METHOD FOR COMMISSIONING A HEATING APPLIANCE, COMPUTER PROGRAM, AND HEATING APPLIANCE

Description

[0001] The invention relates to methods for commissioning a heating device, a computer program product, a control and regulating device and a heating device.

[0002] To start up heaters, a mixture of fuel gas and combustion air is often injected into a burner and ignited by an ignition. It has been shown that, particularly in heaters with a pneumatic gas-air system, the composition of the gas mixture used for ignition can fluctuate due to system-related factors. These fluctuations are due, among other things, to tolerances and the dynamic characteristics of the gas valve, fluctuations in the calorific value of the gas being burned, and / or the characteristics, particularly the flow resistance, of the heater's exhaust system.

[0003] As a result, if the proportion of fuel gas is too high, ignition may be accompanied by loud noises. If the proportion of fuel gas is too low, the gas mixture may not be ignitable and / or several ignition processes may be necessary for commissioning. Both consequences are unpleasant for the user and also place increased strain on the heater. Furthermore, these consequences may require a service technician to perform maintenance, which incurs corresponding costs.

[0004] To reduce pollutant emissions during the start-up process of a heater, DE 41 42 841 A1 proposes promoting the ignition process with the full combustion air flow provided at operating temperature and, if flame formation fails, performing a new ignition process with a reduced combustion air flow. However, the proposed method increases the risk of a hard ignition with the associated risk of damage to the heater.

[0005] EP 3 054 216 A1 describes a control method for a switch-on function sequence in a fuel-operated heater. It is proposed that, during switch-on, the same amount of fuel but a smaller air mass be supplied during a transition phase, thus reducing the air / fuel ratio lambda for a defined period, which can last up to 20 seconds, compared to the ratio in the steady state. This allows for faster warm-up of the components involved in mixture formation, combustion, and heat transfer, and thus reduces the emissions of certain exhaust gas components during the transition phase. However, this method is not applicable to the commissioning of a heater with a pneumatic gas-air system, since in this case the supplied gas quantity is coupled to the incoming air quantity.In addition, lowering the fuel / air ratio during the start-up phase could lead to an unsafe operating condition, such as hard ignition, if the tolerances are unfavorable and the dynamic characteristics of the gas valve are unfavorable.

[0006] DE 15 01 894 A1 describes a method for regulating the air flow of automatically operating gas burners, by which the air flow is adapted to the purging and ignition process as well as to the normal operation of the burner. It is proposed that, upon starting the gas burner, it should initially operate at maximum power and then reduce its power to an ignition power level in order to increase the fan power back to nominal power after ignition. This method also fails to avoid the aforementioned problems, namely the effects of tolerances and dynamic characteristics of the gas valve on the combustion air ratio.

[0007] EP 3 301 365 A1 also describes a method for controlling the ignition operation of a heating system, in which at least one operating parameter detected before the ignition operation is taken into account. This parameter is suitable for determining the quality of the fuel used and / or a power requirement. It is further proposed that a starting power of the heating system be selected close to a power requirement. However, the method is not suitable for incorporating or mitigating the effects of a dynamic characteristic of the gas valve on the set combustion air ratio.

[0008] Influencing or regulating the composition of the combustion mixture is particularly difficult in a pneumatic (combustion) gas-air system because it is created by the interaction of mechanical components. While there are known ways to influence this, such as a device for limiting the gas flow and / or a buffer storage tank, it has been shown that, under certain conditions, their use can exacerbate the aforementioned problems in certain situations during the start-up process. Furthermore, these options are associated with costs. Another disadvantage is that the complexity of a heater equipped with them increases.

[0009] Based on this, the object of the invention is to propose a method for starting up a gas heater with a pneumatic gas-air system that at least partially overcomes the problems described in the prior art. In particular, a safe and reliable start-up process should be ensured in virtually all scenarios and operating situations.

[0010] In addition, the proposed method should be easy to implement and at least not significantly increase the complexity of a heating device.

[0011] These objects are achieved by the features of the independent patent claims. Further advantageous embodiments of the solution proposed here are specified in the independent patent claims. It is pointed out that the features listed in the dependent patent claims can be combined with one another in any technologically expedient manner and define further embodiments of the invention. Furthermore, the features specified in the patent claims are further specified and explained in the description, with further preferred embodiments of the invention being presented.

[0012] The method proposed here is particularly suitable for gas heaters with a pneumatic gas-air combination. In such heaters, the combination of combustion air and combustion gas is essentially based on mechanical principles. Combustion gas is often added to an air stream conveyed by a conveying device using a Venturi nozzle. The supplied gas stream is thus a delayed reflection of the air stream generated by the conveying device. This purely mechanical combination of combustion gas and combustion air has the disadvantage of being very limited in its adaptability and controllability.

[0013] The composition of the combustion mixture has a reference composition suitable for the starting process. A composition with a lower proportion of fuel gas than the reference value is referred to as lean. Ignition of a lean combustion mixture is difficult, although high ignition performance can be advantageous. A composition with a higher proportion of fuel gas than the reference value is referred to as rich.

[0014] The composition of the combustion mixture has a reference composition suitable for the ignition process. A composition with a lower proportion of combustion gas than the reference value is referred to as lean. Ignition of a lean combustion mixture is difficult, although high ignition performance can be advantageous. A composition with a higher proportion of combustion gas than the reference value is referred to as rich.

[0015] The composition of the combustion mixture can also be specified by a combustion air ratio λ, which represents the ratio of the air mass actually available for combustion to the air mass required for complete combustion. A combustion air ratio of (significantly) above 1 thus indicates a lean mixture, in which more combustion air is available than is necessary for the combustion of the existing combustion gas. Accordingly, a combustion air ratio of less than 1 indicates a rich combustion mixture, in which insufficient combustion air is available for complete combustion.

[0016] The invention is based on the idea that the mixture composition can be influenced by controlling the conveying device. When a heater is put into operation, the output of a conveying device is generally increased largely linearly with the greatest possible gradient up to a reference output, whereby the flow rate of the combustion air reaches a reference flow rate at the reference output. Shortly before or in the area of ​​reaching the reference flow rate, the gas valve opens and adds combustion gas to the conveyed fluid flow of the combustion air, for example through the Venturi effect. Due to its characteristics, a gas peak often occurs when the gas valve opens, i.e. a region of the fluid flow of the combustion mixture which contains a significantly higher proportion of combustion gas than in the resulting operating state.According to the invention, this gas peak can be used to advantage for an ignition process, for example, when the combustion mixture composition is lean. In other situations, such as when the combustion mixture composition is rich, the gas peak can have a detrimental effect on an ignition process and should be reduced or dampened.

[0017] By specifically influencing the fluid flow conveyed by the conveying device, a rich mixture composition (i.e. a mixture composition with a high proportion of combustion gas) can be leaned out for the ignition point, and a leaner mixture composition (i.e. a mixture composition with a low proportion of combustion gas) can be enriched.

[0018] It has been shown that the severity of a gas peak when a gas valve is opened can be influenced, among other things, by the combustion air flow rate. For example, opening the gas valve at a flow rate significantly below the reference flow rate can lead to a reduction in the gas peak and thus be suitable for igniting rich combustion mixtures. In contrast, with a lean combustion mixture, the gas peak can be a welcome increase in the proportion of combustion gas in the combustion mixture for an ignition process.

[0019] The method for commissioning a gas heater with a pneumatic gas-air connection comprises operating the heater with a start-up profile during commissioning, and the start-up profile is adapted to the dynamic behavior of the mixture composition and to the formation of a gas peak during an ignition process, wherein the start-up profile comprises a power curve of a conveyor device of the heater and an opening time of a gas valve, wherein the power curve of a start-up profile comprises the following processes: a) Increasing the output of the conveying device up to a (specifiable first) output with a (defined, in particular constant, first) increase, b) Opening the gas valve after reaching the (specifiable first) output and initiating an ignition process in the burner, c) Keeping the (specifiable first) output (as far as possible) constant for a (specifiable first) period of time, d) Controlling a (specifiable second) output of the conveying device (which differs from the specifiable first output) with a (defined, in particular constant, second) increase.

[0020] A start profile within the meaning of this document can be a defined procedure or a specification of several different variable start parameters for commissioning components of the heater, with the aim of enabling a problem-free start-up of the heater. The parameters coordinated within the framework of the start profile can include, for example, a power curve of a conveyor device for the combustion gas mixture or the combustion air, an ignition time of the burner, an ignition intensity and / or an instruction for operating a pneumatic restriction. The start profile determines in particular a temporal progression of a (possibly variable) setting of a parameter as well as an action and / or a temporal progression of a (possibly variable) setting of at least one further parameter. The start profile can have a (pre-selected) rigid, if necessary.a time-fixed sequence of the two variable start parameters for commissioning the heater, for example for a specifically determined situation (fuel, fault messages, initial / recommissioning, etc.). Alternatively or cumulatively, it is also possible for the setting of the two variable start parameters to be regulated during commissioning within the framework of the start profile using current parameters (particularly those determined during operation). It goes without saying that a start profile should also be tailored to the specific properties of the heater or heating system. In this context, particular mention should be made of the heater's output, properties of the combustion chamber, properties of the exhaust system, particularly its length, and / or the specific fuel gas.

[0021] A performance curve of the conveying device can specify a curve of a performance parameter of the conveying device as a function of the time the conveying device of the heating system is operated during commissioning. The performance parameter can be any parameter that characterizes the performance of the conveying device, for example, the speed of a fan as a conveying device, a flow rate, and / or the power consumption of the conveying device.

[0022] According to a preferred embodiment of the method, one start profile can be selected from at least two start profiles and the method can be executed. If this execution of the method does not lead to a successful start, the method can subsequently be executed with a different start profile, and so on. For this purpose, the start profiles can be stored with a prioritization, i.e., an indication of the order in which a process execution is attempted with these start profiles.

[0023] According to a preferred embodiment, the method may additionally or subsequently comprise the following processes: e) keeping the (specifiable second) power of the conveyor (as far as possible) constant for a (specified, second) period of time, f) controlling a (specifiable third) power which differs from the specifiable second power with a (defined, in particular constant, third) increase.

[0024] For clarification, it should be noted that the increases can take both negative and positive values. "Increase" here refers specifically to a linear increase; the resulting change in performance can also be caused by any other function, such as an exponential function or a logarithmic function.

[0025] According to a preferred embodiment of the method, specific start profiles can be defined, for example, for lean and / or rich mixture compositions and / or for long exhaust systems. The start profiles do not have to be assigned a specific purpose; a multitude of different start profiles can also be stored, and the most suitable one can be determined by processing the various start profiles.

[0026] For example, a starting profile for a normal start or also for a rich mixture composition (it has been shown that a suitable starting profile for a normal start is also suitable for a rich mixture composition in many heaters) can include a performance curve with at least the following features: Starting up a conveyor of the heater with a high (first) rise, i.e. high acceleration (a high or large acceleration should nevertheless enable the most precise control of the intended (first or second) power) up to a (first) power between 20% and 40% of the conveyor power, which corresponds to the maximum power of the heater (in other words, the power at which the conveyor is operated at maximum power of the heater); often, a conveyor power corresponding to a maximum power of a heater can be in the range of 10,000 rpm [revolutions per minute]. Opening the gas valve, starting an ignition process with normal settings (characterised, for example, by an average ignition energy and / or ignition frequency). Waiting for a (first) period of approx.0.1s to 0.3s [seconds], to stabilize the flame, whereby the power of the conveyor remains as constant as possible, increase the power of the conveyor up to a (second) power in the range between 60% and 70% of the power of the conveyor, which corresponds to the maximum power of the heater with a high (second) increase, which can correspond approximately or exactly to the previous (first) increase, reduce the power of the conveyor to a (third) power in the range of between 20% and 40% of the power of the conveyor, which corresponds to the maximum power of the heater with a (third) increase, the amount of which corresponds largely to two thirds of the first selected (first) increase.

[0027] For example, a starting profile for a lean mixture composition may include a power curve with at least the following features: Starting up a heater's delivery system with a high (first) increase, i.e. high acceleration up to a (first) output in the range between 30% and 60% of the delivery system's output, which corresponds to the heater's maximum output, opening the gas valve, starting an ignition process with settings for a lean mixture composition (this can have a higher ignition energy and lower ignition frequency than a normal ignition process). No waiting, or only a very short (first) period of a maximum of 0.1 seconds with the delivery system's output remaining largely constant, increasing the delivery system's output up to a (second) output in the range between 75% and 95% of the delivery system's output, which corresponds to the heater's maximum output, with a (second) increase that largely corresponds to two-thirds of the previous (first) increase.

[0028] For example, a starting profile for a long exhaust system (for example, from a length of approximately 8 meters, where the properties of the exhaust system, such as its volume, as well as the specific properties of the heater, for example the volume of the combustion chamber, can be taken into account) can include a performance curve with at least the following features: Starting up a feed device of the heater with a high (first) increase, i.e. high acceleration up to a (first) output in the range between 62% and 82% of the feed device output, which corresponds to the maximum output of the heater, opening the gas valve, starting an ignition process with settings that correspond to those for a lean mixture composition, waiting for a (first) period of approx. 0.2s to 0.4s [seconds] to stabilize the flame, whereby the feed device output remains largely constant, reducing the feed device output down to a (second) output in the range between 54% and 74% of the feed device output, which corresponds to the maximum output of the heater with a very high amount of negative (second) increase, for example achieved by switching off the feed device, waiting for a (second) period of approx.2s to 4s [seconds], with the power of the conveyor remaining as constant as possible, increasing the power of the conveyor to a (third) power in the range between 62% and 82% of the power of the conveyor corresponding to the maximum power of the heater, with a (third) increase that approximately corresponds to the first selected (first) increase.

[0029] After a successful ignition process, the heater can enter normal operating mode after the completion of the start profile. Each of the above-mentioned start profiles is tailored to the dynamic behavior of the mixture composition, particularly the formation of a gas peak, during an ignition process and can enhance or counteract the natural behavior of the mixture composition.

[0030] As a precaution, please note that the start profiles described above are only examples. The design of the start profiles depends, among other things, on the specific heater, its performance data and exhaust system, and the properties of the fuel used. Therefore, when implementing the start profiles, steps may be omitted or added to meet the specific requirements of the heater being operated.

[0031] In a preferred embodiment of the method, the conveying device can be a fan. The performance curve of the conveying device can relate, among other things, to a speed of the fan.

[0032] According to a preferred embodiment of the method, after an unsuccessful start-up process, in particular after an unsuccessful ignition process, a new start-up process can be initiated with a different start-up profile. For example, different start-up profiles can be tried for different possible situations until a start-up profile is found that enables a successful start-up process.

[0033] According to a preferred method, an ignition control procedure can be carried out during a process run, which includes the evaluation of an ionization signal. An ionization signal from a flame allows for a quick and direct conclusion as to whether a flame is present, as well as the quality and stability of the flame.

[0034] According to a preferred embodiment of the method, at least one of the following features of the ionization signal is included: a period of time between opening the gas valve and the first occurrence of the ionization signal, a number of occurrences of the ionization signal during an ignition process, a strength of the ionization signal, and an intensity of noise of the ionization signal.

[0035] Within the scope of the ignition control procedure, a (current) performance of the conveying device, in particular a speed of a fan as a conveying device, can be included at the time of the ionization signal.

[0036] According to a preferred embodiment, an evaluation of the executed start profiles can be performed within the framework of the ignition control method. This evaluation is preferably stored. The evaluation can relate in particular to various aspects that characterize the success of the ignition process for the respective start profile.

[0037] According to a further preferred embodiment, the stored evaluation can be used to select a start profile during subsequent startup of the heater. Thus, if the mixture composition shifts due to design features of the gas valve, it can be assumed that these will not change during each startup. This advantageously ensures that, at least frequently, the heater is started with a start profile that enables problem-free startup. This advantageously shortens the duration of a startup process by selecting a successful start profile right from the start.

[0038] According to a preferred embodiment, the at least one evaluation of a start profile can be deleted after a certain number of unsuccessful attempts. Preferably, the method can commission the heater using a standardized sequence of start profiles and then re-evaluate the start profiles. For example, due to wear on the gas valve or a change in the composition and / or calorific value of the fuel, it may become apparent over time that the highest-rated start profile no longer guarantees a successful ignition process. A re-evaluation process can then find the most suitable start profile at that time.

[0039] According to a preferred embodiment, after a defined number of unsuccessful attempts to start the heater with different start profiles, the heater can switch to a fault mode. For example, the defined number of attempts can include attempting each stored start profile twice.

[0040] According to a further aspect, a heating device with a pneumatic gas-air connection, at least one conveying device, a gas valve, and a regulating and control device is proposed, wherein the regulating and control device is configured to cause the heating device to carry out the steps of the method described here.

[0041] It is possible to carry out the method as a computer-implemented method, comprising steps a) to d). It is possible to provide a device or a data processing system comprising means for carrying out these steps of the method specified here.

[0042] According to another aspect, a computer program is also proposed which is configured to carry out a method presented here. In other words, this relates in particular to a computer program (product) comprising instructions which, when executed by a computer, cause the computer to carry out a method described here. According to a further aspect, a machine-readable storage medium is also proposed on which the computer program is stored. According to a preferred embodiment, at least one start profile defined according to the invention is stored on the memory. The machine-readable storage medium is usually a computer-readable data carrier.

[0043] According to a further aspect, a control and regulating device for a heater is also proposed, configured to carry out a method presented here. For this purpose, the control and regulating device can, for example, have or be equipped with a processor. In this context, the processor can, for example, execute the method stored in a memory (of the control and regulating device). Preferably, at least one start profile defined using a method proposed here is stored in the memory. Particularly preferably, several start profiles are stored, along with a sequence of the stored start profiles.

[0044] According to a further aspect, a heater with a control and regulation device as presented here is also proposed. The heater is a gas heater with a gas burner and a conveying device that can convey a pneumatic gas-air mixture to the gas burner.

[0045] In particular, the use of a flame ionization signal to control the ignition process of a heater with a pneumatic gas-air connection is proposed. Furthermore, the use of a flame ionization signal of a heater with a pneumatic gas-air connection to select a suitable start profile is also proposed.

[0046] Thus, a method for commissioning a heater, a computer program product, a control device, a heater, and uses are specified here, which at least partially solve the problems described with reference to the prior art. In particular, the method, the computer program, the control device, and the heater each contribute at least to shortening the starting behavior of a heater and preventing the occurrence of ignition attempts in borderline areas, thus significantly increasing operational reliability. Furthermore, implementing the method does not require any structural changes to a heater, which advantageously allows the invention to be implemented cost-effectively and, moreover, does not increase the complexity of a heating system.

[0047] The invention and the technical environment are explained in more detail below with reference to the accompanying figures. It should be noted that the invention is not intended to be limited by the exemplary embodiments cited. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in the figures and combine them with other components and findings from the present description. In particular, it should be noted that the figures, and in particular the proportions shown, are only schematic. They show: Fig. 1 : a sequence of a procedure proposed here, Fig. 2 : a course of an ionization signal during commissioning of a heater, Fig. 3 : a performance curve of a conveyor of a starting profile for a rich mixture composition, Fig. 4 : a performance curve of a conveyor of a starting profile for a lean mixture composition, and Fig. 5 : a performance curve of a conveyor of a starting profile for a long exhaust system.

[0048] Fig. 1 shows, by way of example and schematically, the sequence of a method proposed here for commissioning a heater. When the method is started 0, a start profile 1 can be selected from a prioritization list. As a rule, a start profile 1 can be started with a first start profile in the order of the prioritization list and a start-up process 2 can be carried out with this start profile. The prioritization list can specify various start profiles, preferably stored in a memory of the heater, in particular on a control and regulation unit of the heater. The prioritization list can specify an order of the start profiles, whereby the order can be designed such that the start profile with the highest chance of success is at the first position, and the other stored start profiles follow according to their chance of success.When starting the procedure for the first time, for example after a new installation of a heating device, a standard prioritization list can be used, which may be pre-installed by the manufacturer with a sequence of start profiles.

[0049] During the start-up process 2, the heater can be operated with the selected start profile, wherein the start profile includes a power curve for operating a conveyor device 3 and parameters for operating an ignition device 4. The conveyor device 3 can be a fan, and the power curve can specify a fan speed as the power of the conveyor device 3 as a function of time. The parameters for operating the ignition device 4 can be, for example, an intensity of the ignition spark and / or a frequency of the ignition spark.

[0050] During the start-up process 2, an ionization signal 5 of the flame can be detected. Parallel to the start-up process 2, an ignition control process 6 can be performed, which can include various operating parameters, such as the ionization signal 5, the opening time of a gas valve, and the performance of the conveyor device 3. Within the scope of the ignition control process 6, it can be determined whether the start-up process 2 was successful. If the start-up process 2 is successful, the heater can transition to a normal operating mode 7.

[0051] If the ignition control procedure 6 determines that the start-up process was unsuccessful, a start-up counter 8 can be incremented. If the start-up counter 8 now indicates a maximum number of start-ups 2, the heater can enter a fault mode 9 and block further start-ups for safety reasons. In addition, the heater could indicate in fault mode that maintenance by a service technician is required.

[0052] If the boot process counter 8 has not yet reached the maximum number of boot processes 2, another boot process 2 can now be initiated. The next boot process 2 can be initiated with the boot profile following in the order of the prioritization list.

[0053] Following or at least partially parallel to the ignition control process 6, an evaluation 10 of the executed start profile can be performed. The evaluation particularly includes the ionization signal 5 and evaluates the quality of the start process 2 and the start profile used.

[0054] Following evaluation 10, prioritization list 11 can be determined. During the determination of prioritization list 11, it can be checked whether the order of the prioritization list has changed due to evaluation 10 of the last launch process 2 and the launch profile used. The determination of prioritization list 11 can then be made available for a future selection of a launch profile 1.

[0055] If, for example, it is determined during several start-up processes 2 that the third start profile in the sequence of the prioritization list has led to a successful start-up process 2, the third start profile in the prioritization list can be moved to the first position in the sequence as part of the determination of the prioritization list 11. As a result, the heater can initiate a first start-up process 2 with this start profile during future start-up processes 2, thus shortening the overall duration of the start-up process.

[0056] According to an advantageous embodiment, a "successful" start profile, for example, one that has enabled a successful start in a large number of consecutive cases, can be further adjusted by adjusting one or more parameters. An advantageous adjustment could, for example, be a shortening of the ignition time to enable an even faster start-up process. Should a problem occur during a start-up process after adjusting a parameter, the adjustment can subsequently be reversed.

[0057] If it is determined that a first start profile (the most successful start profile with the best rating so far) determined in the course of multiple evaluations 10 and determinations of the prioritization list 11 no longer guarantees a successful start process 2, the (defined prioritization list) can be deleted and the standard prioritization list can be started again.

[0058] Fig. 2 shows an ionization signal 5 during a starting process 2. The diagram shows the strength of the ionization signal 5 over a time t. Ignition sparks 12 are emitted by an ignition device 4. The diagram shows an ionization signal 5 that, due to the technical equipment used, is lower the higher the quality of the measured flame.

[0059] At the start of an ignition process, the ionization signal 5 can assume a high value because no flame is present. Essentially at the same time as the gas valve 13 opens, the ignition device 4 begins to generate ignition sparks 12. At a time 14, a first flame can be detected based on a significantly lower ionization signal 5. At a time 15, a loss of flame occurs. At a time 16, a stable flame forms.

[0060] Various indicators for an evaluation 10 of a start profile can be derived from an ionization signal 5. These can include, in particular, an ignition period 17 (the period between the opening time 13 of the gas valve and the time 16 of the stable flame), a number of times 15 at which a loss of flame occurred, a signal strength 18 of the stabilized flame, and an intensity of signal noise 17 of the stabilized flame.

[0061] Fig. 3 showed a performance curve 23 of a conveyor 3 for a (exemplarily selected) starting profile for a rich mixture composition. This performance curve 23 can also be applied to a general starting profile. The diagram shows a fan speed n, which is given as a percentage of a conveyor power corresponding to the maximum power of the heater, as a function of time t. The representation in the Fig. 3 bis 5 is for illustrative purposes only and is not to scale.

[0062] The performance curve 23 of the conveyor device 3 for a starting profile for a rich mixture composition can, for example, have the following features: Starting up a conveyor 3 of the heater with a (first) increase A1 18 of 150 rpm / 0.1s [(revolutions per minute) per 100 milliseconds] up to a (first) power L1 of 30%, opening the gas valve at an opening time 20, starting an ignition process at an ignition time 28 with normal settings, waiting for a (first) period D1 19 of 0.2s [seconds] to stabilize the flame, whereby the power of the conveyor 3 remains largely constant, increasing the power of the conveyor 3 up to a (second) power L2 of the power of the conveyor, which corresponds to the maximum power of the heater with a high (second) increase A2 21 of 150 rpm / 0.1s [(revolutions per minute) per 100 milliseconds], reducing the power of the conveyor to a (third) power L3 of 30% with a (third) increase A3 23 of - 100 rpm / 0.1s [(revolutions per minute) per 100 milliseconds],End of the power curve 22 and control of the flame via the ionization signal 5. ,

[0063] Fig. 4 showed a power curve 24 of a conveyor 3 for a starting profile for a lean mixture composition. The representation is analogous to Fig. 3 .

[0064] The power curve 24 of the conveyor device 3 for a starting profile for a lean mixture composition can, for example, have the following features: Starting a feeder 3 of the heater with a (first) increase A1 18 of 150 rpm / 0.1s [(revolutions per minute) per 100 milliseconds], up to a (first) power L1 of 45% of the power of feeder 3, which corresponds to the maximum power of the heater; opening the gas valve at an opening time 20; starting an ignition process at an ignition time 28 with settings for a lean mixture composition; no waiting (the (first) period D1 is 0s [seconds]); increasing the power of feeder 3 up to a (second) power L2 of 85% with a (second) increase A2 21 of 100 rpm / 0.1s [(revolutions per minute) per 100 milliseconds]; end of the power curve 22; and flame control via the ionization signal 5. A lower increase A2 can make it easier for a control unit of the heater to regulate to a suitable power and to stabilize a flame. This starting profile is particularly suitable for lean mixture compositions, especially in conjunction with short exhaust systems.

[0065] Fig. 5 showed a performance curve 25 of a conveyor 3 for a starting profile for a long exhaust system. The representation is analogous to the Fig. 3 or 4.

[0066] The performance curve 24 of the conveyor device 3 for a starting profile for a long exhaust system can, for example, have the following features: Starting up a feed device 3 of the heater with a (first) increase A1 18 of 150 rpm / 0.1s [(revolutions per minute) per 100 milliseconds] up to a (first) power L1 of 72% of the power of the feed device 3, which corresponds to the maximum power of the heater, opening the gas valve at an opening time 20, starting an ignition process at an ignition time 28 with settings corresponding to those for a lean mixture composition, waiting for a (first) period D1 19 of 0.3s [seconds] to stabilize the flame, whereby the power of the feed device 3 remains largely constant, reducing the power of the feed device 3 up to a (second) power L2 of 64% of the power of the feed device 3, which corresponds to the maximum power of the heater, a (second) increase A2 21 of -600 rpm / 0.1s [(revolutions per minute) per 100 milliseconds], waiting for a (second) period D2 26 of approx.3s [seconds], whereby the power of the conveyor 3 remains largely constant, increase the power of the conveyor 3 to a (third) power L3 between 62% and 82% of the power of the conveyor, which corresponds to the maximum power of the heater, with a (third) increase A3 which approximately corresponds to the (first) increase A1 18, end of the power curve 22 and control of the flame via the ionization signal 5. . List of reference symbols

[0067] 0Procedure start 1Start profile selection 2Start-up process 3Feeding device 4Ignition device 5Ionization signal 6Ignition control process 7Normal operating mode 8Start-up process counter 9Fault mode 10Evaluation 11Determination of prioritization list 12Ignition spark 13Gas valve opening time 14First flame time 15Flame loss time 16Stable flame time 17Signal noise 18(First) rise A1 19(First) period D1 20Gas valve opening time 21(Second) rise A2 22End of power curve 23Power curve for rich mixture composition 24Power curve for lean mixture composition 25Power curve for long exhaust system 26(Second) period D2 27(Third) rise A3 28Ignition time

Claims

1. Method for starting up a gas heater with a pneumatic gas / air assembly, wherein the heater is operated with a start profile during start-up and the start profile is adapted to the dynamic behaviour of the mixture composition and to the formation of a gas peak during an ignition procedure, and comprises at least one output curve (23, 24, 25) of a conveying apparatus (3) of the heater and an opening time (13, 20) of a gas valve, wherein the output curve (23, 24, 25) of a conveying device (3) of a start profile comprises at least the following processes: a) increasing the output of the conveying apparatus (3) up to an output L1 with an increase A1 (18) b) opening the gas valve after reaching the output L1 and initiating an ignition procedure, c) keeping the output L1 constant for a period D1 (19), d) controlling an output L2 of the conveying apparatus (3) with an increase A2 (21).

2. Method according to claim 1, wherein the following processes are additionally carried out: e) the power is kept largely constant for a period D2 (26), f) controlling an output L3 with an increase A3 (27).

3. Method according to any one of the preceding claims, wherein, after an unsuccessful starting procedure (1), a new starting procedure (1) is initiated with a different starting profile.

4. Method according to any one of the preceding claims, wherein after the method has been executed, an ignition control method (6) which comprises an evaluation of an ionisation signal (5) is initiated.

5. Method according to claim 3, wherein at least one of the following features of the ionisation signal (5) is included: period of time between an opening time (13, 30) of the gas valve and the first occurrence of the ionisation signal (5), number of occurrences of the ionisation signal (5) during an ignition procedure, strength of the ionisation signal (5), noise of the ionisation signal (5).

6. Method according to any one of claims 3 or 4, wherein the output of the conveying apparatus (3) when the ionisation signal (5) occurs is included in the evaluation of the ionisation signal (5).

7. Method according to any one of claims 4 to 6, wherein in the ignition control method (6) at least one evaluation (10) of the start profile carried out is performed and stored.

8. Method according to claim 7, wherein the order of the start profiles is selected on the basis of the at least one evaluation (10).

9. Method according to any one of claims 7 or 8, wherein the at least one evaluation (10) is deleted after a defined number of unsuccessful start procedures (1).

10. Heater having a pneumatic gas / air assembly and at least one conveying apparatus (3), a gas valve and a regulating and control appliance, wherein the regulating and control appliance is arranged to cause the heater to carry out the steps of the method according to any one of the preceding claims.

11. Computer program comprising commands that cause the heater of claim 10 to carry out the steps of the method according to any one of claims 1 to 9.

12. Machine-readable storage medium on which the computer program according to claim 11 is stored.