NL2007537C2 - HEATING DEVICE WITH TILTABLE HEAT EXCHANGER. - Google Patents

Abstract

The heating device comprises a housing 1, a burner 16 operationally connected to a heat exchanger 18 to heat a medium flowing through the heat exchanger, a base 34 and a movement means such as a horizontal hinge 36 that permits the heat exchanger to be moved between an operational position inside the housing and a maintenance position at least partially outside the housing. The base is fixed to the heat exchanger and, in the operational position, the base connects to the housing in a gas-tight manner to define a gas-tight space (42, figure 1) in which the heat exchanger and burner are located. In the maintenance position, cleaning of an inner side of the heat exchanger is possible. A support 48,52 may be provided on an inner side of the housing to receive the base in the operational position, the base resting on-top of the support. Ideally, the support makes a gas-tight seal with the housing and the base.

Description

P30782NL00 / RWY

Brief indication: Heater with tilting heat exchanger

The invention relates to a heating device according to the preamble of claim 1. Such a heating device is used for heating for a medium, such as water. The heated water is then used to heat spaces by passing the heated medium through one or more radiators.

5 Alternatively, or in addition, the heated water can be used by users as hot tap water.

DE-A1-101.30.925 discloses a heating device for heating water. The heating device comprises a housing, a burner and a heat exchanger.

In normal use, the burner is provided on top of the heat exchanger. The flames from the respective burner are directed downwards and transfer heat in the heat exchanger to water. The heating device further comprises a bottom. A condensate tray is fixed in the bottom. In the position of use, the heat exchanger rests in the condensate tray, with which it forms the bottom of the heat exchanger. The condensate tray is further connected to a flue gas outlet for discharging the flue gases that flow from the burner into the condensate tray via the heat exchanger. The heating device further comprises rotation means. For maintenance of the heat exchanger, it can be lifted from the condensate shell and rotated via the rotation means to a maintenance position outside the housing of the heating device. Thanks to this combined translation and rotation movement, it is possible to inspect and / or clean the heat exchanger from below.

A problem with the known heating device is that it is relatively complex mechanically.

It is an object of the present invention to provide a heating device that at least partially overcomes the aforementioned drawback, or to provide at least one alternative. In particular, it is an object of the present invention to provide a heating device that is simpler than that of the prior art.

The invention achieves the object by means of a heating device according to claim 1. Advantageous embodiments are defined in the dependent claims.

A heating device comprises a housing, a burner, a heat exchanger, a bottom and displacement means. The burner is operatively connected to the -2 heat exchanger for heating a medium that flows through the heat exchanger. The displacement means movably connect the heat exchanger to the housing to move between a position of use within the housing and a maintenance position at least partially outside the housing. In the position of use, the bottom connects in a gas-tight manner to the housing for limiting a gas-tight space within the housing, in which gas-tight space at least the burner and the heat exchanger are located. The heat exchanger is fixed on the bottom. The bottom is connected to the housing by means of the displacement means such that the heat exchanger and the bottom are jointly displaceable between the position of use and the maintenance position.

Thanks to the invention, the heat exchanger can move in a simple manner between the position of use and the maintenance position, without requiring a sequence of two different movements, such as the translation and rotation movement in the prior art.

In particular, the heating device further comprises a feed-through element which is gas-tight and fixedly connected to an inner side of the housing and comprises at least one feed-through hole for feeding a conduit to the gas-tight space, the bottom comprising a recess corresponding to the feed-through element, and the bottom in the position of use connects to the lead-through element for jointly delimiting the gas-tight space within the housing. As a result, a rigid conduit can be led to the gas-tight space, without this preventing the movability of the bottom.

In one embodiment, the heating device further comprises a support, which support is provided on an inner side of the housing and is adapted to receive the bottom in the position of use. Such a support makes a simple and reliable support of the movable bottom possible.

In particular, the lead-through element and the support are formed as one component. This reduces the number of points between the gas-tight space and the remaining space in the housing that must be gas-tightly sealed.

In one embodiment, the heat exchanger is provided on the bottom and the bottom in the position of use is supported on the support. The heat exchanger hereby rests on the support via the bottom, which facilitates both supporting and gas-tight sealing of the bottom with respect to the housing.

In an advantageous form, the support has only a force-transmitting connection with a front and / or rear of the housing. This makes a smooth side of the housing possible.

In one embodiment, the heating device further comprises a gas-tight support seal which extends between the support and the housing. Such a separate gas-tight support seal makes it possible to choose optimum materials for the gas-tight support seal and the support.

In an advantageous form, the heating device further comprises a gas-tight bottom seal which, in the position of use, extends between the support and the bottom. Such a separate gas-tight bottom seal makes it possible to choose optimum materials for the gas-tight bottom seal and the support.

In one embodiment, the displacement means comprise a hinge for tiltably connecting the bottom to the housing. Tilting around a hinge is a constructively simple way of making the bottom movable.

In particular, the hinge is provided on the front side of the housing and comprises a substantially horizontal hinge axis. As a result, the center of gravity of the bottom with heat exchanger moves upwards when bringing the heat exchanger to the maintenance position, and downwards when returning to the position of use. This makes a simple gas-tight support of the bottom in the housing possible.

The invention further relates to a method for maintaining a heating appliance according to the relevant independent claims. Such a method is a simple way to maintain the heating device, while a gas-tight space is created after the bottom is returned to the position of use with the heat exchanger.

The invention also relates to the following aspects, which are advantageous both in themselves and in combination with the above-mentioned aspects.

A heating device comprises a housing, a burner, a heat exchanger, and a hinge, the burner being operatively connected to the heat exchanger for heating a medium flowing through the heat exchanger, the housing comprising a housing opening on a front side of the heating device, - the hinge tiltably connects the heat exchanger to the housing and defines a substantially horizontal tilting axis to tilt the heat exchanger through the housing opening between a position of use within the housing and an assembly position at least partially outside the housing, the hinge being a hinge support and comprises a hinge pin with a diameter D, - the hinge support comprises a hinge hole with a minimum diameter D for rotatably supporting the hinge pin, and - the hinge support comprises a lead-in opening, which lead-in opening, in a plane perpendicular to the tilt axis, has width Bj that is larger than D and the hinges to interrupt a continuous connection for receiving the hinge pin in a direction perpendicular to the tilt axis and guiding the hinge pin to the hinge hole.

Thanks to the invention, the heating device can be assembled in a simple manner, because the heat exchanger can be hung in the housing in one go. Because hinge support and hinge pin are already present, no further fixing operations need to be carried out at the moment of hanging. Thanks to the invention, it is even possible to attach one or more components, such as the burner, fan, and / or pipes, to the heat exchanger before it is hung.

Movements, such as receiving and guiding the hinge pin, in directions perpendicular to the tilt axis are understood here to mean any displacement which takes place substantially completely in a plane perpendicular to the tilt axis. The direction of the displacement does not have to cross with the tilt axis and the displacements can take place along any type of line, including a straight or curved line. Importantly, there is no substantial component of the displacement in a direction parallel to the tilt axis.

Preferably, in a plane perpendicular to the tilting axis, the hinge hole has a length that is greater than Bi and the hinge hole, with the heat exchanger in the position of use, extends at least partially in a vertical direction in its longitudinal direction.

Preferably, in a plane perpendicular to the tilting axis and with the heat exchanger in the position of use, the hinge support completely limits the hinge hole at the location of the hinge pin in the horizontal direction. As a result, the hinge connection between the heat exchanger and housing, after the heat exchanger has been placed in the position of use, cannot come loose unintentionally.

In one embodiment, in a plane perpendicular to the tilting axis and with the heat exchanger in the assembly position, the hinge support completely limits the hinge hole at the location of the hinge pin in the horizontal direction. As a result, the hinge connection between the heat exchanger and housing, after the heat exchanger has been suspended in the assembly positions, cannot come loose unintentionally.

In an advantageous form, the inlet opening is directed towards the front of the heating device at the position of use of the heat exchanger. If the hinge support is provided on the housing, this means that the lead-in opening faces forward, so that the heat exchanger with hinge pin can be easily received. If the hinge support is provided on the heat exchanger, this means that the lead-in opening can be directed to the housing with hinge pin by hanging the heat exchanger in the housing in a tilted position, for example almost upside down.

In one embodiment, in a plane perpendicular to the tilt axis, the hinge hole has an elongated shape with a width B that is substantially equal to D and a length of at least twice D. means that the width B is just sufficient to accommodate the hinge pin movably, that is to say that the hinge pin can slide through the hinge hole in the longitudinal direction of the hinge hole and that the hinge pin can rotate about its longitudinal axis in the hinge hole. Thanks to the possibility of sliding, the hinge pin can slide in the hinge hole to a position that is remote from the lead-in opening.

In an advantageous form, in a plane perpendicular to the tilting axis, the lead-in opening forms the continuous connection substantially halfway through the pivot hole. As a result, the hinge support forms tabs on either side of the walk-in opening which bound the hinge hole at both ends thereof. These tabs ensure that the hinge pin and the hinge support do not inadvertently become detached from each other when the hinge pin is located at one end or the other end of the hinge hole.

In one embodiment, the hinge support is fixedly connected to the heat exchanger and the hinge pin is connected to the housing. As a result, the hinge support 15 rotates during tilting, as a result of which the orientation of the entrance opening also changes. Thus, the lead-in opening can be positioned in the hinge support so that it faces the hinge pin while the heat exchanger is being hung in, while the lead-in opening points downwards during the tilting of the heat exchanger, thereby reducing the risk of the hinge pin being removed from the hinge opening via the lead-in opening touch is minimal.

In an advantageous form, the heating device further comprises a bottom, which bottom in the position of use connects gas-tightly to the housing for bounding a gas-tight space within the housing, in which gas-tight space at least the burner and the heat exchanger are located, wherein the heat exchanger is fixedly provided on the bottom, and the bottom is connected to the housing by means of the hinge such that the heat exchanger and the bottom are jointly tiltable between the position of use and a maintenance position or the assembly position. As a result, the heat exchanger can move in a simple manner between the position of use and the maintenance position or assembly position, without the need for a sequence of two different movements.

In particular, the heating device further comprises a feed-through element which is gas-tight and fixedly connected to an inner side of the housing and comprises at least one feed-through hole for feeding a conduit to the gas-tight space, the bottom comprising a recess corresponding to the feed-through element, and the bottom in the position of use connects to the lead-through element for jointly defining the gas-tight space within the housing. As a result, a rigid conduit can be led to the gas-tight space, without this preventing the movability of the bottom.

In one embodiment, the heating device further comprises a jib that forms a connection between the housing and the heat exchanger for limiting the tiltability of the heat exchanger relative to the housing. As a result, the heat exchanger can easily be brought into the maintenance position, in which the heat exchanger can be easily cleaned.

The invention further relates to a method for assembling a heating device. The method comprises the following steps, performed in the indicated order: providing a housing, a burner, a heat exchanger, and a hinge, wherein the hinge comprises a hinge support with hinge hole and a hinge pin and defines a horizontal tilt axis, moving the heat exchanger toward the housing, in a direction perpendicular to the tilt axis, wherein the heat exchanger is in a tilted position relative to a position of use of the heat exchanger within the housing, during the last part of the perpendicular movement receiving the hinge hole from the hinge pin, tilting the heat exchanger around a hinge to a maintenance or service position.

This is a simple method of assembly because the heat exchanger is hung in the housing in one go. Because the hinge support receives the hinge pin during the last part of the displacement, no further fixing operations have to be carried out at the moment of suspension. Thanks to the invention, it is even possible to attach one or more components, such as the burner, fan, and / or pipes, to the heat exchanger before it is hung.

In an advantageous embodiment, the heat exchanger is tilted more than 90 ° and less than 180 ° during use with respect to the position of use. This makes it possible to hang the heat exchanger in a housing.

In a preferred embodiment, the hinge hole and the hinge pin move vertically relative to each other while receiving the hinge pin in the hinge hole. As a result, the hinge pin cannot, or at least not easily, come loose from the hinge hole during the following tilting movement.

In an advantageous form, during tilting the heat exchanger around the hinge, the hinge pin moves from a first end of the hinge hole to a second end of the hinge hole, which second end is opposite the first end. It is advantageous that the hinge pin in the first end cannot, or at least not easily, come loose from the hinge hole, and that the hinge pin can then also not, or at least not easily, come loose after tilting, because it then moves to the second end has been moved.

-7-

In a preferred embodiment, after tilting the heat exchanger around the hinge to the maintenance or use position, there is a step of arranging a jib between the housing and the heat exchanger. This boom ensures that the heat exchanger can then tilt easily and safely between the position of use and the maintenance position.

The invention will be further elucidated on the basis of an embodiment shown in the accompanying drawing, in which:

FIG. 1 shows a spatial view through a heating device according to the invention;

FIG. 2 shows a detail of a cross-section of the heating device according to the invention;

FIG. 3 shows the view of fig. 1, with the flue gas discharge removed;

FIG. 4 shows the view of fig. 1, with a heat block tilted to a maintenance position;

FIG. 5 shows the view of FIG. 4 with the burner and gas supply removed;

FIG. 6 shows the heating device according to FIG. 5 in a side view;

FIG. 7 shows the heating device according to FIG. 5 in a top view; FIG. 8 shows a detail of a hinge in the position of the heating device according to FIG. 5;

FIG. 9 shows a heating device with the heat block in an assembly position;

FIG. 10 shows the assembly position of FIG. 9 in side view;

FIG. 11 shows a hinge in the assembly position of FIG. 9; and FIG. 12 shows the hinge of FIG. 11 with the bolt removed.

FIG. 1 shows a heating device according to the invention which is indicated in its entirety by reference numeral 1. In this case, the heating device 1 is a wall-hung Central Heating Boiler, which is suspended from a wall on its rear side. The heating device 1 comprises a housing 2, which in this case is made from a set piece of metal sheet material. The housing 2 has a housing opening 3 on a front side of the heating device 1. The heating device 1 further comprises an air supply 4 for combustion air and a combustion gas supply line 6. The combustion gas supply line 6 comprises a first pipe part 8, a safety valve 10, and a gas hose 12 Air supply 4 and gas hose 12 both lead to a fan 14, where gas and air are mixed. An output of the fan 14 is connected to a burner 16 which, together with a heat exchanger 18, forms a heat block 20 (see Fig. 4).

On a lower side, the heat exchanger 18 is in continuous communication via a condensate collector 22 with a combustion gas outlet 24 (Fig. 1). The flue gas discharge pipe 24 is in continuous communication with a flue gas bend 26, which leads to a connection opening 28 which is provided in an upper side of the housing 2.

The connection 28 is a concentric double-walled connection of which an inner circular opening part 30 functions as a connection opening for flue gases 10 and an outer ring-shaped opening part is intended as combustion air supply opening 32.

The heating device 1 further comprises a bottom 34. The bottom, in this case a base plate 34, is gas-tightly connected to the housing 2 in the normal position of use of Figs. 1-3, as will be explained in more detail below with reference to Fig. 2, among others. explained. The heat exchanger 18 is provided on the bottom 34, in this exemplary embodiment via the condensate collector 22. The heating device 1 is further provided with displacement means, here in the form of a left hinge 36 and a right hinge 38. The hinge 36 comprises a left hinge support 39 and a hinge pin 40 which in this case is formed by a bolt mounted in one side of the housing 2. The hinge pin 40 has a diameter D at the location of the hinge support; the bolt head, of course, has a larger diameter than D. The longitudinal axis of the hinge pin 40 defines a tilt axis 41. The left hinge support 39 extends downwardly from the base plate 34 on its left front side. The right hinge 38 comprises parts similar to the left hinge 36. The left hinge 36 and right hinge 38 are located in the position of use as shown in Fig. 1 below the base plate 34 near a front edge of the base plate 34. The base plate 34 divides an inner space within the housing 2 in a gas-tight space 42 and an underlying open space 44.

The bearing gas-tight connection between the base plate 34 and the housing 2 is formed by a support, in this case a base plate support part 46 (see, inter alia, Fig. 6 and Fig. 9). The base plate support member 46 comprises a left support strip 48, a lead-through element, here in the form of a lead-through plate 50, a rear support strip 52, and a right support strip (not visible in the views shown). A detail section through the rear support strip 52 and the base plate 34 is shown in Fig. 2. The rear support strip 52 35 has an m-shaped cross section. The base plate support part 46 is integrally formed as an injection molded part from a plastic polymer, in this case a thermoplastic copolymer, in particular Acrylonitrile-Butadiene-Styrene (ABS). ABS is a form-retaining material that has a low tendency to creep. This makes it suitable as a support material. The rear support strip 52, and thereby also a substantial part of the entire base plate support 46, bears on a rear side of the housing 2 via indented parts 54 of a rear wall of the housing 2. At the front side, the base plate support 46 is connected to the housing 2 via a screw connection (not shown). For the rest, the base plate support 46 is not bearing-connected to the housing 2. In other words, the base plate support 46 bears on the housing 2 via the screw connection on the left and right front sides of the housing 2, as well as via the support 54.

The rear support strip 52 is provided with support lugs 56 which are arranged and positioned to receive the weight of the base plate 34. The base plate support 46 is gas-tightly connected to a sealing strip 58. In the cross-section of Fig. 2, the sealing strip 58 becomes relaxed state. When the base plate support is mounted, as shown in Fig. 2, the sealing strip 58 will of course lie against an inside of the housing 2. In this exemplary embodiment, the sealing strip 58 is formed from a plastic polymer, in particular an elastomer, in this exemplary embodiment, Ethylene-Propylene-diene monomer (EPDM).

The base plate support 46 is further provided with a rubber sealing profile 60, in this case a sealing profile with an O-shaped cross-section. The rubber sealing profile 60 extends at the top of the base plate support 46 near an inner edge thereof. Rubber retains its resilience and sealing effect with repeated pressing. In the position of use of figs. 1-3 rests the base plate 34 with its weight and that of the components mounted thereon, including the heat block 20 and the condensate collector 22, on the housing 2 via on the one hand the cams 56 and the base plate support 46, and in particular the rear support strip 52 of this. On the other hand, the base plate 34 bearing the above-mentioned weight rests on the housing 2 via the hinges 36, 38. The base plate 34 is gas-tightly connected to the housing 2 via the rubber sealing strip 60, the base plate support 46, and the sealing strip 58.

The base plate 34 is provided with holes 61 through which pipes (not shown) extend for the supply and discharge of cold and hot water to and from the heat exchanger 18. The relevant pipes are flexible, so that the base plate 34 can pivot around the hinges 36, 38. The lead-through plate 50 includes lead-through holes 62 for a low-voltage cable harness, a high-voltage cable harness and the gas line 8 (not shown). Advantageous for the lead-through plate 50 and lead-through openings 62 are that they are fixed relative to housing 2 and do not move when the base plate 34 is moved outwards. Thus, the respective cable harnesses and gas line can be rigid and do not have to be provided with play.

- 10

In Fig. 12 it is clearly visible that hinge support 39 is provided with an elongated shaped hinge hole 64 with a length L that is greater than width B. The hinge hole 64 is moreover open to the outside via a lead-in opening, or recess 66 in the hinge support 39 The recess 66 thus makes it possible to suspend the base plate 34 with pre-assembled components such as the heat exchanger 18 from the housing 2 in one operation via the hinge pins 40 (Fig. 11). To that end, the recess 66 interrupts the hinge support 39 and 66 forms a continuous connection to the hinge hole 64. This continuous connection has a width equal to the width Bi of the recess 66 as seen in a plane perpendicular to the hinge pin 40. Bj and B are is slightly larger than the diameter D of the hinge pin 40, so that it can move through the recess 66 and hinge hole with some play. Slightly greater here is understood to mean that the clearance is more than 1% and less than 20%, in particular less than 10%, more in particular less than 5% of D.

Thanks to the elongated shape of the hinge hole 64, and the fact that the width B | 15 of recess 66 is smaller than the length L of the elongated hole 64, the base plate 34 hangs in the elongated hinge hole 64 without the risk that it falls out forwards. During the mounting, the hinge pin 40 moves in a direction perpendicular to its own longitudinal axis 41 through the recess 66 into the hinge hole 64. The hinge pin 40 then moves in the longitudinal direction of the hinge hole 64 until it is at the top of the hinge hole 64. In other words, the hinge support 39 now hangs on the hinge pin 40. Because the hinge pin 40 has moved away from the recess 66 in the hinge hole 64, it is now in a position of the hinge hole 64 where the hinge support 39 completely hides the hinge hole 64 in horizontal direction.

After hanging in, the base plate 34 is pivoted upward from the assembly position to the position of use of Figs. 1 - 3, or the maintenance position of figs. 4 - 8. As a result, the heat exchanger 2 moves through housing opening 3. During this upward tilting, the hinge pin 40 moves in the longitudinal direction of the hinge hole 64 through the hinge hole 64 from a first end 68 of the hinge hole 64 to the other end. 70 of these, where the hinge support 39 again completely limits the hinge hole 64 in the horizontal direction, so that also in this position the hinge support 39 cannot inadvertently become detached from the hinge pin 40. The heat exchanger 18 is then connected by means of a jib 72 the rear of the housing 2, so that in normal use it cannot pivot beyond the maintenance position of the housing 2. The jib 72 comprises two parts, which are connected to each other by hinges. One end of the jib 72 is hingedly connected to the housing 2 and another end of the jib 72 is hingedly connected to the heat exchanger 18. In the event of a failure of the jib 72, and during assembly work, the base plate 34 will cannot easily completely fall out of the housing, thanks to the aforementioned elongated shape of the hinge hole 64 and the positioning of recess 66 relative to this hole 64, as shown in FIG. 12. It is important here that the hinge support completely defines the hinge hole at the location of the hinge pin in the horizontal direction, both in the position of use, in the maintenance position, and in the assembly position.

With normal use, all parts are provided in the housing 2 as shown, for example, in FIG. 1. Of course, the aforementioned cables and cable trees (not shown) are also present, as well as a (not shown) door or cover on the front of the housing 2. In the case of maintenance, the front of the housing 2 (not shown) is removed. and the flue gas outlet 24 can also be removed. The condition of Fig. 3 is thus created. Subsequently, the base plate 34, with the heat block 20 present thereon, including burner 16 and fan 14, can be moved to a maintenance position, as shown in Fig. 4. In this maintenance position, the burner 16 can be moved. and the fan 14 are removed, thereby creating the state of FIG. In this state, the interior of the heat exchanger 18 can be inspected and cleaned, as can be seen in the plan view of Fig. 7. In the maintenance position, the base plate 34 securely hangs in the left and right hinge 36, 38 thanks to the elongated hinge opening 64 and the hinge pin 40, as shown in Fig. 8. Thereby, further tilting is limited by the jib 72.

Many variants are possible within the scope of the invention. Similarly, a heating device other than a central heating device can achieve the advantages of the invention, such as a hot water device. Although a gas-fired burner is currently common, other fuels, in particular fluid fuels, are also possible. Media other than water can also be heated in a heat exchanger.

In addition to hinged displacement means, other displacement means, including linear displacement means, for example telescopic extension means, or sliding means, are possible within the scope of the invention. Instead of a base plate, a bottom can also be formed in a different way and from other materials such as other plastics or metal. The bottom does not have to be plate-shaped and can form a larger or a smaller part of the gas-tight partition within the housing. In other words, the base plate support can form a larger part of the gas-tight partition within the housing. Instead of two hinges, one hinge can also be provided, for example with a shaft extending from one side of the housing to the other. More than two hinges are also possible.

The base plate support can also be formed from a different plastic than described above, or from a metal or other material. The metal housing may also be formed from a plastic. The base plate support can also be integrally formed with the housing within the scope of the invention, for example when it is formed as one injection molded part from plastic.

The hinge can also be designed differently. The hinge support with hinge hole and inlet opening can thus be fixedly connected to the housing, while the hinge pin is connected to the heat exchanger. In this case, the hinge hole and lead-in opening do not have to jointly define a T-shape, as in the exemplary embodiment shown, but can be one common through-opening, which extends at least partially vertically and with the lead-in opening to the top, or the front of the 10 heater has been used. The hinge pin will thus reach the underside of the hinge hole via the run-in opening, where it is bounded in horizontal direction by the hinge support, so that the hinge pin here cannot unintentionally get out of the hinge support. During tilting up of the heat exchanger in this variant of the invention the hinge pin will not move vertically through the hinge hole, but will remain at the bottom of this hinge hole.

Claims (11)

A heater, comprising a housing (2), a burner (16), a heat exchanger (18), a bottom (34) and displacement means, the burner (16) being operatively connected to the heat exchanger (18) for heating a medium flowing through the heat exchanger (18), the displacement means (36, 38) movably connect the heat exchanger (18) to the housing (2) to move between a position of use within the housing (2) and a maintenance position at least partially outside the housing (2), and the bottom (34) in the position of use connects gas-tightly to the housing (2) to define a gas-tight space (42) inside the housing (2), in which gas-tight space 10 (42) is located at least the burner (16) and the heat exchanger (18), characterized in that the heat exchanger (18) is fixedly provided on the bottom (34), and the bottom (34) such by means of the displacement means (36, 38) is connected to the housing (2) that the heat erase the operator (18) and the bottom (34) are jointly movable between the position of use and the maintenance position. 2. Heating device as claimed in claim 1, further comprising a feed-through element (50) which is gas-tight and fixedly connected to an inner side of the housing (2) and comprises at least one feed-through hole (62) for feeding a pipe to the gas-tight space 20 ( 42), wherein the bottom (34) comprises a recess corresponding to the lead-through element (50), and the bottom (34) connects in the position of use to the lead-through element (50) for jointly delimiting the gas-tight space within the housing (2) . 3. Heating appliance as claimed in any of the foregoing claims, further comprising a support (48, 52), which support (48, 52) is provided on an inner side of the housing (2) and is adapted to receive the bottom (34) ) in the position of use. A heater according to claims 2 and 3, wherein the lead-through element (50) and the support (48, 52) are formed as one component (46). 30 The heater of any one of claims 3-4, wherein the heat exchanger (18) is provided on the bottom (34) and the bottom (34) supports the support (48, 52) in the position of use. - 14- The heater of any one of claims 3-5, wherein the support (48, 52) only has a power transmission connection to a front and / or rear of the housing (2). The heater of any one of claims 3-6, further comprising a gas-tight support seal (58) extending between the support (48, 52) and the housing (2). 8. Heating appliance as claimed in any of the claims 3-7, further comprising a gas-tight bottom seal (60) which, in the position of use, extends between the support (48, 52) and the bottom (34). 9. Heating device as claimed in any of the foregoing claims, wherein the displacing means comprise a hinge (36, 38) for tiltably connecting the bottom (34) to the housing (2). The heater of claim 9, wherein the hinge (36, 38) is provided at the front of the housing (2) and comprises a substantially horizontal hinge axis. A method for maintaining a heater according to any one of the preceding claims, comprising the steps of: moving the bottom (34) with the heat exchanger (18) to the maintenance position, cleaning an inside of the heat exchanger (18), and moving the bottom (34) back to the position of use with heat exchanger (18).