INSTANT WATER HEATER WITH A HOUSING

Description

[0001] The present invention relates to a continuous flow heater with a housing.

[0002] Known electric instantaneous water heaters of this type typically feature a housing for mounting the components within the instantaneous water heater, such as a duct arrangement with one or more heating channels, the control and power electronics, and, if applicable, the display and operating elements. Furthermore, the housing serves to mount the instantaneous water heater, for example, for wall mounting, and often also serves to spatially separate certain areas within the instantaneous water heater.

[0003] The housing of such instantaneous water heaters is manufactured, for example, as a plastic injection-molded part, which has sufficient strength and electrical insulation properties. Typically, the housing of this type of instantaneous water heater comprises at least a lower housing section and a housing cover. Individual parts may be manufactured from separate plastic injection-molded parts that are subsequently assembled into a complete housing. Typically, all hydraulic and power electronic components are located on the lower housing sections, while the housing cover serves to electrically insulate the interior of the device, as protection against splash and jet water, and for arranging and / or protecting operating and display devices.Over the lifetime of instantaneous water heaters, these housings are usually opened regularly, for example to carry out maintenance and / or repair work on the instantaneous water heater or the components installed therein.

[0004] Instantaneous water heaters with a housing are well known; for example, document DE 29721815 U1 describes a housing for an electric instantaneous water heater. The instantaneous water heater features a specially molded component of the cover and base support, which eliminates the need for additional fastening aids.

[0005] In addition, EP 2 641 030 B1 discloses a housing for an electric instantaneous water heater with a mounting frame for accommodating at least one heating block and internal piping for supplying cold water to the heating block and for withdrawing hot water from the heating block.

[0006] From CN201238417 Y, an electronic component, in particular a printed circuit board mounting structure, is known, comprising a carrier and a printed circuit board. The carrier is provided with a holding tank used to hold the printed circuit board, and an elastic hook is arranged on the side wall of the holding tank.

[0007] WO2018129826 A1 discloses a device for fastening a printed circuit board, comprising a front limiting part, a rear limiting part, an elastic snap fastener, and a placement slot. When the printed circuit board is placed in the placement slot, a notch of the printed circuit board passes through the front limiting part, so that the printed circuit board presses against the elastic snap fastener and the elastic snap fastener is deformed. When the printed circuit board moves away from the elastic snap fastener until the elastic snap fastener is released from the deformation, the front limiting part and the rear limiting part press against the printed circuit board, and the elastic snap fastener presses against the printed circuit board.When designing the housings for instantaneous water heaters, a variety of technical requirements must be taken into account, such as the placement and arrangement of the heating block, the position of hydraulic and electrical lines, insulation and EMC aspects, as well as the possibility of installing the instantaneous water heater in different installation situations at the site of use.

[0008] Modern instantaneous water heaters increasingly feature a multitude of control electronic components, which, in addition to circuits for complex control tasks, also include electronic circuits for operation, such as for the integration of touch displays, voice control or interfaces for wireless communication. A large number of electronic components are generally required to implement these functions. Such circuits are regularly designed as printed circuits, with the components arranged on circuit boards. Despite the degree of miniaturization already achieved, for example through the use of SMD components, numerous electronic components are often required for which miniaturization is not possible or only possible to a limited extent. Components for three-phase or mains voltage operation, in particular, are comparatively large due to the required insulation distances.Capacitors, especially electrolytic capacitors, also require more space. Inductive components such as coils, transformers, and others also have correspondingly large dimensions.

[0009] To ensure the simplest and most cost-effective assembly possible, the circuit boards of such printed circuits are often removably attached to the housing using snap-on elements.

[0010] A disadvantage is that the known instantaneous water heaters do not allow for the attachment of printed circuit boards with correspondingly large components, in particular, they do not allow for simple and reliable attachment of the printed circuit board to the device housing without screwing. In particular, printed circuit boards with large components, which have correspondingly large geometric dimensions and a comparatively high weight, cannot be adequately mechanically secured with the known snap-in elements. Furthermore, in the often expedient overhead mounting of the printed circuit boards, where the component side is arranged facing the housing base, the snap-in elements must be designed accordingly long due to the high height of the aforementioned components in order to support the printed circuit board at a distance from the housing base.As the overall length of the snap elements increases, their overall rigidity decreases, so that the desired reliable mechanical securing of the circuit board is no longer provided.

[0011] During the service life of an instantaneous water heater, it may be necessary to regularly replace, maintain, or renew individual components for reasons of product upgrade or, for example, in connection with defective components, especially after a power surge. Maintenance or repair work usually requires removing the circuit boards containing the electronic components or replacing them with replacement boards. Especially with raised circuit boards, which are located at the end of relatively long snap-in elements, damage to the snap-in elements can occur.

[0012] The object of the present invention is therefore to propose a continuous flow heater with a housing that allows for the simplest possible assembly and disassembly of the circuit boards while simultaneously ensuring their secure mechanical attachment to the housing. In particular, the object of the invention is to ensure the aforementioned arrangement and securing of the circuit boards even with raised circuit boards.

[0013] The object is achieved by the instantaneous water heater mentioned at the outset, comprising a housing with a housing lower part, wherein the housing lower part comprises a housing base, and wherein the housing base comprises at least two locking elements arranged at least substantially perpendicular to the housing base, each having a locking region and a locking region, wherein the locking elements are designed for the releasable arrangement of a circuit board comprising a soldering side and a component side, in that the circuit board can be arranged in a locking position at least in the locking region of the locking elements, wherein the instantaneous water heater further comprises a circuit board cover, wherein the circuit board cover covers the soldering side of the circuit board at least in some areas and locks the locking elements with the circuit board in the locking position in a locking state, in that the circuit board cover is designedto encompass the locking elements in the locking area to form a locking system.

[0014] The instantaneous water heater according to the invention has the advantage of always ensuring a mechanically secure arrangement of the circuit board in the housing of the instantaneous water heater, while at the same time ensuring the simplest possible handling during assembly and disassembly. Due to the arrangement of the circuit board in the locking position and the locking of the circuit board in a locked state by means of the circuit board cover, the circuit board is securely locked in the locking elements and is also secured and locked by the circuit board cover against unwanted loosening. Thanks to this double mechanical locking, the circuit board is not only attached to the housing via the locking elements, but the locking elements are also mechanically secured by means of the circuit board cover.In addition, the circuit board cover acts as a stiffening element, so that the locking elements form a unit with significantly increased mechanical rigidity when connected to the circuit board cover.

[0015] "Embrace" within the meaning of the invention represents the flat contact of the circuit board cover with the locking area of ​​the locking elements; alternatively, the term "embracing" in this context also refers to the contact of the locking area of ​​the locking elements by the circuit board cover, i.e., contact with one another or contact of the respective elements against one another.

[0016] A further advantage is that any forces acting on the circuit board are absorbed by the locking elements via the circuit board cover, so that only a minimal force can be introduced into the circuit board via the locking elements. This largely prevents mechanical stress on the circuit board carrier material and counteracts unwanted conductor breakage or interrupted contact with electronic components due to "cold solder joints." Due to the secure mechanical arrangement of the circuit board, mechanical vibration of the circuit board relative to the housing is also counteracted. This makes it particularly possible to securely arrange circuit boards with their component side facing the housing base and with comparatively high electronic components installed on the component side.The double securing of the circuit board by means of the aforementioned locking elements and the aforementioned circuit board cover enables reliable and releasable attachment of the circuit boards to the housing. A further advantage of locking the circuit board by means of the locking elements and the circuit board cover is that the material thickness of the elements can be significantly more delicate because fewer forces act on the elements, which in turn reduces the material used, resulting in a reduction in the amount of plastic used.

[0017] The soldering side and the component side within the meaning of the invention are the two flat sides of the circuit board. The soldering side predominantly contains the soldering points for electrically connecting the electronic components to the conductor tracks of the circuit board, at least for components where the connecting wires are inserted through drilled holes in the circuit board, whereas the component side predominantly contains the electronic components themselves. The component side primarily contains those electronic components with a correspondingly large overall height and therefore more space requirements. However, there is no strict conceptual separation between the soldering side and the component side in the circuit board of the instantaneous water heater according to the invention; this means that electronic components can certainly be arranged on the soldering side.soldered contacts on the component side, in particular surface-mounted electronic components, so-called SMD components, can be arranged on both the soldering and component side.

[0018] The locking elements are preferably designed in such a height that the circuit boards equipped with the electronic components can be locked into the locking area, and a sufficient distance is maintained between the electronic components and the housing base, creating a receiving space between the circuit board and the housing base. This distance between the circuit board and the housing base always ensures adequate cooling of heating components.

[0019] The locking elements are designed in such a way that the circuit board is locked into place during assembly. For this purpose, the circuit board can be pushed over the locking hooks of the locking elements during assembly, preferably with almost no force, and then positioned in the locking area. When the circuit board is arranged on the locking elements in the locking area, the circuit board is held in a locking position and thus mechanically fixed and secured against unwanted loosening. The height of the at least two locking elements can generally be varied, whereby the height depends in particular on the circuit board used and the maximum height of the electronic components. A large component height requires correspondingly long locking elements to enable the circuit board to be arranged between the locking elements. The height of the locking elements is preferably in the range between 3 cm and 15 cm.

[0020] Depending on the design of the instantaneous water heater's housing, the locking elements can preferably be integrated into at least one housing wall of the lower housing section if necessary. The locking elements are therefore not limited to being arranged as an individual element in the instantaneous water heater, but can also be designed as part of a larger housing element.

[0021] The locking area of ​​the locking elements is preferably designed such that the circuit board cover engages around the locking elements, forming a locking system. This means that at least a portion of the circuit board cover has a flat counter-surface designed to make contact in the locking area of ​​the locking elements. The locking area and the circuit board cover are preferably designed to correspond to one another in such a way that the counter-surface engages around the locking elements. Contact system refers to any contact of the circuit board cover with the locking area that leads to the formation of a mechanical connection between the locking elements and the circuit board cover for the additional fixation of both.

[0022] In a further advantageous embodiment of the invention, the housing base comprises at least three spaced-apart locking elements, each with one locking region and one locking region. This allows for influencing specific properties of the circuit board, for example, if the circuit board is large or contains large electronic components. In further advantageous embodiments, the housing base can also comprise more than three locking elements for locking or locking the circuit board, provided this is advantageous for additional mechanical securing of the circuit board.

[0023] A practical embodiment of the invention is characterized in that the locking elements have a side facing the circuit board and a side facing away from the circuit board, wherein the locking region is formed on the side facing the circuit board and the locking region is formed on the side facing away from the circuit board. The circuit board can be arranged between the sides of the locking elements facing the circuit board in the locking region. The circuit board cover is designed to engage around the locking elements on the side facing away from the circuit board in the locking region, forming the locking system. The locking elements preferably have a base body extending perpendicularly from the housing base and having flat sides.This base body, with the side facing the circuit board and the flat side facing away from the circuit board, enables reliable additional mechanical securing of the connection between the locking elements, the circuit board, and the circuit board cover. In other words, the locking elements are functionally designed on two sides, namely, on the one hand, they have a locking function and, on the other hand, they provide additional mechanical security for the locking elements once they have been locked in place by means of the circuit board cover. The flat side of the locking element facing away from the circuit board is advantageously provided with a flat surface to ensure flat contact with at least one area of ​​the circuit board cover, whereby the locking elements are additionally encompassed from the outside by means of the circuit board cover.This creates an easy-to-assemble and disassemble circuit board assembly that also provides mechanical security. At the same time, the circuit board cover protects the circuit board from direct mechanical impact, provides limited protection against splash water, and also provides electrically insulating contact protection, reliably protecting electronic components from damage caused by electrostatic charges.

[0024] According to a further preferred embodiment of the invention, the housing base comprises at least one positioning element for positioning the circuit board, which is arranged at least substantially perpendicular to the housing base and is designed for positive engagement in a positioning recess of the circuit board. The positioning element is preferably designed in the shape of a retaining pin. "At least substantially perpendicular" within the meaning of the invention means either perpendicular to the housing base or nearly perpendicular, i.e., with a deviation from the vertical of a maximum of ± 10°.The presence of the positioning element, which is arranged at least substantially perpendicular to the housing base, offers the possibility of additionally stabilizing the circuit board, as the positioning element is preferably positioned centrally. On the other hand, the positioning element assists in locking the circuit board in place by pre-positioning the circuit board at the desired installation height and orientation, and then locking it into its final position using the locking elements. The positioning element thus acts as a height stop for the circuit board.In a preferred embodiment, the positioning element is designed in steps in the longitudinal direction, i.e. the positioning element has different diameters, which preferably increase towards the housing base, depending on the size of a corresponding recess in the circuit board, in order to thereby define the desired positioning position on the respective step. Depending on the dimensions of the circuit board and the number, size, and mass of the individual electronic components, it may be advantageous to arrange more than one positioning element for positioning the circuit board running perpendicular to the housing base. Furthermore, it may be advantageous for the positioning element to have a hollow space. In this way, a high level of strength of the locking element is achieved with the lowest possible material consumption.

[0025] A further advantageous embodiment of the invention is characterized in that the lower housing part, particularly in the area of ​​the housing base with the locking elements, is formed in one piece. Particularly advantageously, the entire lower housing part is formed in one piece. A one-piece design of the lower housing part minimizes the assembly effort of the instantaneous water heater. In addition, the one-piece elements, for example, have better strength properties, which, among other things, increases the durability of the instantaneous water heater.

[0026] In a further advantageous embodiment of the invention, the locking elements each comprise at least two of the locking regions, wherein the at least two locking regions are spaced at different distances from the housing base. This offers the advantage that circuit boards can be locked into different locking positions at different heights starting from the housing base. As a result, only a single type of housing base needs to be designed and produced, in which circuit boards can be easily arranged at different heights, for example, if they contain electronic components of different dimensions. This reduces, among other things, the costs for injection molding tools, since one type of housing base can be used for a variety of different instantaneous water heater models.

[0027] A preferred development of the invention is characterized in that at least two of the locking elements are arranged on two sides of the circuit board. More preferably, at least two of the locking elements are arranged on opposite sides of the circuit board. If the two locking elements are arranged on opposite sides of the circuit board, an improved locking effect is achieved by arranging the circuit board between the two locking regions of the locking elements, since the locking elements on each of the opposite sides of the circuit board counteract each other as a spring element. The circuit board is thus locked in a form-fitting and / or force-fitting manner between the two locking elements that counteract each other with spring loading. More preferably, the at least two locking elements are arranged at least substantially opposite one another on an imaginary line connecting the two locking elements.In this way, the locking elements form opposing bearings for the circuit board, so that it is optimally fixed and secured between the locking elements.

[0028] According to a further preferred embodiment, the locking elements have a cross-section that tapers in the vertical direction starting from the housing base. Due to the cross-section of the locking elements tapering with increasing distance from the housing base, the circuit board arranged thereon is supported and mechanically secured with regard to its distance from the housing base. In this way, material is saved in the upper area of ​​the locking elements, thus minimizing the overall material expenditure for the locking elements, and sufficient space is provided for the arrangement of the circuit board and the circuit board cover. In addition, the rigidity of the locking elements in their upper area is reduced in a defined manner, thus realizing the desired spring effect for implementing the desired locking function of the locking elements.The material thickness of the locking elements, which increases towards the housing base, ensures the necessary mechanical stability of the locking elements at their locking element base, so that they are secured against bending from the housing base.

[0029] A further advantageous embodiment of the invention is characterized in that at least one of the locking elements has a hollow section, at least in part. The hollow section supports the rigidity of the locking elements while using as little material as possible and thus counteracts the tendency of the locking element to buckle. Preferably, the hollow section is designed such that the locking element is formed from two opposing and parallel webs. Further preferably, at least one side of the hollow section is open. The aforementioned configurations reduce the risk of buckling and increase the spring stiffness of the locking element.

[0030] A practical embodiment of the invention is characterized in that the circuit board cover releasably locks the locking elements with the circuit board in the locking position. Releasably locking the circuit board cover enables easy replacement or repair of the circuit board.

[0031] According to a further preferred embodiment of the invention, the circuit board cover comprises at least one holding element for releasably connecting the circuit board and / or at least one of the locking elements to the circuit board cover. This provides the option of releasably arranging the circuit board cover on the circuit board and / or on at least one of the locking elements, whereby, for example, maintenance and / or repair work can be carried out on the circuit board or circuit boards can be replaced with little effort. The holding element establishes a releasable mechanical connection between the circuit board cover and the circuit board and / or at least one of the locking elements, preferably via a locking lug and a receptacle for the locking lug, whereby the arrangement can take place either on the circuit board or on the circuit board cover.Particularly preferably, the holding element establishes a screwless mechanical connection between the circuit board cover and the circuit board and / or at least one of the locking elements.

[0032] A preferred development of the invention is characterized in that the locking area of ​​the locking elements is formed by a notch running at least substantially parallel to the housing base. "At least substantially parallel" in the sense of the invention means either parallel to the housing base or almost parallel, i.e., with a deviation from the housing base of a maximum of ± 10°. The presence of the notch running at least substantially parallel to the housing base offers the advantage that, on the one hand, the circuit board can be securely locked into the notch, and, on the other hand, its alignment takes place along the contours of the housing base, which, among other things, facilitates installation. The notch running parallel to the housing base is a deliberately chosen local material weakening, which can generally have different shapes, depths, etc., depending on the application, i.e., depending on the circuit board used.Further preferably, the notch is designed such that the circuit board can be arranged in a force-fitting manner in the notch at least in some areas.

[0033] A further advantageous embodiment of the invention is characterized in that the depth of the notch corresponds at least substantially to the thickness of the circuit board. This offers the advantage of ensuring that the circuit board is locked into the notch with a precise fit and is secured against slipping.

[0034] According to a further preferred embodiment, the circuit board cover comprises a circumferential edge which, in the locked state, encompasses the locking area of ​​the locking elements, forming the locking system. The circumferential edge is preferably formed as a flat element perpendicular to the circuit board cover. In an advantageous design, the circumferential edge can also be formed only partially around the circuit board cover. The circumferential edge offers the possibility of providing an element for engagement with the locking area through the simplest possible structural design, which reliably prevents accidental release of the locked circuit board.

[0035] A further advantageous embodiment of the invention is characterized in that the circuit board cover comprises through-openings that, when locked, encompass the locking area of ​​the locking elements, forming the locking system. By means of the through-openings, the locking elements offer a further simple and secure solution for preventing accidental release of the locked circuit board by locking the circuit board cover with a positive fit to the locking elements.

[0036] Further preferred and / or expedient features and embodiments of the invention emerge from the dependent claims and the description. Particularly preferred embodiments are explained in more detail with reference to the accompanying drawings. The drawing shows: Fig. 1 is a schematic cross-sectional view of a housing bottom part of an instantaneous water heater with a latched circuit board and a circuit board cover and Fig. 2 is a schematic perspective view of the housing bottom part of the instantaneous water heater.

[0037] Fig. 1 shows a schematic cross-sectional view of a housing bottom part 11 of the housing 10 of a continuous-flow heater according to the invention, not shown in full in the drawings. The housing bottom part 11 comprises a housing base 12 and at least two locking elements 13 arranged at least substantially perpendicular to the housing base 12. The locking elements 13 are thus arranged at least substantially orthogonally to the housing base 12. The locking elements 13 comprise a locking region 14 and a locking region 15 and are designed for detachable arrangement on a printed circuit board 16. The printed circuit board 16 comprises a soldering side 17 and a component side 18. Fig. 1 Electronic components 25 which have different heights are schematically arranged on the component side 17.

[0038] In the Fig. 1 is shown by way of example how the circuit board 16 is arranged in the locking region 14 of the locking elements 13 in a locking position. The locking elements 13 have a side facing the circuit board 16 and a side facing away from the circuit board 16. The locking region 14 is formed on the side facing the circuit board 16 and the locking region 15 is formed on the side facing away from the circuit board 16. To arrange the circuit board 16 in the locking position, the circuit board 16 is positioned in the locking region 14. The locking region 14 extends along the locking elements 13; the locking function is supported by a locking lug located in the locking region 14, under which the circuit board 16 can be arranged with the soldering side 17 and in this way is fixed to the housing base 11 mechanically securely and against unwanted loosening.

[0039] Fig. 1 further shows a circuit board cover 19, wherein the circuit board cover 19 covers the soldering side 17 of the circuit board 16 at least in part. The circuit board cover 19 locks the locking elements 13 with the circuit board 16 in the locking position in a locked state. The circuit board cover 19 is designed to engage around the locking elements 13 in the locking area 15, forming a locking system. The locking system is achieved by arranging the circuit board cover 19 in the locking area 15. In the Fig. 1 Both the area of ​​the circuit board cover 19 that rests against the locking area 15 and the actual locking area 15 are formed with a flat surface, which enables a high degree of fitting accuracy and precise locking of the locking elements 13.

[0040] Technically, the combination of locking the circuit board 16 and locking the locking elements 13 offers a number of advantages. Fig. 1 It can be seen that the circuit board 16 is held in position by the locking elements 13, which secures it against unwanted displacement. Due to the small contact surface that the peripheral edge of the circuit board 16 offers at the locking area 14 of the locking element 13, the circuit board 16 is only partially secured against unintentional release if one of the locking elements 13 moves. As soon as the circuit board 16 is released from a locking area 14 of a locking element 13, the other locking element 13 no longer offers the necessary stability to hold the circuit board 16 in position. On the one hand, the circuit board cover 19 at least partially protects the circuit board 16 from external factors such as splash water, and on the other hand, the circuit board cover 19 locks both locking elements 13.By locking both locking elements 13, any forces that may occur are distributed relative to one locking element 13 and absorbed by the circuit board cover 19 through the flat locking system. This prevents the circuit board 16 from becoming detached from the locking area 14 of the locking elements 13, as the encompassing circuit board cover 19 acts as an additional securing element.

[0041] Advantageously, the housing base 12 comprises a positioning element 20 arranged at least substantially perpendicular to the housing base 12 for positioning the circuit board 16, which is designed for positive engagement in a positioning recess 21 of the circuit board 16. The positioning element 20 is thus arranged at least substantially orthogonally to the housing base 12. The positioning element 21 is particularly preferably arranged in the center of the circuit board 16. However, the positioning element 20 and the positioning recess 21 are not mandatory components to ensure reliable locking and securing of the circuit board 16.

[0042] Fig. 2 shows a schematic perspective view of the housing base 11 of the instantaneous water heater without the circuit board 16 locked and secured with the circuit board cover 19. Fig. 1 and 2However, the advantageous arrangement of the locking elements 13 is clearly evident. The locking elements 13 are arranged on two sides of the circuit board 16. As can be seen from Fig. 2 As can be seen, the locking elements 13 are particularly advantageously arranged opposite one another.

[0043] The locking elements 13 and the positioning element 20 preferably have a cross-section that tapers vertically, starting from the housing base 12. The cross-section and / or the wall thickness of the elements decreases from the housing base 12 toward the opening of the housing lower part 11.

[0044] The side view of the Fig. 1 shows that the locking elements 13 have a hollow section 22, at least in some areas. Advantageously, the positioning element 20 also has a hollow section 22. The hollow section 22 depends on the size of the locking and positioning elements 13, 20 used and the required rigidity.

[0045] The circuit board cover 19 further preferably comprises at least one holding element - not shown in the drawings - for releasably connecting the circuit board 16 and / or at least one of the locking elements 13 to the circuit board cover 19. The holding element is formed, for example, by hooks, locking means or the like.

[0046] Advantageously, the locking region 14 of the locking elements 13 is formed by a notch 23 running at least substantially parallel to the housing base 12. The notch 23 can have different shapes. Fig. 1 and Fig. 2 The notches 23 are designed as elongated material weakenings into which the circuit board 16 can be arranged in the locking position or into which the edge of the circuit board 16 engages in a locking manner. For this purpose, the circuit board 16 is particularly advantageously arranged in the notch 23 in a force-fitting manner, at least in some areas.

[0047] As in the Fig. 1 As shown, the circuit board cover 19 comprises a circumferential edge 24, which, in the locked state, encompasses the locking region 15 of the locking elements 13, forming the locking system. The circumferential edge 24 preferably extends orthogonally to the circuit board cover 19 and forms a positive connection with the locking region 15.

[0048] Further preferably, the circuit board cover 19 comprises through openings - not shown in the drawings - which, in the locked state, encompass the locking area 15 of the locking elements 13 to form the locking system.

Claims

1. Continuous flow heater, comprising a housing (10) with a bottom housing part (11), wherein the bottom housing part (11) comprises a housing base (12), characterised in that the housing base (12) comprises at least two latching elements (13) with a latching region (14) and a locking region (15) arranged at least substantially perpendicular to the housing base (12), wherein the latching elements (13) are configured for the releasable arrangement of a printed circuit board (16) comprising a solder side (17) and a component side (18), in that the printed circuit board (16) is arrangeable in a latching position at least in the latching region (14) of the latching elements (13), a printed circuit board cover (19), wherein the printed circuit board cover (19) covers the solder side (17) of the printed circuit board (16) at least in some areas and locks the latching elements (13) with the printed circuit board (16) in the latching position in a locking state, in that the printed circuit board cover (19) is configured to embrace the latching elements (13) in the latching area (15), forming a locking contact.

2. Continuous flow heater according to claim 1, characterised in that the latching elements (13) comprise a side directed towards the printed circuit board (16) and a side directed away from the printed circuit board (16), wherein the latching region (14) is configured on the side directed towards the printed circuit board (16) and the locking region (15) is configured on the side directed away from the printed circuit board (16), and wherein the printed circuit board (16) is arrangeable in the latching region (14) between the sides of the latching elements (13) directed towards the printed circuit board (16) and the printed circuit board cover (19) is configured to embrace the latching elements (13) on the side directed away from the printed circuit board (16) in the latching region (15), forming the locking contact.

3. Continuous flow heater according to claim 1 or 2, characterised in that the housing base (12) comprises at least one positioning element (20) arranged at least substantially perpendicularly to the housing base (12) for positioning the printed circuit board (16), which is configured for positive engagement in a positioning recess (21) of the printed circuit board (16).

4. Continuous flow heater according to one of claims 1 to 3, characterised in that the bottom housing part (11), in particular in the region of the housing base (12) with the latching elements (13), is configured in one piece.

5. Continuous flow heater according to one of claims 1 to 4, characterised in that the latching elements (13) each comprise at least two of the latching regions (14), wherein the at least two latching regions (14) are spaced at different distances from the housing base (12).

6. Continuous flow heater according to one of claims 1 to 5, characterised in that at least two of the latching elements (13) are arranged on two sides of the printed circuit board (16).

7. Continuous flow heater according to claim 6, characterised in that at least two of the latching elements (13) are arranged on opposite sides of the printed circuit board (16).

8. Continuous flow heater according to one of claims 1 to 7, characterised in that the latching elements (13) have a vertically tapering cross-section extending from the housing base (12).

9. Continuous flow heater according to one of claims 1 to 8, characterised in that at least one of the latching elements (13) comprises at least partially a cavity section (22).

10. Continuous flow heater according to one of claims 1 to 9, characterised in that the printed circuit board cover (19) comprises at least one retaining element for releasably connecting the printed circuit board (16) and / or at least one of the latching elements (13) to the printed circuit board cover (19).

11. Continuous flow heater according to one of claims 1 to 10, characterised in that the latching region (14) of the latching elements (13) is formed by a notch (23) extending at least substantially parallel to the housing base (12).

12. Continuous flow heater according to claim 11, characterised in that the notch (23) is configured in such a way that the printed circuit board (16) is at least partially arrangeable in the notch (23) in a force-locking manner.

13. Continuous flow heater according to one of claims 11 or 12, characterised in that the depth of the notch (23) corresponds at least substantially to the thickness of the printed circuit board (16).

14. Continuous flow heater according to one of claims 1 to 13, characterised in that the circuit board cover (19) comprises a circumferential edge (24) which, in the locking state, embraces the locking region (15) of the latching elements (13) to form the locking contact.

15. Continuous flow heater according to one of claims 1 to 14, characterised in that the printed circuit board cover (19) comprises through-openings which, in the locking state, embrace the locking region (15) of the latching elements (13) to form the locking contact.