JP3844113B2

JP3844113B2 - Water heater with anti-freezing function

Info

Publication number: JP3844113B2
Application number: JP2000256496A
Authority: JP
Inventors: 信義神谷; 秀一吉川; 宏明田中; 公明朝野
Original assignee: Noritz Corp
Current assignee: Noritz Corp
Priority date: 2000-08-25
Filing date: 2000-08-25
Publication date: 2006-11-08
Anticipated expiration: 2020-08-25
Also published as: JP2002071210A

Description

【０００１】
【発明の属する技術分野】
本発明は、給湯器、追い焚き循環機能付き給湯器、温水循環式暖房機能付き給湯器、あるいは、追い焚き循環・暖房機能付き給湯器等を対象として配管内にある湯水の凍結を防止するために用いられる凍結防止機能付き給湯器に関する。
【０００２】
【従来の技術】
従来より、この種の給湯器においては、冬期等に屋外配管もしくは屋内配管やこれらの配管に接続された種々の端末等の内部に滞留している水もしくはお湯等の湯水が運転停止中に内部で凍結しないように一時的に強制流動させることが行われている。例えば、暖房機能付き給湯器においては、暖房回路に温水を循環させるために設置されている循環ポンプを暖房運転が停止中であっても凍結が予想される温度条件が成立する場合には強制的に間欠運転させ、上記暖房回路内に湯水を間欠的に循環させるという凍結防止運転が行われる場合がある。また、上記配管等にヒータを設置しておき、凍結が予想される温度条件の成立によりそのヒータにより加温することも行われている。
【０００３】
【発明が解決しようとする課題】
ところが、上記の暖房機能付き給湯器が例えば給湯回路と暖房回路とが１缶２回路式の熱交換缶体に共に導かれて共通の燃焼バーナにより加熱されるものである場合には、凍結防止運転中に給湯回路による給湯運転が行われると次のような不都合が生じる場合がある。すなわち、上記給湯運転及び暖房回路による暖房運転が共に停止されて上記の如く循環ポンプを強制運転させるという凍結防止運転が行われている最中に給湯運転が開始されると、その給湯運転による上記燃焼バーナの燃焼作動により給湯回路のみならず暖房回路も加熱されることになる。このため、暖房運転が停止中であるにも拘わらずその暖房回路に対し予期しない高温の温水が供給されてしまう場合が生じてしまうことになる。
【０００４】
また、給湯器が給湯回路に加えて追い焚き循環回路が１缶２回路式の熱交換缶体に導かれて共通の燃焼バーナにより加熱されるものである場合には、その追い焚き循環回路に設置されている循環ポンプを強制運転させるという凍結防止運転を行っている最中に給湯運転が開始されると、その給湯運転による燃焼バーナの燃焼作動により給湯回路のみならず追い焚き循環回路も加熱されることになる。そのため、前夜の浴槽使用後に浴槽内の残水が特に少ない場合にはその残水が沸き上がってしまうおそれがある。
【０００５】
さらに、上記の追い焚き循環回路の途中に例えば暖房切換ユニットを介して暖房回路が分岐接続されている場合には、追い焚き循環回路の循環ポンプを強制作動させて上記暖房回路についての凍結防止運転を行っている最中に給湯運転が開始されると、給湯運転のための燃焼バーナの燃焼開始により高温に加熱された温水が上記暖房切換ユニットや暖房端末側に供給されてしまい、上記と同様に暖房運転の停止中であるにも拘わらず予期しない高温の温水が供給されてしまうことにもなる。
【０００６】
加えて、給湯器が給湯単独のものであり、その給湯回路に対し凍結防止のためにヒータ加熱を行うものである場合、凍結が予想される温度条件の成立によりヒータを加熱作動させる凍結防止運転を行っている最中に給湯運転が開始されたとき、給湯運転により加熱された湯水が給湯回路に通されているにも拘わらず上記の凍結防止運転を継続することはヒータ作動のための電力等のエネルギーの損失を招くことにもなる。
【０００７】
本発明は、このような事情に鑑みてなされたものであり、その目的とするところは、凍結防止運転中に給湯運転が開始された場合に生じる種々の不都合を解消することにある。
【０００８】
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【０００９】
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【００１０】
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【００１１】
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【００１２】
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【００１３】
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【００１５】
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【００１６】
【課題を解決するための手段】
上記目的を達成するために、請求項１に係る発明は、循環ポンプを介装した循環加熱回路と給湯回路とが共通の加熱源により加熱されるよう構成された１缶２回路式加熱缶体と、上記循環加熱回路の凍結防止のために上記循環ポンプを作動させて上記循環加熱回路内に湯水を強制循環させる凍結防止運転を行う凍結防止手段とを備えた凍結防止機能付き給湯器を対象として以下の特定事項を備えるものとする。すなわち、上記循環加熱回路を給湯回路側と熱的に遮断されるよう切換可能に切換えて上記循環加熱回路内の循環水に対する上記加熱缶体からの熱の授受を阻止する熱的遮断切換手段を備える。加えて、上記凍結防止手段として、その凍結防止運転の実行中に上記給湯回路を用いた給湯運転が開始されたとき、上記熱的遮断切換手段により上記循環加熱回路を給湯回路側と熱的に遮断された状態に切換える構成とすることを特定事項とするものである。
【００１７】
この請求項１によれば、凍結が予想される温度条件の成立により凍結防止手段による凍結防止運転が開始され、これに伴う循環ポンプの強制作動により循環加熱回路内の湯水が循環加熱回路を強制循環される。この凍結防止運転が行われている最中に給湯運転が開始されると、上記熱的遮断切換手段による切換えにより上記循環加熱回路が給湯回路側と遮断されて循環加熱回路内の循環水に対する加熱缶体からの熱の授受が阻止されることになる。このため、たとえ１缶２回路式加熱缶体において給湯運転の開始により循環加熱回路と給湯回路とが共通の加熱源により共に加熱されることになったとしても、凍結防止運転に基づく循環ポンプの作動継続より循環加熱回路内に循環されている循環水に対しては加熱されず、循環加熱回路の循環供給先に対して予期せぬ高温の循環水が供給されることが回避される。
【００１８】
請求項２に係る発明は、請求項１の「熱的遮断切換手段」に包含される具体的事項を特定したものであり、循環ポンプを介装した循環加熱回路と給湯回路とが共通の加熱源により加熱されるよう構成された１缶２回路式加熱缶体と、上記循環加熱回路の凍結防止のために上記循環ポンプを作動させて上記循環加熱回路内に湯水を強制循環させる凍結防止運転を行う凍結防止手段とを備えた凍結防止機能付き給湯器を対象として以下の特定事項を有するものである。すなわち、上記循環加熱回路として、この循環加熱回路を構成する往き管及び戻り管を互いに接続して上記加熱缶体をバイパスするバイパス管と、上記循環加熱回路の循環経路を上記加熱缶体を経由する加熱循環路及び上記加熱缶体をバイパスして上記バイパス管を経由するバイパス循環路のいずれか一方に相互に切換えるバイパス用切換手段とを備えるものとする。加えて、上記凍結防止手段として、その凍結防止運転の実行中に上記給湯回路を用いた給湯運転が開始されたとき、上記バイパス用切換手段を切換えることにより上記循環加熱回路の循環経路をバイパス循環路に切換える構成とすることを特定事項とする。
【００１９】
この請求項２によれば、凍結が予想される温度条件の成立により凍結防止手段による凍結防止運転が開始され、これに伴う循環ポンプの強制作動により循環加熱回路内の湯水が循環加熱回路を強制循環される。この凍結防止運転が行われている最中に給湯運転が開始されると、バイパス用切換手段が切換えられて循環加熱回路の循環経路がバイパス循環路に切換えられるため、上記循環加熱回路内の循環水は１缶２回路式の加熱缶体を経由せずにバイパス管を通して循環供給先との間で循環されることになる。このため、上記循環経路の切換え前の加熱循環路が上記加熱缶体において給湯運転の開始により循環加熱回路と給湯回路とが共通の加熱源により共に加熱されることになったとしても、上記バイパス循環路を循環されている循環水に対しては加熱缶体からの熱の授受は行われず、循環加熱回路は給湯運転に伴い加熱缶体で加熱される給湯回路側とは熱的に遮断されることになる。このため、凍結防止運転中に給湯運転が一時的に行われたとしても、循環加熱回路の循環供給先に対して予期せぬ高温の循環水が供給されることが回避される。
【００２０】
請求項３に係る発明は、請求項２の「循環加熱回路」に包含される具体的事項を特定したものであり、循環ポンプを介装した循環加熱回路と給湯回路とが共通の加熱源により加熱されるよう構成された１缶２回路式加熱缶体と、上記循環加熱回路の凍結防止のために上記循環ポンプを作動させて上記循環加熱回路内に湯水を強制循環させる凍結防止運転を行う凍結防止手段とを備えた凍結防止機能付き給湯器を対象として以下の特定事項を有する。すなわち、上記循環加熱回路として、加熱缶体と浴槽との間を循環ポンプの作動により循環可能に接続する追い焚き循環回路と、この追い焚き循環回路の途中から暖房用切換手段を介して分岐され上記循環ポンプの作動により上記加熱缶体と暖房端末との間を循環可能に接続する暖房回路と、上記暖房用切換手段よりも加熱缶体側位置において上記追い焚き循環回路を構成する往き管及び戻り管を互いに接続して上記加熱缶体をバイパスするバイパス管と、上記循環加熱回路の循環経路を上記加熱缶体を経由する加熱循環路及び上記加熱缶体をバイパスして上記バイパス管を経由するバイパス循環路のいずれか一方に相互に切換えるバイパス用切換手段とを備えるものとする。加えて、上記凍結防止手段として、上記暖房用切換手段の選択的切換えにより上記追い焚き循環回路及び暖房回路のいずれか一方もしくは双方に対する凍結防止運転を選択的に実行可能に構成するとともに、その凍結防止運転の実行中に上記給湯回路を用いた給湯運転が開始されたとき上記バイパス用切換手段を切換えることにより上記循環加熱回路の循環経路をバイパス循環路に切換える構成とすることを特定事項とする。
【００２１】
この請求項３によれば、凍結が予想される温度条件が成立すれば、上記凍結防止手段により暖房用切換手段の選択的切換えにより追い焚き循環回路のみ、暖房回路のみ、あるいは、追い焚き循環回路及び暖房回路の双方が連通するよう選択され、この状態で循環ポンプが強制作動されることにより上記で選択された回路を対象として凍結防止運転が開始される。そして、この凍結防止運転が行われている最中に、もしも給湯運転が開始されると、バイパス用切換手段が切換えられて循環加熱回路の循環経路がバイパス循環路に切換えられるため、上記循環加熱回路内の循環水は１缶２回路式の加熱缶体を経由せずにバイパス管を通して循環供給先との間で循環されることになる。このため、上記循環経路の切換え前の加熱循環路が上記加熱缶体において給湯運転の開始により循環加熱回路と給湯回路とが共通の加熱源により共に加熱されることになったとしても、上記バイパス循環路を循環している循環水に対しては加熱缶体からの熱の授受は行われず、循環加熱回路は給湯運転に伴い加熱缶体で加熱される給湯回路側とは熱的に遮断されることになる。これにより、追い焚き循環回路を対象として凍結防止運転が行われた場合においては浴槽内の湯水の沸き上がりのおそれを確実に回避し得る一方、暖房回路を対象として凍結防止運転が行われた場合においては暖房端末に対し高温の温水が供給されることを確実に回避し得る。加えて、いずれの回路が選択された場合においても、暖房用切換手段に対し高温水が供給されることも回避し得る。
【００２２】
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【００２３】
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【００２６】
【発明の効果】
以上、説明したように、請求項１に係る凍結防止機能付き給湯器によれば、循環ポンプの強制作動による循環加熱回路に対する凍結防止運転が行われている最中に給湯運転が開始されて１缶２回路式加熱缶体での加熱源による加熱が開始されたとしても、給湯回路側との熱的遮断により循環加熱回路内の循環水に対する加熱缶体からの熱の授受を阻止することができる。このため、たとえ凍結防止運転に基づく循環ポンプの作動を継続しても、循環加熱回路内に循環している循環水に対する加熱を回避して、循環加熱回路の循環供給先に対して予期せぬ高温の循環水が供給されることを確実に回避することができる。
【００２７】
請求項２に係る凍結防止機能付き給湯器によれば、循環ポンプの強制作動による循環加熱回路に対する凍結防止運転が行われている最中に給湯運転が開始されて１缶２回路式加熱缶体での加熱源による加熱が開始されたとしても、バイパス用切換手段が切換えられて循環加熱回路の循環経路がバイパス循環路に切換えられるため、循環加熱回路内の循環水に対する給湯回路側との熱的遮断を確実に行うことができ、上記循環水に対する加熱缶体からの熱の授受を阻止することができる。このため、凍結防止運転中に給湯運転が一時的に行われたとしても、循環加熱回路の循環供給先に対して予期せぬ高温の循環水が供給されることを確実に回避することができる。
【００２８】
請求項３に係る凍結防止機能付き給湯器によれば、凍結防止手段による暖房用切換手段の選択的切換えにより追い焚き循環回路のみ、暖房回路のみ、あるいは、追い焚き循環回路及び暖房回路の双方を対象として循環ポンプの強制作動による凍結防止運転を行うことができることになる。その一方、凍結防止運転が行われている最中に給湯運転が開始されて１缶２回路式加熱缶体での加熱源による加熱が開始されたとしても、バイパス用切換手段が切換えられて循環加熱回路の循環経路がバイパス循環路に切換えられるため、請求項２と同様に循環加熱回路内の循環水に対する給湯回路側との熱的遮断を確実に行うことができ、上記循環水に対する加熱缶体からの熱の授受を阻止することができる。このため、凍結防止運転中に給湯運転が一時的に行われたとしても、循環加熱回路の循環供給先に対して予期せぬ高温の循環水が供給されることを確実に回避することができる。これにより、凍結防止運転の対象が追い焚き循環回路である場合には浴槽内の湯水の沸き上がりのおそれを確実に回避することができる一方、上記対象が暖房回路である場合には暖房端末に対し高温の温水が供給されることを確実に回避することができる。加えて、いずれの回路が選択された場合においても暖房用切換手段に対する高温水の供給をも回避することができる。
【００２９】
【発明の実施の形態】
以下、本発明の実施形態を図面に基づいて説明する。
【００３０】
図１は、本発明の凍結防止機能付き給湯器が適用される後述の第１実施形態及び第２実施形態の前提となる給湯器を示す。この給湯器は、給湯回路２による給湯機能と、追い焚き循環回路３による追い焚き循環機能と、この追い焚き循環回路３に対し温水分岐ユニット４を介して併設された暖房回路５による温水循環式の暖房機能との３つの機能を有し、上記給湯回路２の第１熱交換器１２及び追い焚き循環回路３の第２熱交換器３２が共に１つの加熱缶体としての燃焼缶体６において共通の加熱源としての１つの燃焼バーナ７の燃焼熱との熱交換により加熱される１缶２回路式に構成されたものである。そして、上記追い焚き循環回路３及び第２熱交換器３２を共用した暖房回路５が本発明の循環加熱回路を構成している。
【００３１】
上記給湯回路２は、水道管と接続され水道水を上記第１熱交換器１２に入水する入水管１１と、上記第１熱交換器１２で加熱されたお湯を出湯する出湯管１３と、この出湯管１３の出湯に対し水道水を混合するためのバイパス管１４とを備えている。上記出湯管１３にはカラン１５等への一般給湯管１６が接続される一方、浴槽Ｂにお湯を注湯して湯張りするための風呂注湯回路８の注湯管８１が分岐接続されている。そして、上記入水管１１には入水温度を検出する入水サーミスタ１７及び入水流量センサ１８が設けられる一方、上記出湯管１３には上記バイパス管１４の下流端との合流位置よりも上流側位置に出湯温度を検出する出湯サーミスタ１９が設けられ、上記合流位置よりも下流側位置に給湯量制御弁２０及び給湯サーミスタ２１が設けられている。また、上記バイパス管１４には比例弁２２が介装されている。なお、同図中１０はＦ点サーミスタであり、このＦ点サーミスタ１０により給湯器近傍の外気温が検出されるようになっている。
【００３２】
また、上記追い焚き循環回路３は、浴槽Ｂ内の湯水を循環ポンプ３１の作動により第２熱交換器３２に戻す戻り管３３と、第２熱交換器３２での加熱により昇温された湯水を上記浴槽Ｂに流す往き管３４と、上記第２熱交換器３２をバイパスするバイパス管３５とを備えている。上記循環ポンプ３１と戻り管３３と往き管３４とにより、浴槽Ｂと第２熱交換器３２との間で湯水の循環を行いながら追い焚きを行うようになっている。一方、上記バイパス管３５は、上記戻り管３３の第２熱交換器３２側位置に介装されたバイパス用切換手段としての三方切換弁３６により上流端が分岐され、下流端が上記往き管３４の第２熱交換器３２下流側位置に連通されている。そして、通常の追い焚き運転や後述の暖房運転の場合には、上記三方切換弁３６はバイパス管３５側を遮断して上・下流側の戻り管３３を連通させた状態にされ、所定の運転状態において後述のコントローラ９により切換制御が行われるようになっている。
【００３３】
上記戻り管３３には、上記三方切換弁３６よりも上流側（浴槽Ｂ側）位置において、上記循環ポンプ３１に加え、圧力検出により浴槽Ｂ内の水位を検出する水位検出センサ３７、水流スイッチ３８及び浴槽Ｂ内の湯水温度を検出する風呂入水サーミスタ３９がそれぞれ介装されている。また、上記往き管３４には上記バイパス管３５との連通位置の直下流側位置に温度センサ４０が介装されており、この温度センサ４０により第２熱交換器３２で加熱された加熱循環水もしくは上記バイパス管３５を通して循環されるバイパス循環水の各温度が検出されて上記コントローラ９に出力されるようになっている。
【００３４】
合わせて、風呂注湯回路８について説明すると、この風呂注湯回路８は上記戻り管３３及び往き管３４の双方に対し注湯して浴槽Ｂに対する注湯を戻り管３３及び往き管３４の双方を通して両搬送式により行うようになっている。すなわち、上記出湯管１３から分岐した注湯管８１は注湯流量センサ８２が介装された後、その下流側が２本の分岐注湯管８３，８４に分岐され、一方の分岐注湯管８３の下流端が上記戻り管３３の三方切換弁３６の直上流側位置に連通され、他方の分岐注湯管８４の下流端が上記往き管３４の温度センサ４０の下流側位置に連通されている。そして、上記両分岐注湯管８３，８４には、それぞれ注湯制御弁８５及び一対の逆止弁８６が設けられている。
【００３５】
暖房回路５は、浴室に設置された暖房端末としての浴室暖房ユニット５１に内蔵された循環供給先としての暖房放熱器５２に対し、温水分岐ユニット４を介して追い焚き循環回路３に流れる湯水を分岐させ、その湯水を循環媒体として循環供給するものである。上記温水分岐ユニット４は暖房用切換手段としての２つの三方切換弁４１，４２と、エアセパレータ４３と、所定の配管とを備えており、その配管に対し上記暖房放熱器５２を接続することにより、暖房回路５が形成されるようになっている。
【００３６】
すなわち、第１三方切換弁４１は追い焚き循環回路３の往き管３４の途中に接続され、その往き管３４により供給される湯水を分岐させて暖房用往き管５３を通して上記暖房放熱器５２に導くようになっている。この暖房放熱器５２において放熱された後の湯水は暖房用戻り管５４を通して上記エアセパレータ４３に対しその上下方向中間位置から戻され、次いで、上記エアセパレータ４３から上記三方切換弁４１，４２の選択的切換状態に応じて第１及び第２のいずれかの分岐戻り管５５，５６を通して追い焚き循環回路３の戻り管３３もしくは往き管３４に対し戻されるようになっている。つまり、後述の追い焚き運転が停止されて暖房運転が行われる場合には上記エアセパレータ４３の底面位置に接続された第１分岐戻り管５５及び第２三方切換弁４２を通して上記戻り管３３に対し戻され、追い焚き運転及び暖房運転が共に行われる場合には上記エアセパレータ４３の頂面位置に接続された第２分岐戻り管５６を通してオーバーフローする湯水が上記往き管３４に対し上記第１三方切換弁４１よりも下流側位置（浴槽Ｂ側位置）に戻される。なお、同図中５７は上記暖房用往き管５３に設けられた暖房サーミスタであり、この暖房サーミスタ５７により暖房放熱器５２に循環供給される湯水の温度が検出されるようになっている。また、同図中５８は浴室暖房ユニット５１に設けられた乾燥機サーミスタであり、この乾燥機サーミスタ５８により暖房放熱器５２に送風される外気の温度が検出されるようになっている。
【００３７】
ここで、追い焚き循環回路３の戻り管３３を、浴槽Ｂから第２三方切換弁４２までを戻り管上流部３３ａ、第２三方切換弁４２から三方切換弁３６までを戻り管中流部３３ｂ、三方切換弁３６から第２熱交換器３２までを戻り管下流部３３ｃとそれぞれ名付けて区分けする。また、同様に往き管３４を、上記第２熱交換器３２からバイパス管３５との連通位置までを往き管上流部３４ａ、その連通位置から第１三方切換弁４１までを往き管中流部３４ｂ、第１三方切換弁４１から浴槽Ｂまでを往き管下流部３４ｃとそれぞれ名付けて区分けする。
【００３８】
そうすると、追い焚き運転が停止状態で温水分岐ユニット４の第１及び第２の両三方切換弁４１，４２が暖房側切換状態に切換えられた場合、つまり、第１三方切換弁４１が往き管下流部３４ｃ側を遮断して往き管中流部３４ｂを暖房用往き管５３と連通させ、かつ、第２三方切換弁４２が戻り管上流部３３ａ側を遮断して戻り管中流部３３ｂを第１分岐戻り管５５と連通させた状態では、暖房回路５において次のような加熱循環路Ｘ及びバイパス循環路Ｙの２つの循環経路を有することになる。
【００３９】
すなわち、三方切換弁３６がバイパス管３５側を遮断して戻り管中流部３３ｂと戻り管下流部３３ｃとを連通させた缶体側切換状態に切換えられると、上記加熱循環路Ｘが形成されることになる。この加熱循環路Ｘにおいては、第２熱交換器３２で加熱された湯水が往き管上流部３４ａ、往き管中流部３４ｂ、第１三方切換弁４１及び暖房用往き管５３を通して暖房放熱器５２に流され、この暖房放熱器５２で放熱された後の湯水が暖房用戻り管５４、エアセパレータ４３、第１分岐戻り管５５、第２三方切換弁４２、戻り管中流部３３ｂ、三方切換弁３６及び戻り管下流部３３ｃを通して再び第２熱交換器に戻されて加熱されるという循環経路となる（図１の実線の矢印参照）。つまり、第２熱交換器３２により加熱された湯水が循環媒体として循環供給先である暖房放熱器５２に対し循環供給されることになる。
【００４０】
逆に、上記三方切換弁３６が戻り管下流部３３ｃ側を遮断して戻り管中流部３３ｂとバイパス管３５とを連通させた缶体遮断切換状態に切換えられると、上記バイパス循環路Ｙが形成されることになる。このバイパス循環路Ｙにおいては、暖房放熱器５２で放熱された後の湯水が暖房用戻り管５４、エアセパレータ４３、第１分岐戻り管５５、第２三方切換弁４２、戻り管中流部３３ｂ及び三方切換弁３６を通してバイパス管３５に流され（図１の一点鎖線の矢印参照）、そのバイパス管３５に流された湯水が往き管中流部３４ｂ、第１三方切換弁４１及び暖房用往き管５３を通して再び暖房放熱器５２に流されるという循環経路となる。つまり、第２熱交換器３２を経由せずに、このため、燃焼バーナ７による燃焼加熱を受けることのない熱的遮断状態の湯水が循環媒体として循環供給先である暖房放熱器５２に対し循環供給されることになる。
【００４１】
上記のバイパス管３５と三方切換弁３６とにより熱的遮断切換手段が構成されることになる。
【００４２】
なお、上記第１及び第２の両三方切換弁４１，４２が暖房＋風呂側切換状態に切換えられて追い焚き運転及び暖房運転が共に行われる場合、つまり、第１三方切換弁４１が往き管下流部３４ｃ側を遮断して往き管中流部３４ｂを暖房用往き管５３と連通させ、かつ、第２三方切換弁４２が第１分岐戻り管５５を遮断して戻り管上流部３３ａと戻り管中流部３３ｂとを連通させた状態においても、上記の如きバイパス用三方切換弁３６の缶体側切換状態と缶体遮断側切換状態との切換えにより加熱循環路Ｘ及びバイパス循環路Ｙの２つの循環経路を有することになる。
【００４３】
一方、上記燃焼缶体６には、上部に燃焼バーナ７がその火炎を下向きに噴射するように配設され、上下方向中間位置に上記第１及び第２の両熱交換器１２，３２が横切るように配設され、下部には熱交換後の燃焼排ガスを排出処理する排煙筒６１が開口されている。
【００４４】
上記燃焼バーナ７は、気体燃料もしくは液体燃料を燃焼させるものであり、本実施形態では石油等の液体燃料を燃焼させるいわゆるリターン式のガンタイプバーナを図示している。この燃焼バーナ７は、電磁開閉弁７１及び電磁供給ポンプ７２が介装された燃料供給管７３により供給された液体燃料を噴霧して燃焼させ、余剰燃料をリターン管７４を通して上記電磁開閉弁７１と電磁供給ポンプ７２との間の燃料供給管７３に対し戻すようになっている。
【００４５】
以上の暖房回路併設の追い焚き循環機能付き給湯器はＭＰＵやメモリー等を備えたコントローラ９により作動制御されるようになっており、このコントローラ９は図示省略の各種のリモコン（リモートコントローラ）を介してユーザによる各種指令の入力設定や状態表示が行われるようになっている。そして、上記コントローラ９は、給湯回路２による給湯運転を行う給湯制御部９１（図２参照）、追い焚き循環回路３による追い焚き運転等を行う風呂制御部９２、暖房回路５による暖房運転を行う暖房制御部９３及び凍結防止運転を行う凍結防止手段としての凍結防止制御部９４もしくは９４′等の各種制御部を備えている。
【００４６】
上記給湯制御部９１による給湯制御においては、ユーザがカラン１５を開いて入水流量センサ１８が最低作動水量以上の流量を検出することにより、燃焼バーナ７の燃焼作動が開始される。まず、入水サーミスタ１７からの入水温度、入水流量センサからの入水流量及び上記リモコンに入力設定された設定出湯温度等の情報に基づいて所定の必要燃焼量により燃焼作動され、以後、出湯サーミスタ１９及び給湯サーミスタ２１からの検出温度に基づいて燃焼制御されて上記カラン１５から設定出湯温度の湯水が出湯されることになる。そして、使用者がカラン１５を閉じて上記入水量センサ１８が最低作動水量より低い流量を検出することにより上記燃焼バーナ７の燃焼が停止される。
【００４７】
上記風呂制御部９２では注湯制御や追い焚き制御が行われ、注湯制御においては、例えばユーザにより上記リモコンに浴槽Ｂへの湯張りのための注湯指令が入力されると、注湯制御弁８５，８５が開状態にされ上記燃焼バーナ７の燃焼作動が開始される。これにより、第１熱交換器１２で加熱された所定温度の湯水が出湯管１３及び注湯管８１，８３，８４を通して戻り管３３及び往き管３４に供給されて浴槽Ｂ内に注湯されることになる。この際の注湯量が注湯流量センサ８２により検出され、水位センサ３７により浴槽Ｂの浴槽水位として所定水位を検出することにより注湯制御が終了される。なお、この注湯制御においては、温水分岐ユニット４の両三方切換弁４１，４２は暖房回路５側を遮断させて上記戻り管３３及び往き管３４を共に浴槽Ｂ側と連通させた風呂単独使用状態に切換制御されるようになっている。
【００４８】
また、例えば上記リモコンに追い焚き指令が入力されると追い焚き制御が行われることになり、まず循環ポンプ３１が作動され、それに伴い水流スイッチ３８がＯＮされると燃焼バーナ７の燃焼作動が開始されることになる。これにより、第２熱交換器３２において戻り管３３を通して戻された浴槽Ｂ内の湯水が上記燃焼バーナ７からの燃焼熱を受けて追い焚きされ、追い焚きされた湯水が往き管３４を通して上記浴槽Ｂに供給されて循環される。そして、風呂入水サーミスタ３９からの検出温度に基づいて浴槽Ｂ内の湯水の温度が設定温度になれば、上記燃焼バーナ７の燃焼作動が停止されることになる。
【００４９】
さらに、例えば上記リモコンに暖房運転指令が入力されると、運転状態の判別を行い、暖房運転が単独で行われる場合には、まず温水分岐ユニット４の第１及び第２の両三方切換弁４１，４２が暖房側切換状態に切換えられると共に、三方切換弁３６が上述の缶体側切換状態に切換えられて加熱循環路Ｘが形成される。次に、循環ポンプ３１が作動されて燃焼バーナ７の燃焼作動が開始される。これにより、第２熱交換器３２で湯水が加熱されながら暖房放熱器５２との間で循環され、所定温度（例えば６０℃）となった湯水の熱が暖房放熱器５２で放熱されて浴室内が暖房されることになる。
【００５０】
以上を共通の前提構成として凍結防止制御において以下の第１及び第２実施形態がある。
【００５１】
＜第１実施形態＞
第１実施形態における凍結防止制御部９４では、図３に示すように、まず、暖房運転及び風呂運転が共に停止中であることを確認した後（ステップＳ１，Ｓ２）、Ｆ点サーミスタ１０により外気温が凍結防止運転を開始するための凍結予防温度まで低下したか否かの判別を行う（ステップＳ３）。外気温が凍結予防温度まで低下している場合（ステップＳ３で「ＹＥＳ」）、及び、外気温が凍結予防温度まで低下していなくても暖房サーミスタ５７により暖房回路５内の滞留水が凍結防止運転を開始するための凍結予防温度まで低下している場合（ステップＳ３で「ＮＯ」でかつステップＳ４で「ＹＥＳ」）には、以下の凍結防止運転を開始する。
【００５２】
すなわち、給湯運転が停止中であることを確認し（ステップＳ５で「ＹＥＳ」）、次いで循環ポンプ３１を強制作動させて循環判定を行う（ステップＳ６，Ｓ７）。この際にはバイパス用三方切換弁３６は缶体側切換状態に、暖房用三方切換弁４１，４２は風呂単独使用状態にそれぞれ切換制御されている。上記循環判定で所定時間（６０ｓｅｃ程度）継続して水量スイッチ３８がＯＮになれば浴槽Ｂ内に所定水位の残水があると判定し、凍結防止運転を暖房回路５及び追い焚き循環回路３の両者について行うべく暖房用三方切換弁４１，４２を上記の暖房＋風呂側切換状態に切換える（ステップＳ７で「ＹＥＳ」，Ｓ８）。一方、上記循環判定で水量スイッチ３８が所定時間継続してＯＮにならない場合には浴槽Ｂ内に所定水位の残水がないと判定し、凍結防止運転を暖房回路５のみについて行うべく暖房用三方切換弁４１，４２を上記の暖房側切換状態に切換える（ステップＳ７で「ＮＯ」，Ｓ９）。いずれの場合も、循環ポンプ３１をタイマ９５（図２参照）によるＯＮタイマ設定時間が経過するまで作動させてから停止する（ステップＳ１０，Ｓ１１）。そして、上記循環ポンプ３１を上記タイマ９５によるＯＦＦタイマ設定時間が経過するまで停止させた後にリターンする。なお、このＯＦＦタイマ設定時間は温度が低い程短くなるように設定され、かつ、浴槽Ｂ内に残水がある場合にはその残水の温度が高い程長くなるように設定されている。
【００５３】
以上の凍結防止運転により、暖房回路５のみが選択された場合（ステップＳ９）には暖房回路５を通して浴室暖房ユニット５１のみに対し、あるいは、暖房回路５及び追い焚き循環回路３の両者が選択された場合（ステップＳ８）には暖房回路５を通しての浴室暖房ユニット５１と追い焚き循環回路３を通しての浴槽Ｂとに対しそれぞれ循環ポンプ３１の間欠作動に基づく強制循環が間欠的に行われて凍結発生が防止されることになる。
【００５４】
一方、上記の凍結防止運転の最中に給湯運転が開始されると、上記のステップＳ５の判別において給湯制御部９１からの出力信号に基づきステップＳ６〜Ｓ１２の各処理が省略されて循環ポンプ３１の作動が強制的にＯＦＦ状態のままにされることになる（ステップＳ５で「ＮＯ」）。これにより、上記給湯運転開始に伴い燃焼バーナ７が燃焼開始されて第１熱交換器１２と共に第２熱交換器３２が加熱されたとしても、その加熱された湯水の暖房ユニット５１もしくは浴槽Ｂ側への循環供給が阻止されることになる。
【００５５】
以上の凍結防止制御において、ステップＳ３の外気温の監視をＦ点サーミスタ１０により行っているが、これに限らず、例えば乾燥機サーミスタ５８により代用させてもよい。
【００５６】
＜第２実施形態＞
第２実施形態における凍結防止制御部９４′（図２参照）では、図４に示すように、まず、暖房運転及び風呂運転が共に停止中であることを確認した後（ステップＳ２１，Ｓ２２）、Ｆ点サーミスタ１０により外気温が凍結防止運転を開始するための凍結予防温度まで低下したか否かの判別を行う（ステップＳ２３）。外気温が凍結予防温度まで低下している場合（ステップＳ２３で「ＹＥＳ」）、及び、外気温が凍結予防温度まで低下していなくても暖房サーミスタ５７により暖房回路５内の滞留水が凍結防止運転を開始するための凍結予防温度まで低下している場合（ステップＳ２３で「ＮＯ」でかつステップＳ２４で「ＹＥＳ」）には、以下の凍結防止運転を開始する。以上の開始条件は第１実施形態と同じである。
【００５７】
まず、給湯運転が停止中であることを確認し（ステップＳ２５で「ＹＥＳ」）、次いでバイパス用三方切換弁３６を缶体側切換状態に切換えた後（ステップＳ２６）、循環ポンプ３１を強制作動させて循環判定を行う（ステップＳ２７，Ｓ２８）。なお、この際には暖房用三方切換弁４１，４２は風呂単独使用状態に切換制御されている。上記循環判定を第１実施形態における循環判定（図３のステップＳ７）と同様に行い、浴槽Ｂ内に所定水位の残水がある場合には凍結防止運転を暖房回路５及び追い焚き循環回路３の両者について行うべく暖房用三方切換弁４１，４２を上記の暖房＋風呂側切換状態に切換える（ステップＳ２８で「ＹＥＳ」，Ｓ２９）。一方、上記循環判定で浴槽Ｂ内に所定水位の残水がない場合には凍結防止運転を暖房回路５のみについて行うべく暖房用三方切換弁４１，４２を上記の暖房側切換状態に切換える（ステップＳ２８で「ＮＯ」，Ｓ３０）。そして、いずれの場合も、循環ポンプ３１を所定時間だけ作動させた後に所定時間だけ停止させるという間欠作動を行行った後に停止状態のままリターンさせるという各処理（ステップＳ３１〜Ｓ３３）を、第１実施形態のステップＳ１０〜Ｓ１２（図３参照）と同様に行う。
【００５８】
以上の凍結防止運転により、第１実施形態と同様に、暖房回路５のみが選択された場合（ステップＳ３０）には暖房回路５を通して浴室暖房ユニット５１のみに対し、あるいは、暖房回路５及び追い焚き循環回路３の両者が選択された場合（ステップＳ２９）には暖房回路５を通しての浴室暖房ユニット５１と追い焚き循環回路３を通しての浴槽Ｂとに対しそれぞれ循環ポンプ３１の間欠作動に基づく強制循環が間欠的に行われて凍結発生が防止されることになる。
【００５９】
一方、上記の凍結防止運転の最中に給湯運転が開始されると、上記のステップＳ２５の判別において給湯制御部９１からの出力信号に基づき上記給湯運転開始が検出され、これにより、バイパス用三方切換弁３６を缶体遮断切換状態に切換制御する（ステップＳ２５で「ＮＯ」、Ｓ３４）。そして、循環ポンプ３１のＯＮ作動、循環判定、暖房用三方切換４１，４２の切換制御、上記循環ポンプ３１の間欠作動の各処理（ステップＳ２７〜Ｓ３３）を上述の給湯運転停止中の場合（ステップＳ２５で「ＹＥＳ」）と同様に行う。この場合には、上記バイパス用三方切換弁３６の缶体遮断切換状態への切換えにより、循環経路がバイパス循環路Ｙに切換えられ、たとえ給湯運転開始に伴い燃焼バーナ７が燃焼開始されて第１熱交換器１２と共に第２熱交換器３２が加熱されたとしても、バイパス循環路Ｙに流れる循環水は加熱されることなく、それまでと同じ条件で間欠的に強制循環されることになる。
【００６０】
なお、以上の第１もしくは第２実施形態では風呂機能及び暖房機能を有する給湯器について説明したが、暖房回路５がなく風呂機能のみを有する給湯器、あるいは、浴槽Ｂまでの循環配管がなく暖房機能のみを有する給湯器に本発明を適用してもよい。もちろん、上記の暖房機能や風呂機能以外の他の機能が付加された給湯器に対し本発明を適用してもよい。
【図面の簡単な説明】
【図１】本発明の第１及び第２実施形態を示す模式図である。
【図２】第１及び第２実施形態のコントローラのブロック構成図である。
【図３】第１実施形態の凍結防止制御部の制御内容を示すフローチャートである。
【図４】第２実施形態の凍結防止制御部の制御内容を示すフローチャートである。
【符号の説明】
２給湯回路
３追い焚き循環回路（循環加熱回路）
５暖房回路（循環加熱回路）
６熱交換缶体（加熱缶体）
７燃焼バーナ（加熱源）
３１循環ポンプ
３５バイパス管（熱的遮断切換手段）
３６三方切換弁（バイパス用切換手段、熱的遮断切換手段）
４１，４２三方切換弁（暖房用切換手段）
５１暖房ユニット（暖房端末）
９４，９４′ 凍結防止制御部（凍結防止制御手段）
Ｙバイパス循環路[0001]
BACKGROUND OF THE INVENTION
  The present invention is intended to prevent freezing of hot water in a pipe for a hot water heater, a hot water heater with a recirculation function, a hot water heater with a hot water circulation heating function, or a hot water heater with a recirculation circulation / heating function. Used forFreezingThe present invention relates to a water heater with an anti-settling function.
[0002]
[Prior art]
  Conventionally, in this type of water heater, water staying inside outdoor pipes or indoor pipes and various terminals connected to these pipes in winter etc. In order to prevent freezing, it is forced to flow temporarily. For example, in a water heater with a heating function, a circulation pump installed to circulate hot water in the heating circuit is compulsory when a temperature condition that is expected to freeze even if the heating operation is stopped is satisfied. In some cases, an anti-freezing operation is performed in which intermittent operation is performed and hot water is circulated intermittently in the heating circuit. In addition, a heater is installed in the pipe or the like, and heating is performed by the heater when a temperature condition in which freezing is expected is established.
[0003]
[Problems to be solved by the invention]
  However, in the case where the water heater with the heating function is such that, for example, the hot water supply circuit and the heating circuit are led together by a single can / two circuit type heat exchange can body and heated by a common combustion burner, freezing prevention If the hot water supply operation is performed by the hot water supply circuit during operation, the following inconvenience may occur. That is, when both the hot water supply operation and the heating operation by the heating circuit are stopped and the anti-freezing operation in which the circulation pump is forcibly operated as described above is being performed, the hot water supply operation is started. The combustion operation of the combustion burner heats not only the hot water supply circuit but also the heating circuit. For this reason, even when the heating operation is stopped, unexpectedly hot water may be supplied to the heating circuit.
[0004]
  In addition, when the water heater is a recirculation circuit in addition to the hot water supply circuit, the recirculation circuit is led to a single can / two circuit type heat exchange can body and heated by a common combustion burner, the recirculation circuit is connected to the recirculation circuit. If the hot water supply operation is started during the freeze prevention operation in which the installed circulation pump is forcibly operated, not only the hot water supply circuit but also the recirculation circuit is heated by the combustion operation of the combustion burner by the hot water supply operation. Will be. Therefore, when there is particularly little residual water in the bathtub after using the bathtub the night before, the residual water may be boiled up.
[0005]
  Further, when the heating circuit is branched in the middle of the recirculation circuit, for example via a heating switching unit, the circulation pump of the recirculation circuit is forcibly operated to prevent freezing operation for the heating circuit. When the hot water supply operation is started during the heating, the hot water heated to a high temperature by the combustion start of the combustion burner for the hot water operation is supplied to the heating switching unit and the heating terminal side, and the same as above In addition, although the heating operation is stopped, unexpectedly hot water is supplied.
[0006]
  In addition, when the water heater is a single hot water supply and heater heating is performed to prevent freezing of the hot water supply circuit, the antifreezing operation that heats the heater when a temperature condition that is expected to freeze is established. When the hot water supply operation is started during the operation, the above freeze prevention operation is continued even though the hot water heated by the hot water supply operation is passed through the hot water supply circuit. It also causes a loss of energy.
[0007]
  This invention is made | formed in view of such a situation, The place made into the objective is to eliminate the various inconvenience which arises, when hot water supply operation is started during freezing prevention operation.
[0008]
(Delete)
[0009]
(Delete)
[0010]
(Delete)
[0011]
(Delete)
[0012]
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[0013]
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[0014]
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[0015]
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[0016]
[Means for Solving the Problems]
In order to achieve the above object, claim 1 is provided.The invention according to the present invention includes a one-can two-circuit heating can body configured such that a circulation heating circuit and a hot water supply circuit provided with a circulation pump are heated by a common heating source, and for preventing the circulation heating circuit from freezing. The following specific matters are provided for a water heater with an anti-freezing function including an anti-freezing means for performing an anti-freezing operation in which the circulating pump is operated to forcibly circulate hot water in the circulation heating circuit. That is, there is provided a thermal cutoff switching means for switching the circulation heating circuit so as to be thermally cut off from the hot water supply circuit side and preventing transfer of heat from the heating can body to the circulating water in the circulation heating circuit. Prepare. In addition, when the hot water supply operation using the hot water supply circuit is started during the execution of the freeze prevention operation, the circulation heating circuit is thermally connected to the hot water supply circuit side by the thermal cutoff switching means. It is a specific matter that the configuration is switched to the blocked state.
[0017]
  This claim1According to the above, the anti-freezing operation by the anti-freezing means is started when the temperature condition where freezing is expected is established, and hot water in the circulation heating circuit is forcibly circulated through the circulation heating circuit by the forced operation of the circulation pump. When the hot water supply operation is started during the freeze prevention operation, the circulating heating circuit is disconnected from the hot water supply circuit side by switching by the thermal cutoff switching means, and the circulating water in the circulating heating circuit is heated. Transfer of heat from the can body will be blocked. For this reason, even if the circulation heating circuit and the hot water supply circuit are heated together by a common heating source by the start of the hot water supply operation in the single can / two circuit heating can body, Since the circulating water circulating in the circulating heating circuit is not heated after the operation is continued, unexpectedly high temperature circulating water is prevented from being supplied to the circulating supply destination of the circulating heating circuit.
[0018]
  Claim2The invention according to claim1Specific item included in the "thermal shut-off switching means" in the above, one can configured so that the circulating heating circuit and the hot water supply circuit interposing the circulating pump are heated by a common heating source Freezing prevention comprising a two-circuit heating can body and anti-freezing means for performing anti-freezing operation in which the circulation pump is operated to forcibly circulate hot water in the circulation heating circuit in order to prevent freezing of the circulation heating circuit. It has the following specific items for hot water heaters with functions. That is, as the circulation heating circuit, a forward pipe and a return pipe constituting the circulation heating circuit are connected to each other to bypass the heating can body, and a circulation path of the circulation heating circuit is routed through the heating can body. And a bypass switching unit that bypasses the heating can body and bypasses the heating can body and switches to either one of the bypass circulation paths that pass through the bypass pipe. In addition, when the hot water supply operation using the hot water supply circuit is started during the execution of the freeze prevention operation, the circulation path of the circulation heating circuit is bypass-circulated by switching the bypass switching means. It shall be a specific matter to adopt a configuration for switching to a road.
[0019]
  This claim2According to the above, the anti-freezing operation by the anti-freezing means is started when the temperature condition where freezing is expected is established, and hot water in the circulation heating circuit is forcibly circulated through the circulation heating circuit by the forced operation of the circulation pump. If the hot water supply operation is started while the freeze prevention operation is being performed, the bypass switching means is switched and the circulation path of the circulation heating circuit is switched to the bypass circulation path, so that the circulation in the circulation heating circuit is performed. Water is circulated between the circulation supply destination through the bypass pipe without passing through the one-can two-circuit heating can body. Therefore, even if the heating circulation path before switching the circulation path is heated by the common heating source in the heating can body, the circulation heating circuit and the hot water supply circuit are both heated by the common heating source. Heat from the heating can body is not transferred to the circulating water circulating in the circulation path, and the circulation heating circuit is thermally cut off from the hot water supply circuit side heated by the heating can body during the hot water supply operation. Will be. For this reason, even if the hot water supply operation is temporarily performed during the freeze prevention operation, unexpectedly high temperature circulating water is prevented from being supplied to the circulation supply destination of the circulation heating circuit.
[0020]
  Claim3The invention according to claim2The specific items included in the “circulation heating circuit” of FIG. 1 are specified, and the canister and the two circuits are configured such that the circulation heating circuit and the hot water supply circuit interposing the circulation pump are heated by a common heating source. With anti-freezing function comprising a heating-type heating can body and anti-freezing means for performing anti-freezing operation for forcibly circulating hot water in the circulating heating circuit by operating the circulating pump to prevent freezing of the circulating heating circuit It has the following specific items for hot water heaters. That is, as the circulation heating circuit, a recirculation circuit that connects the heating can body and the bathtub so as to be circulated by the operation of a circulation pump, and a branch from the middle of the recirculation circuit through the heating switching means. A heating circuit that circulates between the heating can body and the heating terminal by the operation of the circulation pump, and a forward pipe and a return that configure the recirculation circuit at a position closer to the heating can body than the heating switching means A bypass pipe for connecting the pipes to each other and bypassing the heating can body; a circulation path for the circulation heating circuit; a heating circulation path passing through the heating can body; and a bypass pipe bypassing the heating can body Bypass switching means for switching to either one of the bypass circulation paths is provided. In addition, as the anti-freezing means, the anti-freezing operation for one or both of the recirculation circuit and the heating circuit can be selectively executed by selectively switching the heating switching means, and the freezing When the hot water supply operation using the hot water supply circuit is started during the prevention operation, it is specified that the circulation path of the circulation heating circuit is switched to the bypass circulation path by switching the bypass switching means. .
[0021]
  This claim3According to the above, if the temperature condition for which freezing is expected is established, only the recirculation circuit, only the heating circuit, or the recirculation circuit and the heating circuit are selectively switched by the switching unit for heating by the antifreezing unit. Both are selected to communicate with each other, and in this state, the circulation pump is forcibly operated to start the freeze prevention operation for the circuit selected above. If the hot water supply operation is started during the freeze prevention operation, the bypass switching means is switched and the circulation path of the circulation heating circuit is switched to the bypass circulation path. Circulating water in the circuit is circulated between the circulation supply destination through the bypass pipe without passing through the heating can body of one can and two circuits. Therefore, even if the heating circulation path before switching the circulation path is heated by the common heating source in the heating can body, the circulation heating circuit and the hot water supply circuit are both heated by the common heating source. Heat from the heating can body is not transferred to the circulating water circulating in the circulation path, and the circulation heating circuit is thermally cut off from the hot water supply circuit side heated by the heating can body during the hot water supply operation. Will be. As a result, in the case where the freeze prevention operation is performed for the recirculation circuit, the risk of boiling of hot water in the bathtub can be surely avoided, while the freeze prevention operation is performed for the heating circuit. In this case, it is possible to reliably avoid the supply of high-temperature hot water to the heating terminal. In addition, even when any circuit is selected, it is possible to avoid supplying hot water to the switching means for heating.
[0022]
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[0023]
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[0024]
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[0025]
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[0026]
【The invention's effect】
  As described above, claim 1According to the hot water heater with an anti-freezing function according to the present invention, the hot water supply operation is started while the anti-freezing operation is being performed on the circulating heating circuit by the forced operation of the circulation pump, and the heating in the 1-can 2-circuit heating can body is performed. Even if the heating by the source is started, heat transfer from the heating can body to the circulating water in the circulating heating circuit can be prevented by thermal disconnection from the hot water supply circuit side. For this reason, even if the operation of the circulation pump based on the freeze-preventing operation is continued, heating of the circulating water circulating in the circulation heating circuit is avoided, and the circulation supply destination of the circulation heating circuit is unexpected. It is possible to reliably avoid the supply of high-temperature circulating water.
[0027]
  Claim2According to the hot water heater with an anti-freezing function according to the present invention, the hot water supply operation is started while the anti-freezing operation is being performed on the circulating heating circuit by the forced operation of the circulation pump, and the heating in the single can two circuit heating can body is performed. Even if the heating by the source is started, the bypass switching means is switched and the circulation path of the circulation heating circuit is switched to the bypass circulation path, so that the thermal shutdown of the circulating water in the circulation heating circuit from the hot water supply circuit side is prevented. This can be performed reliably, and the transfer of heat from the heated can body to the circulating water can be prevented. For this reason, even if the hot water supply operation is temporarily performed during the freeze prevention operation, unexpectedly high temperature circulating water can be reliably prevented from being supplied to the circulation supply destination of the circulation heating circuit. .
[0028]
  Claim3According to the hot water heater with anti-freezing function according to the present invention, only the recirculation circuit, only the heating circuit, or both the recirculation circuit and the heating circuit are circulated by selective switching of the heating switching means by the anti-freezing means. The freeze prevention operation by the forced operation of the pump can be performed. On the other hand, even if the hot water supply operation is started while the freeze prevention operation is being performed and the heating by the heating source in the single can / two-circuit heating can body is started, the bypass switching means is switched and circulated. Since the circulation path of the heating circuit is switched to a bypass circuit, the claim2Similarly to the above, it is possible to reliably perform the thermal cutoff of the circulating water in the circulating heating circuit from the hot water supply circuit side, and to prevent the transfer of heat from the heating can body to the circulating water. For this reason, even if the hot water supply operation is temporarily performed during the freeze prevention operation, unexpectedly high temperature circulating water can be reliably prevented from being supplied to the circulation supply destination of the circulation heating circuit. . ThisFreezingWhen the target of the anti-settling operation is a recirculation circuit, the risk of boiling of hot water in the bathtub can be reliably avoided, while when the target is a heating circuit, the heating terminal is hot. It is possible to reliably avoid the supply of hot water. In addition, the supply of high-temperature water to the heating switching means can be avoided when any circuit is selected.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0030]
  FIG. 1 shows the present invention.FreezingThe water heater used as the premise of the below-mentioned 1st Embodiment and 2nd Embodiment to which the water heater with a tie prevention function is applied is shown. This hot water supply device has a hot water supply function by a hot water supply circuit 2, a reheating circulation function by a reheating circulation circuit 3, and a hot water circulation type by a heating circuit 5 provided to the reheating circulation circuit 3 via a hot water branching unit 4. In the combustion can body 6 as a heating can body, the first heat exchanger 12 of the hot water supply circuit 2 and the second heat exchanger 32 of the recirculation circuit 3 are both in one heating can body. It is configured in a single can two-circuit type that is heated by heat exchange with the combustion heat of one combustion burner 7 as a common heating source. And the heating circuit 5 which shared the reheating circulation circuit 3 and the 2nd heat exchanger 32 comprises the circulation heating circuit of this invention.
[0031]
  The hot water supply circuit 2 is connected to a water pipe and is connected to a water inlet pipe 11 for entering the first heat exchanger 12, a hot water outlet pipe 13 for discharging hot water heated by the first heat exchanger 12, A bypass pipe 14 for mixing tap water with the hot water of the hot water pipe 13 is provided. The hot water supply pipe 16 is connected to a general hot water supply pipe 16 connected to the currant 15 and the like, while a hot water supply pipe 81 of a bath pouring circuit 8 for pouring hot water into the bathtub B and filling it is branched and connected. Yes. The water inlet pipe 11 is provided with a water inlet thermistor 17 for detecting the water inlet temperature and a water inlet flow rate sensor 18, while the hot water outlet pipe 13 has a hot water outlet at a position upstream of the joining position with the downstream end of the bypass pipe 14. A hot water thermistor 19 for detecting temperature is provided, and a hot water supply amount control valve 20 and a hot water supply thermistor 21 are provided at a position downstream of the joining position. The bypass pipe 14 is provided with a proportional valve 22. In the figure, reference numeral 10 denotes an F-point thermistor, and the F-point thermistor 10 detects the outside air temperature in the vicinity of the water heater.
[0032]
  The recirculation circuit 3 includes a return pipe 33 that returns hot water in the bathtub B to the second heat exchanger 32 by the operation of the circulation pump 31, and hot water heated by the second heat exchanger 32. Is provided to the bathtub B and a bypass pipe 35 that bypasses the second heat exchanger 32. The circulation pump 31, the return pipe 33, and the forward pipe 34 are used for reheating while circulating hot water between the bathtub B and the second heat exchanger 32. On the other hand, the bypass pipe 35 is branched at an upstream end by a three-way switching valve 36 as a bypass switching means interposed at a position of the return pipe 33 on the second heat exchanger 32 side, and a downstream end is the forward pipe 34. The second heat exchanger 32 is in communication with the downstream side position. In the case of a normal reheating operation or a heating operation described later, the three-way switching valve 36 is in a state in which the bypass pipe 35 side is shut off and the upper and downstream return pipes 33 are in communication with each other. In the state, switching control is performed by a controller 9 described later.
[0033]
  The return pipe 33 includes a water level detection sensor 37 and a water flow switch 38 for detecting the water level in the bathtub B by pressure detection in addition to the circulation pump 31 at a position upstream of the three-way switching valve 36 (tub B side). A bath water thermistor 39 for detecting the hot water temperature in the bathtub B is provided. Further, a temperature sensor 40 is interposed in the forward pipe 34 at a position immediately downstream of the communication position with the bypass pipe 35, and the heated circulating water heated by the second heat exchanger 32 by the temperature sensor 40. Alternatively, each temperature of the bypass circulating water circulated through the bypass pipe 35 is detected and output to the controller 9.
[0034]
  In addition, the bath pouring circuit 8 will be described. The bath pouring circuit 8 pours water into both the return pipe 33 and the forward pipe 34 to feed the hot water to the bathtub B into both the return pipe 33 and the forward pipe 34. It is designed to be carried out by both conveying methods. That is, the pouring pipe 81 branched from the pouring pipe 13 is provided with a pouring flow rate sensor 82, the downstream side is branched into two branch pouring pipes 83, 84, and one branch pouring pipe 83. The downstream end of the return pipe 33 communicates with the position immediately upstream of the three-way switching valve 36, and the downstream end of the other branch pouring pipe 84 communicates with the downstream position of the temperature sensor 40 of the forward pipe 34. . Each of the branched pouring pipes 83 and 84 is provided with a pouring control valve 85 and a pair of check valves 86, respectively.
[0035]
  The heating circuit 5 supplies hot water flowing in the circulation circuit 3 through the hot water branching unit 4 to the heating radiator 52 as a circulation supply destination built in the bathroom heating unit 51 as a heating terminal installed in the bathroom. The water is branched and the hot water is circulated and supplied as a circulation medium. The hot water branching unit 4 includes two three-way switching valves 41 and 42 serving as heating switching means, an air separator 43, and a predetermined pipe. By connecting the heating radiator 52 to the pipe, A heating circuit 5 is formed.
[0036]
  That is, the first three-way switching valve 41 is connected in the middle of the forward pipe 34 of the recirculation circuit 3, and the hot water supplied by the forward pipe 34 is branched and led to the heating radiator 52 through the heating forward pipe 53. It is like that. The hot water radiated in the heating radiator 52 is returned from the intermediate position in the vertical direction to the air separator 43 through the heating return pipe 54, and then the three-way switching valves 41 and 42 are selected from the air separator 43. Depending on the target switching state, it is returned to the return pipe 33 or the forward pipe 34 of the recirculation circuit 3 through either the first or second branch return pipe 55 or 56. That is, when the heating operation described later is stopped and the heating operation is performed, the return pipe 33 is connected to the return pipe 33 through the first branch return pipe 55 and the second three-way switching valve 42 connected to the bottom surface position of the air separator 43. When both the reheating operation and the heating operation are performed, the hot water overflowing through the second branch return pipe 56 connected to the top surface position of the air separator 43 is switched to the first three-way switch with respect to the forward pipe 34. The valve 41 is returned to a downstream position (tub B side position). In the figure, reference numeral 57 denotes a heating thermistor provided in the heating forward pipe 53, and the temperature of hot water circulatingly supplied to the heating radiator 52 is detected by the heating thermistor 57. In the figure, reference numeral 58 denotes a dryer thermistor provided in the bathroom heating unit 51. The dryer thermistor 58 detects the temperature of the outside air blown to the heating radiator 52.
[0037]
  Here, the return pipe 33 of the recirculation circuit 3 is configured such that the return pipe upstream part 33a from the bathtub B to the second three-way switching valve 42, the return pipe intermediate part 33b from the second three-way switching valve 42 to the three-way switching valve 36, From the three-way switching valve 36 to the second heat exchanger 32, the return pipe downstream portion 33c is named and divided. Similarly, the forward pipe 34 is connected to the upstream pipe 34a from the second heat exchanger 32 to the communication position with the bypass pipe 35, and from the communication position to the first three-way switching valve 41, the forward middle pipe section 34b. From the first three-way switching valve 41 to the bathtub B, the forward pipe downstream portion 34c is named and divided.
[0038]
  Then, when the reheating operation is stopped and both the first and second three-way switching valves 41 and 42 of the hot water branching unit 4 are switched to the heating-side switching state, that is, the first three-way switching valve 41 is downstream of the outgoing pipe. The side 34c side is shut off to connect the forward pipe middle stream part 34b to the heating forward pipe 53, and the second three-way switching valve 42 shuts off the return pipe upstream part 33a side to return the return pipe middle stream part 33b to the first branch. In the state where it is communicated with the return pipe 55, the heating circuit 5 has the following two circulation paths of the heating circulation path X and the bypass circulation path Y.
[0039]
  That is, when the three-way switching valve 36 is switched to the can body side switching state in which the bypass pipe 35 side is shut off and the return pipe midstream portion 33b and the return pipe downstream portion 33c are communicated, the heating circulation path X is formed. become. In this heating circuit X, the hot water heated by the second heat exchanger 32 passes to the heating radiator 52 through the forward pipe upstream portion 34a, the forward pipe middle flow portion 34b, the first three-way switching valve 41, and the heating forward pipe 53. The hot water after flowing and radiating heat from the heating radiator 52 is the heating return pipe 54, the air separator 43, the first branch return pipe 55, the second three-way switching valve 42, the return pipe midstream portion 33b, and the three-way switching valve 36. And it becomes a circulation path of returning to the 2nd heat exchanger again through the return pipe downstream part 33c, and being heated (refer the solid line arrow of Drawing 1). That is, the hot water heated by the second heat exchanger 32 is circulated and supplied as a circulation medium to the heating radiator 52 that is a circulation supply destination.
[0040]
  On the contrary, when the three-way switching valve 36 is switched to the can body cutoff switching state in which the return pipe downstream portion 33c side is shut off and the return pipe midstream portion 33b and the bypass pipe 35 are communicated with each other, the bypass circulation path Y is formed. Will be. In this bypass circuit Y, the hot water radiated by the heating radiator 52 is the heating return pipe 54, the air separator 43, the first branch return pipe 55, the second three-way switching valve 42, the return pipe midstream portion 33b, The hot and cold water flowing into the bypass pipe 35 through the three-way switching valve 36 (see the one-dot chain line arrow in FIG. 1) and flowing into the bypass pipe 35 is the forward pipe intermediate flow section 34b, the first three-way switching valve 41, and the heating forward pipe 53. It becomes a circulation path through which it is again flowed to the heating radiator 52. That is, without passing through the second heat exchanger 32, the hot water in a thermally shut-off state that is not subjected to combustion heating by the combustion burner 7 is circulated as a circulation medium to the heating radiator 52 that is a circulation supply destination. Will be supplied.
[0041]
  The bypass pipe 35 and the three-way switching valve 36 constitute a thermal cutoff switching means.
[0042]
  When both the first and second three-way switching valves 41 and 42 are switched to the heating + bath-side switching state and both the reheating operation and the heating operation are performed, that is, the first three-way switching valve 41 is the forward pipe. The downstream side 34c side is shut off to connect the forward pipe middle flow part 34b to the heating forward pipe 53, and the second three-way switching valve 42 shuts off the first branch return pipe 55 to return the return pipe upstream part 33a and the return pipe. Even in the state in which the middle flow portion 33b is in communication, the two circulations of the heating circulation path X and the bypass circulation path Y are achieved by switching between the can body side switching state and the can body cutoff side switching state of the bypass three-way switching valve 36 as described above. Will have a path.
[0043]
  On the other hand, the combustion can body 6 is provided with a combustion burner 7 at the top so as to inject the flame downward, and the first and second heat exchangers 12 and 32 cross at the intermediate position in the vertical direction. In the lower part, a smoke exhaust cylinder 61 for exhausting the exhaust gas after heat exchange is opened.
[0044]
  The combustion burner 7 burns gaseous fuel or liquid fuel. In the present embodiment, a so-called return-type gun-type burner that burns liquid fuel such as petroleum is illustrated. The combustion burner 7 sprays and burns liquid fuel supplied by a fuel supply pipe 73 in which an electromagnetic opening / closing valve 71 and an electromagnetic supply pump 72 are interposed, and surplus fuel is connected to the electromagnetic opening / closing valve 71 through a return pipe 74. The fuel supply pipe 73 between the electromagnetic supply pump 72 and the electromagnetic supply pump 72 is returned.
[0045]
  The water heater with a recirculation function provided with a heating circuit is controlled by a controller 9 having an MPU, a memory, and the like. The controller 9 is connected to various remote controllers (remote controllers) (not shown). Thus, the user can input various commands and display the status. The controller 9 performs a hot water supply control unit 91 (see FIG. 2) for performing a hot water supply operation by the hot water supply circuit 2, a bath control unit 92 for performing a reheating operation by the recirculation circulation circuit 3, and a heating operation by the heating circuit 5. Various control units such as a heating control unit 93 and a freeze prevention control unit 94 or 94 'as freeze prevention means for performing the freeze prevention operation are provided.
[0046]
  In the hot water supply control by the hot water supply control unit 91, the combustion opening of the combustion burner 7 is started when the user opens the currant 15 and the incoming water flow rate sensor 18 detects a flow rate equal to or higher than the minimum working water amount. First, based on information such as the incoming water temperature from the incoming water thermistor 17, the incoming water flow rate from the incoming water flow rate sensor, and the set hot water temperature input and set in the remote controller, the combustion operation is performed with a predetermined required combustion amount. Combustion control is performed based on the detected temperature from the hot water supply thermistor 21, and hot water at the set hot water temperature is discharged from the currant 15. Then, when the user closes the currant 15 and the water volume sensor 18 detects a flow rate lower than the minimum working water volume, the combustion of the combustion burner 7 is stopped.
[0047]
  The bath control unit 92 performs pouring control and reheating control. In the pouring control, for example, when a user inputs a pouring instruction for filling the bathtub B to the remote controller, the pouring control is performed. The valves 85 and 85 are opened, and the combustion operation of the combustion burner 7 is started. As a result, hot water of a predetermined temperature heated by the first heat exchanger 12 is supplied to the return pipe 33 and the forward pipe 34 through the hot water pipe 13 and the hot water pipes 81, 83, 84 and poured into the bathtub B. It will be. The pouring amount at this time is detected by the pouring flow rate sensor 82, and the pouring control is ended by detecting the predetermined water level as the bathtub water level of the bathtub B by the water level sensor 37. In this pouring control, both the three-way switching valves 41 and 42 of the hot water branching unit 4 use the bath alone in which the heating circuit 5 side is shut off and both the return pipe 33 and the forward pipe 34 are communicated with the bathtub B side. The state is controlled to be switched.
[0048]
  Further, for example, when a reheating command is input to the remote controller, reheating control is performed. First, the circulation pump 31 is operated, and when the water flow switch 38 is turned on, the combustion operation of the combustion burner 7 is started. Will be. As a result, the hot water in the bathtub B returned through the return pipe 33 in the second heat exchanger 32 is repelled by receiving the heat of combustion from the combustion burner 7, and the reheated hot water is passed through the forward pipe 34 to the bathtub. Supplied to B and circulated. And if the temperature of the hot water in the bathtub B becomes set temperature based on the detected temperature from the bath water thermistor 39, the combustion operation | movement of the said combustion burner 7 will be stopped.
[0049]
  Further, for example, when a heating operation command is input to the remote controller, the operation state is determined. When the heating operation is performed independently, first, both the first and second three-way switching valves 41 of the hot water branching unit 4 are used. , 42 are switched to the heating side switching state, and the three-way switching valve 36 is switched to the above-described can side switching state to form the heating circuit X. Next, the circulation pump 31 is operated and the combustion operation of the combustion burner 7 is started. Thereby, hot water is circulated between the heating radiator 52 while being heated by the second heat exchanger 32, and the heat of the hot water at a predetermined temperature (for example, 60 ° C.) is radiated by the heating radiator 52 to be inside the bathroom. Will be heated.
[0050]
  The above-mentioned common premise configuration includes the following first and second embodiments in anti-freezing control.
[0051]
<First Embodiment>
  As shown in FIG. 3, the freeze prevention control unit 94 according to the first embodiment first confirms that both the heating operation and the bath operation are stopped (steps S <b> 1 and S <b> 2), and then the F point thermistor 10 removes the outside. It is determined whether or not the temperature has decreased to the freeze prevention temperature for starting the freeze prevention operation (step S3). When the outside air temperature has decreased to the freezing prevention temperature (“YES” in step S3), and even if the outside air temperature has not dropped to the freezing prevention temperature, the staying water in the heating circuit 5 is prevented from freezing by the heating thermistor 57. When the temperature is lowered to the freezing prevention temperature for starting the operation (“NO” in step S3 and “YES” in step S4), the following antifreezing operation is started.
[0052]
  That is, it is confirmed that the hot water supply operation is stopped (“YES” in step S5), and then the circulation pump 31 is forcibly operated to determine circulation (steps S6 and S7). At this time, the bypass three-way switching valve 36 is controlled to be switched to the can side, and the heating three-way switching valves 41 and 42 are switched to the bath single use state. If the water amount switch 38 is turned ON continuously for a predetermined time (about 60 seconds) in the above-described circulation determination, it is determined that there is residual water at a predetermined water level in the bathtub B, and the freeze prevention operation is performed by the heating circuit 5 and the recirculation circuit 3. The heating three-way switching valves 41 and 42 are switched to the heating + bath-side switching state ("YES" in step S7, S8) in order to perform both. On the other hand, if the water amount switch 38 is not turned ON continuously for a predetermined time in the circulation determination, it is determined that there is no remaining water at a predetermined water level in the bathtub B, and the three-way heating is performed so that the freeze prevention operation is performed only for the heating circuit 5. The switching valves 41 and 42 are switched to the heating side switching state ("NO" in step S7, S9). In either case, the circulation pump 31 is operated until the ON timer set time by the timer 95 (see FIG. 2) elapses and then stopped (steps S10 and S11). Then, the circulation pump 31 is stopped until the OFF timer set time by the timer 95 elapses, and then the process returns. The OFF timer setting time is set to be shorter as the temperature is lower, and when residual water is present in the bathtub B, it is set to be longer as the temperature of the residual water is higher.
[0053]
  When only the heating circuit 5 is selected by the above freeze prevention operation (step S9), only the bathroom heating unit 51 is selected through the heating circuit 5, or both the heating circuit 5 and the recirculation circuit 3 are selected. In the case (step S8), forced circulation based on the intermittent operation of the circulation pump 31 is intermittently performed on the bathroom heating unit 51 through the heating circuit 5 and the bathtub B through the recirculation circuit 3, respectively, and freezing occurs. Will be prevented.
[0054]
  On the other hand, when the hot water supply operation is started during the freeze prevention operation, the processes of steps S6 to S12 are omitted based on the output signal from the hot water supply control unit 91 in the determination of step S5, and the circulation pump 31 is used. Is forcibly left in the OFF state (“NO” in step S5). Thereby, even if the combustion burner 7 is started to combust with the start of the hot water supply operation and the second heat exchanger 32 is heated together with the first heat exchanger 12, the heated hot water heating unit 51 or the bathtub B side Circulation supply to the market will be prevented.
[0055]
  In the anti-freezing control described above, the outside air temperature is monitored by the F point thermistor 10 in step S3. However, the present invention is not limited to this. For example, the dryer thermistor 58 may be used instead.
[0056]
Second Embodiment
  In the freeze prevention control unit 94 ′ (see FIG. 2) in the second embodiment, as shown in FIG. 4, first, after confirming that both the heating operation and the bath operation are stopped (steps S21 and S22), The F point thermistor 10 determines whether or not the outside air temperature has decreased to the freeze prevention temperature for starting the freeze prevention operation (step S23). When the outside air temperature has decreased to the freezing prevention temperature (“YES” in step S23), and even if the outside air temperature has not dropped to the freezing prevention temperature, the staying water in the heating circuit 5 is prevented from freezing by the heating thermistor 57. When the temperature is lowered to the freeze prevention temperature for starting the operation (“NO” in step S23 and “YES” in step S24), the following freeze prevention operation is started. The above start conditions are the same as in the first embodiment.
[0057]
  First, it is confirmed that the hot water supply operation is stopped ("YES" in step S25), and then the bypass three-way switching valve 36 is switched to the can body side switching state (step S26), and then the circulation pump 31 is forcedly operated. Then, circulation determination is performed (steps S27 and S28). At this time, the three-way switching valves 41 and 42 for heating are controlled to be switched to the bath single use state. The circulation determination is performed in the same manner as the circulation determination in the first embodiment (step S7 in FIG. 3). When there is residual water at a predetermined water level in the bathtub B, the anti-freezing operation is performed in the heating circuit 5 and the recirculation circuit 3 The three-way switching valves 41 and 42 for heating are switched to the above heating + bath side switching state ("YES" in step S28, S29). On the other hand, if there is no remaining water at a predetermined water level in the bathtub B in the circulation determination, the heating three-way switching valves 41 and 42 are switched to the heating side switching state so as to perform the freeze prevention operation only on the heating circuit 5 (step “NO” in S28, S30). In any case, each process (steps S31 to S33) in which the circulation pump 31 is operated for a predetermined time and then stopped for a predetermined time and then returned in a stopped state after the intermittent operation is performed. It carries out similarly to step S10-S12 (refer FIG. 3) of embodiment.
[0058]
  When only the heating circuit 5 is selected by the above anti-freezing operation as in the first embodiment (step S30), only the bathroom heating unit 51 through the heating circuit 5 or the heating circuit 5 and reheating When both of the circulation circuits 3 are selected (step S29), forced circulation based on the intermittent operation of the circulation pump 31 is performed on the bathroom heating unit 51 through the heating circuit 5 and the bathtub B through the recirculation circuit 3, respectively. It is performed intermittently to prevent freezing.
[0059]
On the other hand, when the hot water supply operation is started during the above freeze prevention operation, the start of the hot water supply operation is detected based on the output signal from the hot water supply control unit 91 in the determination of the above step S25. The switching valve 36 is controlled to be switched to the can cutoff switching state ("NO" in step S25, S34). And each process (steps S27-S33) of ON operation of the circulation pump 31, circulation determination, switching control of the three-way switching 41, 42 for heating, and intermittent operation of the circulation pump 31 (steps S27 to S33) is when the hot water supply operation is stopped (steps). Same as “YES” in S25). In this case, the circulation path is switched to the bypass circulation path Y by switching the bypass three-way switching valve 36 to the can body cutoff switching state, and the combustion burner 7 is started to combust even when the hot water supply operation is started. Even if the second heat exchanger 32 is heated together with the heat exchanger 12, the circulating water flowing through the bypass circulation path Y is not heated and is intermittently forcedly circulated under the same conditions as before.
[0060]
  In the first or second embodiment, the hot water heater having the bath function and the heating function has been described. However, the water heater having only the bath function without the heating circuit 5 or the heating without the circulation piping to the bathtub B is provided. The present invention may be applied to a water heater having only a function. Of course, you may apply this invention with respect to the water heater to which functions other than said heating function and bath function were added.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing first and second embodiments of the present invention.
FIG. 2 is a block configuration diagram of a controller according to the first and second embodiments.
FIG. 3 is a flowchart showing control contents of a freeze prevention control unit according to the first embodiment.
FIG. 4 is a flowchart showing control contents of a freeze prevention control unit according to a second embodiment.
[Explanation of symbols]
2 Hot water supply circuit
3 Recirculation circuit (circulation heating circuit)
5 Heating circuit (circulation heating circuit)
6 Heat exchange can (heated can)
7 Combustion burner (heating source)
31 Circulation pump
35 Bypass pipe (thermal cutoff switching means)
36 Three-way switching valve (switching means for bypass, switching means for thermal cutoff)
41, 42 Three-way switching valve (heating switching means)
51 Heating unit (heating terminal)
94, 94 'Freezing prevention control part (freezing prevention control means)
Y bypass circuit

Claims

A one-and-two-circuit heating can body configured such that a circulation heating circuit and a hot water supply circuit provided with a circulation pump are heated by a common heating source, and the circulation pump for preventing freezing of the circulation heating circuit. In a water heater with an anti-freezing function provided with anti-freezing means for performing anti-freezing operation to operate and forcibly circulate hot water in the circulation heating circuit,
Comprising a thermal cutoff switching means for switching the circulating heating circuit so as to be thermally cut off from the hot water supply circuit side, and preventing transfer of heat from the heating can body to the circulating water in the circulating heating circuit;
When the hot water supply operation using the hot water supply circuit is started during the execution of the freeze prevention operation, the anti-freezing means thermally shuts off the circulating heating circuit from the hot water supply circuit side by the thermal cutoff switching means. A water heater with a freeze prevention function, characterized by being configured to switch to a state.

A one-and-two-circuit heating can body configured such that a circulation heating circuit and a hot water supply circuit provided with a circulation pump are heated by a common heating source, and the circulation pump for preventing freezing of the circulation heating circuit. In a water heater with an anti-freezing function provided with anti-freezing means for performing anti-freezing operation to operate and forcibly circulate hot water in the circulation heating circuit,
The circulation heating circuit includes a bypass pipe that bypasses the heating can body by connecting the forward pipe and the return pipe constituting the circulation heating circuit, and a heating path that passes through the circulation path of the circulation heating circuit via the heating can body. A bypass switching means for bypassing the circulation path and the heating can body and switching to either one of the bypass circulation paths via the bypass pipe;
The freeze prevention means switches the circulation path of the circulation heating circuit to the bypass circulation path by switching the bypass switching means when the hot water supply operation using the hot water supply circuit is started during the execution of the freeze prevention operation. It is comprised so that the water heater with a freeze prevention function characterized by the above-mentioned.

A one-and-two-circuit heating can body configured such that a circulation heating circuit and a hot water supply circuit provided with a circulation pump are heated by a common heating source, and the circulation pump for preventing freezing of the circulation heating circuit. In a water heater with an anti-freezing function provided with anti-freezing means for performing anti-freezing operation to operate and forcibly circulate hot water in the circulation heating circuit,
The circulation heating circuit includes a recirculation circuit that connects the heating can body and the bathtub so as to be circulated by the operation of a circulation pump, and the circulation circuit is branched from the middle of the recirculation circulation circuit via a heating switching unit. A heating circuit that circulates between the heating can body and the heating terminal by the operation of a pump; and a forward pipe and a return pipe that constitute the recirculation circuit at a position closer to the heating can body than the switching means for heating. A bypass pipe that connects to each other and bypasses the heating can body, a heating circulation path that passes through the heating can body through the circulation path of the circulation heating circuit, and a bypass circulation that bypasses the heating can body and passes through the bypass pipe A bypass switching means for switching to either one of the roads,
The anti-freezing means is configured to selectively execute anti-freezing operation for one or both of the recirculation circuit and the heating circuit by selective switching of the heating switching means, and the anti-freezing thereof When the hot water supply operation using the hot water supply circuit is started during the operation, the circulation heating circuit is configured to switch the circulation path of the circulation heating circuit to the bypass circulation path by switching the bypass switching means. Water heater with anti-freezing function.