも低くなり追い焚き循環通路２１に空気が入り込んでしまい、水有りフラグが立っているのに追い焚き熱交換器１４内に湯水が無いという事態が発生してしまう虞があるので、その事態発生を防止するために、図１の点線に示す浴槽湯水監視部４６を設けることが望ましい。
【００５７】
上記浴槽湯水監視部４６は、追い焚き運転や湯張り運転による循環ポンプ１６の駆動によって水流スイッチ３４により追い焚き循環通路２１の循環水流が検出された以降に、水位センサ３２により検出される浴槽水位を時々刻々と取り込んで浴槽水位を監視し、予め定めた空気混入水位（例えば、循環金具１９の上端よりも低い水位）が水位センサ３２により検出されたときには、追い焚き循環通路２１内にエアーが入り込んでいる虞があると判断し、追い焚き熱交換器湯水有無判断部４０により立てられた水有りフラグを倒す構成を有している。
【００５８】
上記浴槽湯水監視部４６を設けることで、該浴槽湯水監視部４６によって、浴槽水位が循環金具１９よりも低下し追い焚き熱交換器１４内に湯水が無くなったときには水有りフラグが倒されるので、追い焚き熱交換器内の湯水の有無の状態と水有りフラグの状態とをほぼ一致させることができ、追い焚き熱交換器１４内に湯水が無いのに水有りフラグが立っているという事態発生をほぼ回避することができる。
【００５９】
なお、湯張り運転等によって循環金具１９よりも上側の水位に湯水が張られた後に浴槽湯水が使用されたり排水されて浴槽水位が循環金具１９よりも低下すると追い焚き循環通路２１内にはエアーが入り込むことから、循環金具１９以下の水位が水位センサ３２により検出された以降には、上記追い焚き循環通路２１内のエアーに起因して水位センサ３２は精度良く浴槽水位を検出することができないという問題があるので、湯張り運転等によって循環金具１９よりも上側の水位に湯水が張られた後に循環金具１９以下の水位が水位センサ３２により検出された以降には、水位センサ３２により循環金具１９よりも上側の水位が検出されても、浴槽水位が循環金具１９よりも上側で追い焚き熱交換器１４内に湯水が入り込んだと判断することはできない。
【００６０】
上記の如く追い焚き循環通路２１内にエアーが入り込んでも、湯張り運転による湯張り水流や、追い焚き運転による循環ポンプ１６の循環水流によって追い焚き循環通路２１内のエアーは浴槽６に押し出されるので、湯張り運転や追い焚き運転によって水流センサ３４により追い焚き循環通路２１内の水流を検出した以降には水位センサ３２は再び精度良く浴槽水位を検出することができる。
【００６１】
【発明の効果】
この発明によれば、給湯単独運転開始直後の時間の経過に対する給湯熱交換器の熱効率の変化の傾きに基づき追い焚き熱交換器内の湯水の有無を判断する追い焚き熱交換器湯水有無判断部を設けたので、給湯単独運転を行いながら、追い焚き熱交換器内の湯水の有無を簡単に判断することができ、従来では、例えば、湯張り開始時に、循環ポンプを駆動して該循環ポンプの駆動による追い焚き循環通路の循環水流の有無によって追い焚き熱交換器内の湯水の有無を判断するという動作を行っていたが、この発明では、湯張りが開始される前の給湯単独運転時に、上記の如く、追い焚き熱交換器内の湯水の有無を予め検出しておくことが可能である。
【００６２】
追い焚き熱交換器湯水有無判断部によって水無し信号が出力された後に湯張りを行うとき、又は、追い焚き熱交換器湯水有無判断部により水無し信号が出力され水無しフラグが立てられているとき、又は、追い焚き熱交換器湯水有無判断部により水無し信号が出力され水有りフラグが倒されているときには、循環ポンプの駆動による追い焚き循環通路の循環水流の有無によって追い焚き熱交換器内の湯水の有無を判断する動作を行わずに、湯を浴槽に落とし込む湯張り制御部を備えたものにあっては、湯張り開始時に追い焚き熱交換器内に湯水がないのにも拘らず循環ポンプが駆動される空運転が回避され、空運転による無駄な動作を省くことができる。また、循環ポンプの空運転の回数が格段に減少し、空運転が度重なることによる循環ポンプの故障等の問題発生の確率を大幅に低くすることができる。
【００６３】
さらに、湯張り開始時に、湯張り制御部によって、循環ポンプを用いた追い焚き熱交換器内の湯水の有無判断動作が省略されたときには、その湯水有無判断動作を省略した分、湯張りに要する時間の短縮を図ることができる。
【００６４】
浴槽湯水監視部を設けた構成を備えたものにあっては、予め定めた空気混入水位が水位検出手段により検出されたときに追い焚き熱交換器湯水有無判断部により立てられた水有りフラグを浴槽湯水監視部によって倒すので、浴槽水位が低下して追い焚き熱交換器内から湯水が抜け出て追い焚き熱交換器内に湯水が無いのに水有りフラグが立っているという事態を回避することができる。
【００６５】
水無し判断しきい値と水有り判断しきい値とを別個に設けたものにあっては、上記同様に、追い焚き熱交換器内の湯水の有無を判断できるはもちろんのこと、追い焚き熱交換器内に水と空気が混在しているような場合をも判断することが可能となる。
【図面の簡単な説明】
【図１】この発明に係る実施形態例において特徴的な制御構成を示すブロック図である。
【図２】給湯単独運転時の給湯熱交換器の熱効率ηの変化例を示すグラフである。
【図３】一缶二水路風呂給湯器のモデル例を示す説明図である。
【図４】湯張り運転動作の一例を示すフローチャートである。
【符号の説明】
３ バーナ
１０ 給湯熱交換器
１４ 追い焚き熱交換器
１６ 循環ポンプ
２１ 追い焚き循環通路
３４ 水流スイッチ
４０ 追い焚き熱交換器湯水有無判断部
４１ 湯張り制御部
４３ 熱効率変化監視部
４６ 浴槽湯水監視部[0001]
BACKGROUND OF THE INVENTION
The present invention is a one-can two-water channel type in which a hot water supply heat exchanger and a reheating heat exchanger are integrated, and a burner is provided for combustion heating the hot water supply heat exchanger and the reheating heat exchanger in common. It relates to bath water heaters.
[0002]
[Prior art]
In FIG. 3, a model example of a single can / two water bath hot water heater (apparatus) is shown by a solid line. This instrument has a combustion chamber 2 in an instrument case 1, and a burner 3 is provided in the combustion chamber 2. A gas supply passage 4 for introducing fuel gas to the burner 3 is connected to the burner 3. The gas supply passage 4 has electromagnetic valves 5 and 6 for opening and closing the passage, and the amount of fuel gas supplied depending on the valve opening degree. And a proportional valve 8 for controlling.
[0003]
A hot water supply heat exchanger 10 is provided above the burner 3. One end side of the water supply passage 11 is connected to the inlet side of the hot water supply heat exchanger 10, and the other end side of the water supply passage 11 is connected to water via an external pipe. Connected to the supply source. One end side of the hot water supply passage 12 is connected to the outlet side of the hot water supply heat exchanger 10, and the other end side of the hot water supply passage 12 is communicated with a hot water supply place such as a kitchen or a shower through an external pipe.
[0004]
A reheating heat exchanger 14 is provided integrally with the hot water heat exchanger 10 on the upper side of the hot water heat exchanger 10, and one end side of the passage 15 is connected to the inlet side of the reheating heat exchanger 14. The other end side of the passage 15 is connected to the discharge port of the circulation pump 16, and one end side of the return pipe 18 is connected to the suction port of the circulation pump 16, and the other end side of the return pipe 18 is connected to external piping and a circulation fitting 19. The one end side of the outgoing pipe 20 is connected to the outlet side of the reheating heat exchanger 14, and the other end side of the outgoing pipe 20 is connected to the bathtub 17 via the external pipe and the circulation fitting 19. It is communicated to. The return pipe 18, the circulation pump 16, the passage 15, the reheating heat exchanger 14, and the outgoing pipe 20 constitute a recirculation circulation passage 21 for replenishing and circulating the hot water in the bathtub 17.
[0005]
A pouring passage 22 for connecting the hot water supply passage 12 and the passage 15 of the recirculation circulation passage 21 is provided, and the pouring control means constituted by an electromagnetic valve or the like for opening and closing the passage. 24 is interposed. The hot water supply passage 12, the pouring passage 22 and the recirculation circulation passage 21 constitute a hot water filling passage through which hot water produced by the hot water supply heat exchanger 10 is dropped into the bathtub 17.
[0006]
An air supply passage 26 in which a combustion fan 25 is interposed is connected to the combustion chamber 2 below the burner 3. Further, an exhaust passage 27 for communicating exhaust gas generated by the combustion of the burner 3 to the outside is connected to the combustion chamber 2 above the reheating heat exchanger 14.
[0007]
3 represents a water amount sensor for detecting the flow rate of water flowing through the water supply passage 11, 30 represents an incoming thermistor for detecting the hot water temperature in the water supply passage 11, and 31 represents hot water flowing out of the hot water supply heat exchanger 10. A hot water supply heat exchange thermistor that detects the temperature, 32 indicates a water level sensor that detects the water level of the bathtub by water pressure, 33 indicates a bath temperature sensor that detects the hot water temperature of the recirculation circulation passage 21 as a bath temperature, and 34 indicates a follow-up temperature sensor. The water flow switch which is a circulating water flow detection means for detecting the water flow of the circulating circulation passage 21 as the water flow of the heat exchanger 14 is shown.
[0008]
This one-can two-water bath water heater is provided with a control device 35 for controlling the operation of appliances such as hot water supply, hot water filling, chasing, and heat insulation, and a remote control 36 is connected to the control device 35 as a signal. . The remote controller 36 is provided with hot water supply temperature setting means for setting the hot water supply temperature, bath temperature setting means for setting the bath temperature, water level setting means for setting the bath water level, and the like.
[0009]
The control device 35 controls the hot water supply operation as follows. For example, when a hot water tap (not shown) such as a kitchen or a shower is opened and the water amount sensor 28 detects a water flow rate that is equal to or higher than a predetermined hot water supply operation flow rate, the combustion fan 25 starts to be driven and the air supply passage In addition to supplying air supply to the burner 3 via 26, the solenoid valves 5 and 6 are opened to supply fuel gas to the burner 3, combustion of the burner 3 is started, and the temperature of hot water to be supplied is set in the remote controller 36. The combustion heat amount control of the burner 3 and the rotation control of the combustion fan 25 are controlled so that the set hot water supply temperature is reached, and the hot water supply heat exchanger 10 heats the water supplied from the water supply passage 11 by the heat of the combustion flame of the burner 3. Then, hot water is produced, and the hot water is supplied through the hot water supply passage 12. When the hot water tap is closed and the water amount sensor 28 detects the stoppage of water flow, the solenoid valves 5 and 6 are closed to stop the combustion of the burner 3, and then the combustion fan 25 is continued for a predetermined period. Drive to prepare for the next hot water supply operation.
[0010]
When performing the hot water filling operation, for example, as shown in the flowchart of FIG. 4, first, the circulation pump 16 is driven for a predetermined period (for example, 1 minute) (step 101), and the circulation pump 16 is driven. It is determined whether or not the circulating water flow in the recirculation circulation passage 21 has been detected by the water flow switch 34 (step 102). When there is no hot water in the bathtub 17 or the water level of the bathtub 17 is lower than the circulating metal fitting 19, there is no hot water in the recirculation circulation passage 21, and even if the circulation pump 16 is driven, the recirculation is recirculated. Since hot water cannot be drawn into the passage 21 and hot water does not circulate in the recirculation circulation passage 21, when the water flow switch 34 detects no circulating water flow in the recirculation circulation passage 21, Or the water level of the bathtub 17 is lower than that of the circulation fitting 19, the water injection control means 24 is opened, hot water is produced in the hot water supply heat exchanger 10 in the same manner as the hot water supply operation, and the hot water is supplied to the hot water supply passage 12. The hot water filling passage 22 and the recirculation circulation passage 21 are poured into the bathtub 17 in order, and the amount of hot water pouring from the start of the hot water filling detected based on the pouring flow rate detected by the water amount sensor 28 is determined in advance. It was x l (e.g., 10 L) to close the pouring control means 24 when it reaches the (step 103).
[0011]
Then, similarly to the above, the circulating pump 16 is driven (step 104), it is determined whether or not the circulating water flow by the circulating pump 16 is detected by the water flow switch 34 (step 105), and the circulating water flow is detected by the water flow switch 34. If not, a predetermined y liter (for example, 10 liters) is poured (step 106), the circulation pump 16 is driven again (step 107), the presence or absence of the circulating water flow is determined (step 108), and the water flow switch When no circulating water flow is detected by 34, a predetermined z liter (for example, 5 liters) is poured (step 109).
[0012]
Furthermore, the circulating pump 16 is driven (step 110), the presence or absence of the circulating water flow is determined (step 111), and when the circulating water flow is not detected, it is determined that the water level of the bathtub 17 is lower than the circulating metal fitting 19, The water level of the bathtub 17 is higher than the circulating metal fitting 19 even though a sufficient amount of pouring water has been dropped into the bathtub 17 from the start of filling, so that the water level of the bathtub 17 is higher than the circulating metal fitting 19. It is determined that it is not abnormal, and an error signal is output (step 116).
[0013]
When the circulating water flow is detected by the water flow switch 34 during the operation for determining the presence or absence of the circulating water flow (steps 102, 105, 108, 111), the water level of the bathtub 17 is above the circulating metal fitting 19 and the water level sensor 32 detects the water level. The water level sensor 32 detects the bath water level (step 112), and determines whether the detected bath water level is a bath water level preset in the remote control 36 (step 112). 113). When it is determined that the bathtub water level has not reached the bathtub set water level, the hot water of the hot water supply heat exchanger 10 is poured into the bathtub 17 in the same manner as described above, and the bathtub water level is monitored by the water level sensor 32 (step 114). When it is determined that the water level has been reached, the pouring control means 24 is closed and the hot water filling operation is terminated (step 115).
[0014]
Further, when the reheating operation is performed, the circulation pump 16 is driven, and the recirculation is returned from the bathtub 17 to the bathtub 17 through the return pipe 18, the circulation pump 16, the passage 15, the reheating heat exchanger 14, and the outgoing pipe 20 in order. Bath water is circulated through the water circulation path, the burner 3 is combusted, the heat of the combustion flame of the burner 3 is reheated, the hot water in the bathtub is reheated, and the bath temperature detected by the bath temperature sensor 33 is detected. When the temperature reaches the bath set temperature set in the remote controller 36, the combustion of the burner 3 is stopped, and the circulation pump 16 is stopped to end the reheating operation.
[0015]
Further, when performing the heat insulation operation, for example, after the reheating operation is finished, the circulation pump 16 is driven every predetermined time interval (for example, every 30 minutes), and the bath temperature sensor 33 is used to adjust the bath temperature. When the detected bath temperature is lower than the preset allowable temperature from the bath set temperature, the burner 3 is burned and the bath water is reheated to raise the bath temperature to the set temperature. Keep warm.
[0016]
[Problems to be solved by the invention]
By the way, when the hot water filling operation is performed, as described above, first, the circulating pump 16 is driven, and hot water is supplied into the reheating heat exchanger 14 depending on the presence or absence of the circulating water flow in the recirculation circulation passage 21 by the driving of the circulation pump 16. After determining whether or not there is (steps 101 and 102 shown in FIG. 4), pouring was started. Thus, conventionally, if the circulation pump 16 is not driven at the start of hot water filling, the presence or absence of hot water in the recirculation circulation passage 21 (refreshing heat exchanger 14) (that is, the water level of the bathtub 17 is higher than that of the circulation fitting 19). Therefore, the circulation pump 16 must be driven even when there is no hot water in the recirculation passage 21 at the start of hot water filling. In such a case, the circulation pump 16 is empty. The operation becomes a wasteful operation, and when such idle operation is repeated, there arises a problem that the circulation pump 16 is likely to fail.
[0017]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a single can two-way water heater that can detect in advance the presence or absence of hot water in a reheating heat exchanger. It is in.
[0018]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has the following configuration as means for solving the above-mentioned problems. That is, the first invention heats the water supplied from the water supply passage and supplies hot water, and heats the bathtub hot water supplied through the recirculation circulation passage to retreat the bathtub hot water. A reheating heat exchanger is provided, the hot water supply heat exchanger and the reheating heat exchanger are integrated, and the hot water supply heat exchanger and the reheating heat exchanger are provided with a burner that commonly burns and heats the reheating heat exchanger. A thermal efficiency change monitoring unit for monitoring a change in thermal efficiency of a hot water supply heat exchanger after a hot water supply single operation is started in a single can two-way water heater; and the above thermal efficiency change monitoring with respect to the passage of time immediately after the start of the single hot water supply operation When the slope of the change in the thermal efficiency of the hot water supply heat exchanger monitored in the section is larger than a predetermined threshold value, a waterless signal indicating that there is no hot water in the reheating heat exchanger is output, and the change in the thermal efficiency The inclination of As a means for solving the above-mentioned problem, there is provided a reheating heat exchanger hot / cold water presence / absence determining unit that outputs a water presence signal indicating that hot water is present in the reheating heat exchanger when the temperature is less than the threshold value. Yes.
[0019]
According to a second aspect of the present invention, a hot water supply heat exchanger that heats and supplies hot water supplied from a water supply passage, and a bathtub hot water supplied through the circulation passage by driving a circulation pump to heat the bathtub hot water. A reheating heat exchanger for performing watering, a circulating water flow detecting means for detecting a circulating water flow of the reheating heat exchanger driven by the circulation pump, and hot water for dropping the hot water produced by the hot water supply heat exchanger into the bathtub The hot water supply heat exchanger and the reheating heat exchanger are integrated, and the hot water supply heat exchanger and the reheating heat exchanger have a burner for combusting and heating in common. One can two equipped with a hot water filling function that drops the hot water made by the hot water supply heat exchanger into the bathtub through the hot water filling passage after the pump is driven and the presence or absence of hot water in the heat exchanger is judged by the circulating water flow detection means To water bath hot water heater A thermal efficiency change monitoring unit that monitors a change in the thermal efficiency of the hot water heat exchanger after the hot water single operation is started; and the hot water heat monitored by the thermal efficiency change monitoring unit with respect to the elapse of time immediately after the start of the hot water single operation When the slope of the change in the heat efficiency of the exchanger is greater than a predetermined threshold value, a no water signal is output indicating that there is no hot water in the reheating heat exchanger, and the slope of the change in the heat efficiency is below the threshold value. A reheating heat exchanger hot / cold water presence / absence determination unit that outputs a water presence signal indicating that hot water is present in the reheating heat exchanger; and a hot water filling start command is issued after the absence of water signal is output. Sometimes, a hot water control unit that drops hot water of the hot water heat exchanger into the bathtub through the hot water passage without judging whether or not there is hot water in the reheating heat exchanger using the circulating pump and the circulating water flow detection means; Setting With a configuration that is it has a means for solving the problems.
[0020]
According to a third aspect of the present invention, there is provided a hot water supply heat exchanger that heats and supplies hot water supplied from a water supply passage and a hot water supplied from the hot water supplied through the circulation passage by driving a circulation pump. A reheating heat exchanger for performing watering, a circulating water flow detecting means for detecting a circulating water flow of the reheating heat exchanger driven by the circulation pump, and hot water for dropping the hot water produced by the hot water supply heat exchanger into the bathtub The hot water supply heat exchanger and the reheating heat exchanger are integrated, and the hot water supply heat exchanger and the reheating heat exchanger have a burner for combusting and heating in common. One can two equipped with a hot water filling function that drops the hot water made by the hot water supply heat exchanger into the bathtub through the hot water filling passage after the pump is driven and the presence or absence of hot water in the heat exchanger is judged by the circulating water flow detection means To water bath hot water heater A thermal efficiency change monitoring unit that monitors a change in the thermal efficiency of the hot water heat exchanger after the hot water single operation is started; and the hot water heat monitored by the thermal efficiency change monitoring unit with respect to the elapse of time immediately after the start of the hot water single operation When the slope of the change in the heat efficiency of the exchanger is larger than a predetermined threshold value, a waterless signal indicating that there is no hot water in the reheating heat exchanger is output, a waterless flag is set, and the slope of the change in thermal efficiency is When the temperature is below the threshold value, a water presence signal indicating that there is hot water in the reheating heat exchanger is output, and the reheating heat exchanger hot water presence / absence judgment unit which defeats the non-water flag; When the no water flag is set, the hot water supply heat exchanger is filled with hot water without judging whether there is hot water in the reheating heat exchanger using the circulation pump and the circulating water flow detection means. Through Hot water filling control unit dropped bathtub and; is a means of solving the problem with a configuration provided.
[0021]
According to a fourth aspect of the present invention, there is provided a hot water supply heat exchanger that heats and supplies hot water supplied from a water supply passage, and a bathtub hot water supplied through the circulation passage by driving a circulation pump to follow the hot water in the bathtub. A reheating heat exchanger for performing watering, a circulating water flow detecting means for detecting a circulating water flow of the reheating heat exchanger driven by the circulation pump, and hot water for dropping the hot water produced by the hot water supply heat exchanger into the bathtub The hot water supply heat exchanger and the reheating heat exchanger are integrated, and the hot water supply heat exchanger and the reheating heat exchanger have a burner for combusting and heating in common. One can two equipped with a hot water filling function that drops the hot water made by the hot water supply heat exchanger into the bathtub through the hot water filling passage after the pump is driven and the presence or absence of hot water in the heat exchanger is judged by the circulating water flow detection means To water bath hot water heater A thermal efficiency change monitoring unit that monitors a change in the thermal efficiency of the hot water heat exchanger after the hot water single operation is started; and the hot water heat monitored by the thermal efficiency change monitoring unit with respect to the elapse of time immediately after the start of the hot water single operation When the slope of the change in the heat efficiency of the exchanger is below a predetermined threshold, a water presence signal indicating that there is hot water in the reheating heat exchanger is output and a water presence flag is set, and the slope of the change in the thermal efficiency is A reheating heat exchanger hot / cold water presence / absence judgment unit that outputs a water-free signal and defeats the water-present flag when the water pressure is greater than the threshold value; and a water-present flag is defeated when a hot water start command is issued A hot water filling control unit that drops hot water in the hot water heat exchanger into the bathtub through the hot water filling passage without determining whether hot water in the reheating heat exchanger using the circulation pump and the circulating water flow detection means is present; With a configuration provided is a means to solve the problem.
[0022]
In a fifth aspect of the present invention, in addition to the configuration of the fourth aspect of the present invention, a water level detecting means for detecting the bathtub water level by water pressure replenishes hot water produced by the hot water supply heat exchanger and drops it into the bathtub through the circulation passage. There is a possibility that after the circulating water flow detection means detects the water flow in the recirculation circulation passage, the bath water level detected by the water level detection means is monitored, and air may be mixed into the recirculation circulation passage. And a bath hot / cold water monitoring section for defeating a water presence flag set by a reheating heat exchanger hot / cold water presence / absence determination section when a water level detection means previously detected as a certain water level is detected by the water level detection means. As a means to solve the problem.
[0023]
A sixth aspect of the invention comprises the configuration of the first, second, third, fourth or fifth aspect of the invention, wherein the threshold value is a water absence judgment threshold value and water smaller than the water absence judgment threshold value. Set separately to the presence threshold, the reheating heat exchanger hot water presence / absence determination unit changes the thermal efficiency of the hot water heat exchanger monitored by the thermal efficiency change monitoring unit over time immediately after the start of hot water single operation When the slope of the water is larger than the threshold value for determining whether there is no water, a waterless signal indicating that there is no hot water in the reheating heat exchanger is output, and the slope of the change in thermal efficiency is less than the threshold value for determining whether there is water. In some cases, a means for solving the above-described problem is configured to output a water presence signal indicating that hot water is present in the reheating heat exchanger.
[0024]
In the invention of the above configuration, the tendency of change in the thermal efficiency of the hot water heat exchanger immediately after the start of hot water single operation is greater when there is no hot water in the reheating heat exchanger than when there is hot water in the reheating heat exchanger. In this invention, for example, the thermal efficiency change monitoring unit monitors the change in the thermal efficiency of the hot water supply heat exchanger after the hot water supply single operation is started, and the reheating heat exchanger hot water presence / absence determination unit is, When the slope of the change in the thermal efficiency of the hot water heat exchanger monitored by the thermal efficiency change monitoring unit with respect to the passage of time immediately after the start of the hot water supply individual operation is greater than a predetermined threshold value, hot water is not supplied to the reheating heat exchanger. A no-water signal indicating that there is no water is output, and when the slope of the thermal efficiency is equal to or less than the threshold value, a water-present signal indicating that hot water is present in the reheating heat exchanger is output.
[0025]
When a hot water start command is issued after a water-free signal is output from the reheating heat exchanger hot / cold water presence / absence determination unit, it is determined in advance that there is no hot water in the reheating heat exchanger. From, for example, start pouring without using the reheating heat exchanger hot water presence / absence judgment operation of driving the circulation pump and judging the presence or absence of hot water in the reheating heat exchanger based on the presence or absence of the circulating water flow in the recirculation circulation passage Let
[0026]
As described above, when it is detected in advance that there is no hot water in the reheating heat exchanger when the hot water filling operation is started, the circulation pump is not driven, and the hot water filling is started by pouring from the hot water. Since the idle operation of the circulating pump is avoided, unnecessary operation can be omitted. In such a case, the hot water filling operation is started until the hot water is filled to the set water level by the amount that the circulating pump is not driven. Can be shortened.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments according to the present invention will be described below with reference to the drawings.
[0028]
The single can two-way bath water heater in this embodiment has the system configuration shown in FIG. 3, and FIG. 1 shows a characteristic control configuration in this embodiment by a solid line. As shown in FIG. 1, the control device 35 shown in this embodiment includes a hot water supply single operation monitoring unit 38, a reheating heat exchanger hot / cold water presence / absence determination unit 40, a hot water control unit 41, a data storage unit 42, and a thermal efficiency change monitor. It comprises the part 43, the combustion heat quantity control part 44, and the thermal efficiency detection part 45. In the description of this embodiment, the description of the system configuration in FIG.
[0029]
The combustion heat quantity control unit 44 includes a incoming water temperature Tin detected by the incoming water thermistor 30, a hot water supply flow rate Q detected by the water quantity sensor 28, a hot water supply set temperature Tst preset in the remote controller 36, and a hot water supply heat exchange thermistor 31. Is controlled by the valve opening of the proportional valve 8 so that the temperature of the hot water to be supplied becomes the hot water set temperature Tst.
[0030]
In addition, since the temperature of the hot water to be supplied becomes the hot water supply set temperature Tst, there are various methods for controlling the combustion heat amount of the burner 3, and here, any of these methods is used to burn the burner. The combustion heat quantity 3 may be controlled, and the description of the combustion heat quantity control is omitted.
[0031]
The hot water supply single operation monitoring unit 38 is added with signals such as a drive-on signal for the circulation pump 16, a water flow-on signal for the water amount sensor 28, a valve opening signal for the pouring control means 24, and the like. Based on this, the hot water supply single operation monitoring unit 38 monitors whether or not the hot water supply single operation is performed. Specifically, for example, when the circulating pump 16 is not driven, and the pouring control means 24 is closed, when water flow is detected by the water amount sensor 28, the hot water supply single operation is performed. It is detected that the hot water supply is not operating otherwise.
[0032]
The thermal efficiency detection unit 45 is detected by the combustion heat amount information of the combustion heat amount control unit 44, the monitoring information of the hot water supply single operation monitoring unit 38, the incoming water temperature Tin detected by the incoming water thermistor 30, and the hot water supply heat exchange thermistor 31. After the hot water supply temperature Tout and the hot water supply flow rate Q detected by the water amount sensor 28 are taken in every moment and it is detected that the single hot water supply operation is started based on the monitoring information of the single hot water supply operation monitoring unit 38, the sensor output, etc. Each time the information is captured, the thermal efficiency η of the hot water supply heat exchanger 10 is detected as follows based on the retrieved information.
[0033]
The calculation formula data for obtaining the thermal efficiency η of the hot water supply heat exchanger 10 represents the temperature of the incoming water supplied to the hot water supply heat exchanger 10 as Tin, and the temperature of the hot water flowing out of the hot water supply heat exchanger 10 as Tout. When the water flow rate of the exchanger 10 is expressed as Q and the combustion heat quantity of the burner 3 is expressed as P, it is given in advance as shown in the following equation (1), and this arithmetic expression data is stored in the data storage unit 42 in advance. ing.
[0034]
η = k · (Tout -Tin) · Q / P (1)
[0035]
Note that k is the specific heat of water (that is, k = 1 (cal / g · deg)).
[0036]
The thermal efficiency detector 45 detects the incoming water temperature Tin supplied to the hot water supply heat exchanger 10 with the incoming water thermistor 30, detects the hot water supply temperature Tout flowing out from the hot water supply heat exchanger 10 with the hot water supply heat exchanger thermistor 31, and the hot water supply heat exchanger The water flow rate Q of 10 is detected by the water amount sensor 28, the combustion heat amount P of the burner 3 is detected from the combustion heat amount information of the combustion heat amount control unit 44, and during the hot water supply single operation, the above formula is used based on the detected information. According to (1), the thermal efficiency η of the hot water supply heat exchanger 10 is calculated and detected every moment.
[0037]
The thermal efficiency change monitoring unit 43 takes in the information of the hot water supply single operation monitoring unit 38 and detects the thermal efficiency η of the hot water supply heat exchanger 10 detected by the thermal efficiency detection unit 45 when detecting that the single hot water supply operation is started based on the monitoring information. The change in thermal efficiency η is monitored as follows. For example, the thermal efficiency change monitoring unit 43 includes a timer (not shown), and the data storage unit 42 correlates the detected thermal efficiency η of the hot water supply heat exchanger 10 with the degree of capture from the thermal efficiency detector 45 and the thermal efficiency η corresponding to time. To store. And the thermal efficiency change monitoring part 43 of time tb (for example, 6 seconds) with respect to thermal efficiency (eta) a of the hot water supply heat exchanger 10 when time ta (for example, 3 seconds) immediately after the hot water supply independent operation is started passes. The slope m (m = (ηb−ηa) / (tb−ta)) = Δη / Δt) of the change in the thermal efficiency ηb of the hot water supply heat exchanger 10 is obtained and the slope m of the change in the thermal efficiency η is monitored.
[0038]
FIG. 2 shows a graph showing a change example of the thermal efficiency η of the hot water supply heat exchanger 10 after the hot water supply single operation is started. The solid line A shown in the figure shows the change in the thermal efficiency η when there is hot water in the reheating heat exchanger 14, and the chain line B shows the change in the heat efficiency η when there is no hot water in the reheating heat exchanger 14. Yes. As shown by the solid line A and the chain line B, the slope m (Δη / Δt) of the change in the thermal efficiency η of the hot water heat exchanger 10 immediately after the start of the hot water single operation is the presence or absence of hot water in the reheating heat exchanger 14. It depends on.
[0039]
This is due to the following reasons. In the single-can two-water bath water heater, the hot water supply heat exchanger 10 and the reheating heat exchanger 14 are integrated, so that heat is exchanged between the hot water supply heat exchanger 10 and the reheating heat exchanger 14. . Since the temperature in the reheating heat exchanger 14 is low when the hot water supply independent operation is started, the amount of heat absorbed by the reheating heat exchanger 14 from the hot water heat exchanger 10 heated by the burner combustion is large and the hot water heat exchanger 10 The heat efficiency η is low, and the amount of heat absorbed from the hot water heat exchanger 10 to the reheating heat exchanger 14 decreases as the temperature in the reheating heat exchanger 14 increases due to the above-described heat absorption. The solid line A and the chain line in FIG. As shown in B, the thermal efficiency η of the hot water supply heat exchanger 10 increases, but the specific heat of air is smaller than the specific heat of water, and the weight of air is much lighter than the weight of water of the same volume as the volume of the air. Therefore, the temperature in the reheating heat exchanger 14 rises faster when the inside is air than when the inside is water, and as a result, hot water is added to the reheating heat exchanger 14. If it is air and there is no air The rising slope m of the thermal efficiency η of the hot water supply heat exchanger 10 is significantly greater than when hot water is present in the exchanger 14.
[0040]
As described above, the slope m (Δη / Δt) of the change in the thermal efficiency η of the hot water supply heat exchanger 10 immediately after the start of the single hot water supply operation differs depending on the presence or absence of hot water in the reheating heat exchanger 14, so that The presence or absence of hot water in the reheating heat exchanger 14 can be determined by the magnitude of the slope m of the change in the thermal efficiency η of the hot water supply heat exchanger 10 immediately after the start of operation.
[0041]
As shown by the solid line A and the chain line B in FIG. 2, the thermal efficiency η of the hot water supply heat exchanger 10 increases immediately after the hot water supply single operation is started, but the temperature in the reheating heat exchanger 14 is, for example, 80 When the temperature rises to about ˜90 ° C. and the temperature rise hardly disappears, the thermal efficiency η of the hot water supply heat exchanger 10 hardly changes at a constant value regardless of the presence or absence of hot water in the reheating heat exchanger 14. In order to determine the presence / absence of hot water in the reheating heat exchanger 14 using the change in the thermal efficiency of the water heater 10, the hot water supply immediately after the hot water supply single operation, where a large difference appears depending on the presence / absence of hot water in the reheating heat exchanger 14, is shown. The inclination of the change in the thermal efficiency of the heat exchanger 10 is used.
[0042]
In the data storage unit 42, the inclination of the change in the thermal efficiency η of the hot water supply heat exchanger 10 as a threshold value for determining whether or not there is hot water in the reheating heat exchanger 14 is determined in advance by experiments or calculations. Sought and stored.
[0043]
The reheating heat exchanger hot / cold water presence / absence determination unit 40 takes in the information of the hot water supply single operation monitoring unit 38 and, based on this monitoring information, detects that the hot water supply single operation has started, the hot water supply heat obtained by the thermal efficiency change monitoring unit 43. The inclination m of the change in the thermal efficiency η of the exchanger 10 is taken in, and the inclination m of the change in the thermal efficiency η is compared with the threshold value of the data storage unit 42. The inside of the heat exchanger 14 is air, that is, it is determined that there is no hot water in the reheating heat exchanger 14, and a no water signal is output to indicate that there is no hot water in the reheating heat exchanger 14. An absence flag is set in the data storage unit 42.
[0044]
The reheating heat exchanger hot / cold water presence / absence determination unit 40 determines that there is hot water in the reheating heat exchanger 14 when the slope m is equal to or less than the threshold value, and enters the reheating heat exchanger 14. A water presence signal indicating the presence of hot water is output, and when the water absence flag is set in the data storage unit 42, the water absence flag is defeated.
[0045]
When the hot water filling control unit 41 detects that a hot water filling start command has been issued, for example, by pressing the hot water filling start button of the remote controller 36, the hot water filling control unit 41 determines whether or not the no water flag is set in the data storage unit 42. When it is determined that the no water flag is set in the data storage unit 42, it is determined that there is no hot water in the reheating heat exchanger 14, and at this time, the circulation pump 16 and the water flow switch 34 as described above are used. The operation for determining the presence or absence of hot water in the reheating heat exchanger 14 is omitted, that is, the operations in steps 101 and 102 in FIG. 4 are omitted, and the hot water filling is started from the operation in step 103 (pouring operation). .
[0046]
In other cases, that is, when the no water flag is not raised in the data storage unit 42, as described above, the hot water filling control unit 41 performs the operations of steps 101 and 102 in FIG. After confirming that hot water is present in the vessel 14, the operation proceeds to the next hot water operation. The reason for this is that, as described above, the hot-water heat exchanger presence / absence determining unit 40 determines that there is hot water in the hot-water heat exchanger 14 and the hot water filling operation is started until the hot water filling operation is started. Therefore, even if it is determined by the reheating heat exchanger hot / cold water presence / absence determination unit 40 that there is hot water in the reheating heat exchanger 14, the reheating heat exchanger 14 is used for confirmation. After the presence or absence of hot water in the inside, that is, the presence or absence of hot water in the bathtub 17 is determined, the operation proceeds to the next hot water filling operation.
[0047]
According to this embodiment, the reheating heat exchanger hot water for determining the presence or absence of hot water in the reheating heat exchanger 14 based on the slope m of the change in the thermal efficiency η of the hot water supply heat exchanger 10 immediately after the start of the single hot water supply operation. Since the presence / absence determination unit 40 is provided, the presence / absence of hot water in the reheating heat exchanger 14 can be detected in advance before the hot water filling is started.
[0048]
Further, when it is detected that there is no hot water in the reheating heat exchanger 14, when the hot water filling is started, the hot water filling control unit 41 starts the hot water filling from the pouring without driving the circulation pump 16. Therefore, the circulation pump 16 is not driven at the start of hot water filling in which there is no hot water in the reheating heat exchanger 14, and there is no hot water in the reheating heat exchanger 14. In addition to eliminating the wasteful operation of the idling operation, it is possible to eliminate the drive time of the circulation pump 16 at the start of the hot water filling. The time required to finish stretching can be shortened.
[0049]
Further, since the idling of the circulating pump 16 at the start of hot water filling is avoided, the number of idling operations of the circulating pump 16 can be drastically reduced, and the occurrence of a malfunction of the circulating pump 16 due to repeated idling is prevented. It becomes possible.
[0050]
In addition, this invention is not limited to the said embodiment, Various embodiment can be taken. For example, in the above embodiment, the threshold value for determining the presence or absence of hot water in the reheating heat exchanger 14 is one, but in order to determine the presence of water in the reheating heat exchanger 14. And a water absence judgment threshold value that is larger than the water presence judgment threshold value for judging the water absence state in the reheating heat exchanger 14 may be provided separately.
[0051]
In such a case, the reheating heat exchanger hot / cold water presence / absence determination unit 40 determines the slope m of the change in the thermal efficiency η of the hot water supply heat exchanger 10 detected by the thermal efficiency change monitoring unit 43 as the water absence determination threshold, When the slope m is larger than the water absence judgment threshold value, respectively, it is judged that there is no hot water in the reheating heat exchanger 14, and a water absence signal is output. When m is equal to or less than the threshold value for determining whether there is water, it is determined that there is hot water in the reheating heat exchanger 14 and a signal indicating the presence of water is output. The hot water filling control unit 41 uses the circulation pump 16 and the water flow switch 34 when performing hot water filling after the no-water signal is output by the reheating heat exchanger hot / cold water presence / absence judgment unit 40 as in the above embodiment. The hot water filling operation is started from the pouring operation without determining the presence or absence of hot water in the reheating heat exchanger 14.
[0052]
Furthermore, in the above embodiment, the hot water filling operation is performed according to the flowchart shown in FIG. 4. However, after the hot water in the reheating heat exchanger 14 is determined using the circulation pump 16 and the water flow switch 34, the hot water filling operation is performed. As long as the hot water filling operation performs hot water, the operation is not limited to the operation of the flowchart shown in FIG.
[0053]
Further, in the above embodiment, the thermal efficiency detection unit 45 takes in the information of the combustion heat quantity P from the combustion heat quantity control unit 44, but detects the valve opening degree of the proportional valve 8, that is, detects the proportional valve drive current. It may be taken in as information on the combustion heat quantity P.
[0054]
Further, in the above-described embodiment, the thermal efficiency change monitoring unit 43 has a slope m of the change in the thermal efficiency ηb of the hot water supply heat exchanger 10 at the time tb relative to the thermal efficiency ηa of the hot water supply heat exchanger 10 at the predetermined time ta. For example, the change in the thermal efficiency η of the hot water supply heat exchanger 10 is monitored. For example, the inclination of the change in the thermal efficiency η of the hot water supply heat exchanger 10 at predetermined time intervals (for example, every 0.1 second). , And an average of the slopes of the change in the obtained thermal efficiency η for a predetermined time (for example, 10 seconds) is obtained to obtain the thermal efficiency as the slope m of the change in the thermal efficiency η of the hot water supply heat exchanger 10 immediately after the start of the hot water supply independent operation The slope of the change in η may be monitored.
[0055]
Further, in the above embodiment, when the reheating heat exchanger hot / cold water presence / absence determination unit 40 determines that there is no hot water in the reheating heat exchanger 14, it outputs a no water signal and sets a no water flag to reheat the heat. When it is determined that there is hot water in the exchanger 14, a water presence signal is output and the above-mentioned no-water flag is turned off, but the reheating heat exchanger hot / cold water presence / absence determination unit 40 detects that hot water is present in the reheating heat exchanger 14. When it is determined that there is a water signal, a water flag is set. When it is determined that there is no hot water in the reheating heat exchanger 14, a water signal is output. The presence flag may be defeated, and in this case, the hot water filling control unit 41 causes hot water in the reheating heat exchanger 14 when the hot water flag is not set when the hot water filling start command is issued. But The Most determines, in the same manner as in the above embodiment, to start the water filling the pouring operation is omitted hot water presence determination operation of the circulation pump 16 and the water flow switch 34 to follow the fired heat exchanger 14 utilizing.
[0056]
By the way, a large amount of bathtub water is used or drained while the water flag is standing, the water level of the bathtub 6 becomes lower than that of the circulation fitting 19, and air enters the recirculation circulation passage 21, and the water flag is set. Since there is a possibility that there is no hot water in the reheating heat exchanger 14 while standing, in order to prevent the situation from occurring, a bathtub hot / cold water monitoring unit 46 shown by a dotted line in FIG. 1 is provided. It is desirable.
[0057]
The bathtub hot / cold water monitoring unit 46 detects the water level of the bathtub detected by the water level sensor 32 after the water flow switch 34 detects the circulating water flow in the recirculation circulation passage 21 by driving the circulation pump 16 by reheating operation or hot water filling operation. The bath water level is monitored every moment, and when a predetermined aeration water level (for example, a water level lower than the upper end of the circulation fitting 19) is detected by the water level sensor 32, air is introduced into the recirculation circulation passage 21. It is determined that there is a possibility of entering, and the water heat flag set by the reheating heat exchanger hot / cold water presence / absence determination unit 40 is defeated.
[0058]
By providing the bathtub hot / cold water monitoring unit 46, when the bathtub hot water level drops below the circulating metal fitting 19 and the hot water is exhausted in the reheating heat exchanger 14, the water present flag is defeated. The state of the presence or absence of hot water in the reheating heat exchanger and the state of the water presence flag can be substantially matched, and there is a situation in which there is a water present flag even though there is no hot water in the reheating heat exchanger 14. Can be almost avoided.
[0059]
In addition, if hot water is used or drained after hot water is applied to the water level above the circulating metal fitting 19 by hot water filling operation or the like, and the bathtub water level falls below the circulating metal fitting 19, air is replenished in the recirculation circulation passage 21. Therefore, after the water level below the circulation fitting 19 is detected by the water level sensor 32, the water level sensor 32 cannot accurately detect the bathtub water level due to the air in the recirculation circulation passage 21. Therefore, after the water level below the circulating metal 19 is detected by the water level sensor 32 after the hot water is filled up to the water level above the circulating metal 19 by hot water filling operation or the like, the circulating metal Even if a water level higher than 19 is detected, it is determined that hot water has entered the heat exchanger 14 after the water level of the bathtub is replenished above the circulating metal fitting 19. Can not.
[0060]
Even if air enters the recirculation circulation passage 21 as described above, the air in the recirculation circulation passage 21 is pushed out to the bathtub 6 by the hot water flow due to the hot water operation or the circulation water flow of the circulation pump 16 due to the reheating operation. The water level sensor 32 can detect the bathtub water level again with high accuracy after the water flow sensor 34 detects the water flow in the recirculation circulation passage 21 by the hot water operation or the reheating operation.
[0061]
【The invention's effect】
According to the present invention, the reheating heat exchanger hot / cold water presence / absence determination unit that determines the presence / absence of hot water in the reheating heat exchanger based on the gradient of the change in the thermal efficiency of the hot water heat exchanger with respect to the elapse of time immediately after the start of the hot water supply independent operation. Therefore, it is possible to easily determine the presence or absence of hot water in the reheating heat exchanger while performing a single hot water supply operation. Conventionally, for example, at the start of hot water filling, the circulating pump is operated to drive the circulating pump. In the present invention, the presence or absence of hot water in the reheating heat exchanger was determined based on the presence or absence of the circulating water flow in the recirculation circulation passage. As described above, the presence or absence of hot water in the reheating heat exchanger can be detected in advance.
[0062]
When hot water filling is performed after the no-water signal is output by the reheating heat exchanger hot water presence / absence determination unit, or the no-water signal is output by the reheating heat exchanger hot / cold water presence / absence determination unit and the no water flag is set. Or when there is no water signal and the water presence flag is turned off by the reheating heat exchanger hot / cold water presence / absence judgment unit, the reheating heat exchanger depends on the presence or absence of the circulating water flow in the recirculation circulation passage by driving the circulation pump. For those equipped with a hot water filling control unit that drops hot water into the bathtub without performing the operation of judging the presence or absence of hot water in the hot water, even if there is no hot water in the heat exchanger that is replenished at the start of hot water filling. Therefore, the idling operation in which the circulation pump is driven can be avoided, and a wasteful operation due to the idling operation can be omitted. Further, the number of idling operations of the circulation pump is remarkably reduced, and the probability of occurrence of a problem such as a malfunction of the circulation pump due to repeated idling can be greatly reduced.
[0063]
Furthermore, when the hot water filling control unit omits the hot water presence / absence judgment operation in the reheating heat exchanger using the circulation pump at the start of hot water filling, the hot water filling presence / absence judgment operation is omitted and the hot water filling is required. Time can be shortened.
[0064]
In the case of a structure having a bathtub hot / cold water monitoring unit, a water presence flag set by the reheating heat exchanger hot / cold water presence / absence determination unit when a predetermined aerated water level is detected by the water level detection means is set. To avoid the situation where the bathtub water level drops and hot water comes out of the reheating heat exchanger and there is no hot water in the reheating heat exchanger because there is no hot water in the reheating heat exchanger. Can do.
[0065]
In the case where the threshold value for determining whether there is no water and the threshold value for determining whether there is water are provided separately, it is possible to determine the presence or absence of hot water in the reheating heat exchanger as well as the above. It is possible to determine the case where water and air are mixed in the exchanger.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a characteristic control configuration in an embodiment according to the present invention.
FIG. 2 is a graph showing an example of a change in thermal efficiency η of a hot water supply heat exchanger during a single hot water supply operation.
FIG. 3 is an explanatory diagram showing a model example of a single can / two water bath hot water heater.
FIG. 4 is a flowchart showing an example of a hot water filling operation.
[Explanation of symbols]
3 Burner
10 Hot water supply heat exchanger
14 Reheating heat exchanger
16 Circulation pump
21 Recirculation circulation passage
34 Water flow switch
40 Reheating heat exchanger hot / cold water judging section
41 Hot water filling control unit
43 Thermal efficiency change monitoring unit
46 Bathtub monitoring section
