Combustion unit and conversion system of a gas-fired heating appliance

Abstract

The object of the present invention is a retrofit kit (R) comprising a monoblock combustion unit, to be installed in a standard gas combustion heating equipment to convert it into a hydrogen-fuelled combustion heating equipment (C). Such retrofit kit (R) comprises at least: - a closing door (1), adapted to couple to the combustion chamber (22) of said equipment (C), said closing door (1) acting as a load-bearing structure for the remaining components of said retrofit kit (R); - a complete-premixing and modulable-power burner (2), protruding from the inner face of said closing door (1); at least an ignition electrode (3); a mixing unit (7) for mixing combustion air and fuel gas, to form an air-gas mixture; a first feeding conduit (4) to said burner (2) of the air-gas mixture obtained in said mixing unit (7); a fan (6) configured to provide a combustion air flow to said mixing unit (7); a gas valve (9) configured to deliver fuel gas to said mixing unit (7) via a second feeding conduit (8); - an electronic card (SR) for managing and regulating the combustion, control and safety parameters of said retrofit kit (R) and said equipment (C); - a communication cable (11) exiting such electronic card (SR), adapted to be connected to the main electronic card (SC) present on said equipment (C).

Description

[0001] COMBUSTION UNIT AND CONVERSION SYSTEM OF A GAS-FIRED HEATING APPLIANCE DESCRIPTION

[0002] The object of the present invention is a monoblock combustion unit for retrofit installation into a standard gas combustion heating equipment, in particular a gas boiler originally fuelled by fossil fuels (particularly light hydrocarbons such as methane, butane, ethane, and propane), for converting it into a gas boiler fuelled by pure hydrogen or high hydrogen content fuel gas.

[0003] The object of the present invention is also a method for converting a standard gas combustion heating equipment, particularly a gas boiler, natively fuelled by fossil fuels (particularly light hydrocarbons such as methane, butane, ethane, and propane), into a boiler fuelled by pure hydrogen or high hydrogen content fuel gas.

[0004] In the present description and accompanying claims, “gas combustion heating equipment” or, briefly, “gas equipment” means any gas-fuelled combustion heating device for residential, commercial or industrial use, including at least a combustion chamber, a burner, a fuel gas and / or oxidant delivery system, and a combustion start system. The gas combustion heating equipment is for example a boiler, a water heater, a direct / reverse flow air heater, a power / jet burner, or any other gas-fuelled combustion heating equipment for residential, commercial, or industrial use. “Standard” specifically means a gas combustion heating equipment originally designed to be fuelled by fossil fuel gases.

[0005] By way of an example, the gas combustion heating equipment according to the invention is a boiler. In the present description and in the attached claims, “high hydrogen content” is intended to indicate a predominant hydrogen content by volume, for example a hydrogen content by volume equal to or greater than 90%, preferably equal to or greater than 95%, more preferably equal to or greater than 98%.

[0006] In the sector of gas combustion heating equipment, the need to facilitate the use of fuels from renewable sources rather than the traditional light hydrocarbons is increasingly felt, in order to reduce the polluting emissions into the atmosphere. In such sense, a solution is the use of hydrogen as a fuel gas, although it, due to the intrinsic combustion properties thereof, involves solving particularly challenging technical problems for minimising the risk of flashbacks or overheating of the surface of the burner and ensuring an adequate modulation range of the operating power of the burner.

[0007] For a more exhaustive description of the operation and peculiarities of an example of a gas boiler operating with a high hydrogen content fuel, please refer to the prior document EP4334643 owned by the same applicant for this patent.

[0008] Currently, almost all the gas boilers installed in buildings are designed to be fuelled by traditional fuels such as methane or propane, or possibly by mixtures of traditional fuels and hydrogen in which the latter, however, does not exceed the 20% by volume.

[0009] In other words, the stock of boilers currently installed is not capable of operating with pure or substantially pure hydrogen, and in such sense the conversion thereof needs significant modifications to the components, with important consequences in terms of costs and safety.

[0010] In particular, the use of hydrogen as a fuel gas in a boiler originally designed to operate with a completely different type of feeding results into significant safety risks for adapting the equipment, given the high flammability of hydrogen and the risk of detonation in case of nearby flames or sparks.

[0011] Such risks are amplified by the fact that the hydrogen is a colourless and odourless gas, making it difficult for the installer to notice any leaks during the modification step of the original boiler or, even worse, after the modification is completed and with the converted boiler already in operation.

[0012] Conversely, the modification of a boiler already installed with components that allow it to be fed with pure hydrogen or high hydrogen content fuel gas would certainly be a preferable operation for the user, rather than bearing the cost of a completely new boiler and the related installation works.

[0013] The object of the present invention is to obviate such types of drawbacks, by providing a monoblock combustion unit that may be retrofitted into a standard gas equipment originally designed to be fuelled by fossil fuels, so as to convert it into a gas equipment fuelled by pure hydrogen or by high hydrogen content fuel gas (i.e., having a hydrogen-volume content equal to or greater than 98%).

[0014] Another object of the present invention is to provide a reliable, quick, and safe procedure for retrofitting a monoblock combustion unit into a standard gas equipment, so as to convert it into a boiler fuelled by pure hydrogen or high hydrogen content fuel gas (i.e., having a hydrogen content by volume equal to or greater than 98%).

[0015] A further object of the invention is to allow a standard gas equipment, originally designed to be fuelled by fossil fuels, to be converted into a gas combustion heating equipment fuelled by pure hydrogen (or high hydrogen content fuel gas) through operations having a low risk of human error, ensuring the compliance with the necessary safety requirements during the installation and operation steps of a hydrogen equipment.

[0016] These and other objects, which shall become clear hereinafter, are achieved with a monoblock combustion unit that may be retrofitted on a standard gas combustion heating equipment and with the related retrofit conversion procedure, in accordance with the provisions of the independent claims 1 and 9, respectively. Other objects may also be achieved by means of the additional features of the dependent claims.

[0017] Further features of the present invention shall be better highlighted by the following description of a preferred embodiment, according to the patent claims and illustrated, purely by way of a non-limiting example, in the accompanying drawing tables, wherein:

[0018] - Figure 1 schematically shows the components of the monoblock combustion unit according to the invention;

[0019] - Figure 2 shows the monoblock combustion unit of figure 1, about to be retrofitted on a standard gas combustion heating equipment;

[0020] - Figure 3 is a flow diagram illustrating the main steps of the retrofit conversion method of the monoblock combustion unit according to the invention. The features of a preferred variant of the monoblock combustion unit according to the invention are now described, using the references contained in the figures. With reference to figure 1, R indicates, as a whole, the monoblock combustion unit according to the invention, adapted to be installed in a standard gas combustion heating equipment for converting it into a gas combustion heating equipment C operating with pure hydrogen or high hydrogen content fuel gas. Hereinafter in the description, reference shall be made, by way of an example, to the conversion of a standard gas boiler into a boiler fuelled by pure hydrogen or high hydrogen content fuel gas. The boiler already installed and intended to be subjected to the conversion with the monoblock combustion unit R according to the invention shall be hereinafter abbreviated to “standard boiler”; while the boiler resulting at the end of the conversion process shall be referred to as “hydrogen boiler C”

[0021] The monoblock combustion unit R according to the invention, hereinafter abbreviated as “retrofit kit R”, comprises at least the following components: - a closing door 1 of the combustion chamber 22, provided with a sealing gasket 1.1, adapted to couple and constrain to the combustion chamber 22 of the standard boiler;

[0022] - a burner 2, specifically a preferably complete-premixing and modulable-power cylindrical burner, suitable for the combustion of hydrogen, projecting from the inner face of the closing door 1 and adapted to extend into the combustion chamber 22 of the boiler, once the closing door 1 has been coupled to the perimeter flange 21 of such combustion chamber 22; - at least an ignition electrode 3, supported by said closing door 1 to extend inside the combustion chamber 22;

[0023] - a mixing unit 7 for mixing the combustion air and fuel gas, to form an air-gas mixture;

[0024] - a first feeding conduit 4 to the burner 2 for the air-gas mixture, obtained in the mixing unit 7, wherein the flows of combustion air (provided by a fan 6) and fuel gas (provided by a gas valve 9 via a second feeding conduit 8) flow into; - an electronic card SR for managing and regulating the combustion, control, and safety parameters of the retrofit kit R and hydrogen boiler C;

[0025] - a communication cable 11 exiting from such electronic card SR and intended to connect to the main electronic card SC already present in the standard boiler, in the manners and the purposes hereinafter described.

[0026] For the sake of graphical schematisation, the main electronic card SC of the boiler in the attached figures is shown in the proximity to the electronic card SR of the retrofit kit R, with which it communicates by means of the aforementioned communication cable 11 : however, it is clear that it is actually placed in the boiler, since the card is natively present in the standard boiler to be converted, originally dedicated to manage and control the comfort and safety parameters thereof. As shown in figure 1, the closing door 1 essentially serves as a load-bearing structure of the entire retrofit kit R, upon which all the other aforementioned components lean on a cascade, forming a monoblock combustion unit, structurally configured to be inserted and fixed in a standard boiler previously stripped from the components strictly dedicated to the combustion.

[0027] In the example of the attached figures, the air and fuel gas mixing unit 7 is positioned downstream of the fan 6; however, in an alternative embodiment (not shown), it may equally be positioned upstream of the fan 6.

[0028] Preferably, such mixing unit 7 comprises a Venturi tube, optionally provided with mass and / or volumetric sensors for monitoring the flow rates of the combustion air flows and fuel gas to be mixed.

[0029] The gas valve 9 may indifferently be either pneumatic, stepper, or electronic, depending on whether the combustion system provides for a pneumatic or electronic control.

[0030] According to a variant of the invention, the retrofit kit R may comprise additional components, such as:

[0031] - one or more sensor means 3.1 for detecting at least one combustion parameter, for example, flame detection sensors for the burner 2, such as UV or infrared optical sensors, or temperature sensors such as thermocouples or PCTs, supported by the closing door 1;

[0032] - a non-return valve 5 of the air-gas mixture (or safety devices with similar functions, adapted to prevent flashback, such as a flame arrester), located upstream of the first feeding conduit 4 of the mixture to the burner 2;

[0033] - an atmospheric sensor 10 for hydrogen leaks, for detecting any leaks of fuel gas composed of pure hydrogen or a high hydrogen content mixture.

[0034] Like the main components listed above, such optional components are also connected to the electronic card SR of the retrofit kit R via respective connection cables for the bidirectional exchange of the control and regulation signals between said electronic card SR and the specific component; therefore, the connection to the electronic card SR takes place through at least:

[0035] - a cable 3.S for the communication with the ignition electrode 3;

[0036] - at least a cable 3.1. S for the communication with one or more sensor means 3.1 to detect at least one parameter of the combustion, when present;

[0037] - a cable 6.S for the communication with the fan 6;

[0038] - a cable 7.S for the communication with the mixing unit 7;

[0039] - a cable 9.S for the communication with the gas valve 9;

[0040] - a cable 10.S for the communication with the atmospheric sensor 10 for hydrogen leaks, when present.

[0041] Figure 2 shows the retrofit kit R described above and a standard gas boiler, particularly a condensing gas boiler, intended to be converted into a hydrogen boiler C through the installation of the retrofit kit R.

[0042] For such boiler, not all the components necessary for the operation thereof are shown, as they are well known to the man skilled in the art, but only the casing 20, the combustion chamber 22 with the related perimeter flange 21 and the chimney 24 for the evacuation of the exhaust gases produced by the combustion. Reference 23 also shows the housing obtained inside the casing 20, below the combustion chamber 22, intended to spatially accommodate the components of the retrofit kit R that are supported by the outer face of the closing door 1, i.e., those components that, once the installation of the retrofit kit R has been completed, are not located inside the combustion chamber 22. Such housing 23 is positioned below and outside the combustion chamber 22.

[0043] In other words, the technician must first remove the components to be replaced from the standard boiler (step 101) and then proceed with the installation of the retrofit kit R in order to structurally convert a standard boiler into a hydrogen boiler C, through the following steps:

[0044] - step 102: inserting the burner 2 into the combustion chamber 22;

[0045] - step 103: fixing the closing door 1 to the perimeter flange 21 of the combustion chamber 22;

[0046] - step 104: placing the components of the retrofit kit R, supported by the outer face of the closing door 1, in the housing 23, spatially located below the combustion chamber 22;

[0047] - step 105: connecting the pre-existing connections for feeding fuel gas and combustion air to the respective components of the retrofit kit 3, namely the gas valve 9 and the fan 6, respectively;

[0048] The components to be replaced of the standard gas combustion heating equipment, particularly the standard boiler, are, for example, one or more elements selected among the closing door of the combustion chamber, the burner, the mixing unit, the ignition electrode, the fan, the gas valve adapted to deliver the fuel gas, and the fuel gas feeding conduit.

[0049] Figure 3 shows a block diagram that schematically summarises the steps just mentioned.

[0050] Such sequential operations prepare the hydrogen boiler C to be structurally suitable for the combustion of pure hydrogen or high hydrogen content fuel gas (i.e., having a hydrogen volume content equal to or greater than 98%).

[0051] In fact, as mentioned above, the burner 2 is of the type suitable for the combustion of hydrogen, thus capable of ensuring that the outlet speed of the air-gas mixture is always greater than the flame front speed, in order to avoid flashbacks, especially during the ignition step or at low powers.

[0052] Likewise, the other main components of the retrofit kit R are also selected and designed for the suitable hydrogen operation: the gas valve 9 features improved sealing characteristics compared to a conventional gas valve for fossil hydrocarbons, given the smaller size of the hydrogen molecules; while the fan 6 is of the type capable of preventing any production of electrostatic discharges, so as not to cause undesired ignitions of the air-gas mixture.

[0053] The procedure for converting a standard boiler into a hydrogen boiler C is completed by an updating step of the operating parameters thereof, necessary to allow the retrofit kit R to operate in accordance with the modes provided by a pure-hydrogen (or high hydrogen content) feeding rather than the previous fossil hydrocarbon feeding.

[0054] According to the prior art, the update of the operating parameters typically takes place either by replacing the electronic card of the standard boiler or by reprogramming the software of the existing electronic card: a specialist technician must therefore perform such additional operations, in addition to those already performed by the technician to structurally adapt the standard boiler through the installation of the retrofit kit R.

[0055] In accordance with the present invention, however, such modification step of the operating parameters takes places through a simple connection between the electronic card SR with which the retrofit kit R is equipped and the main electronic card SC (natively present in the standard boiler object of the conversion), via the communication cable 11 exiting from the electronic card SR.

[0056] The block diagram of figure 3 schematically represents the sequential steps (201 to 207) of the update procedure of the operating parameters of the hydrogen boiler C; such procedure provides for the following steps, following the structural adaptation operations performed with the steps 101 to 105:

[0057] - step 201: connecting the electronic card SR of the retrofit kit R and the main electronic card SC of the boiler via the communication cable 11;

[0058] - step 202: powering both the electronic cards SR and SC, preferably with mains voltage;

[0059] - step 203, A: the electronic card SR of the retrofit kit R powers the microprocessor of the main electronic card SC with a predefined voltage, for example 3.3 V;

[0060] - step 204: the electronic card SR performs a reading attempt of the main electronic card SC; if the reading is correct, the electronic card SR acquires the information that the power supply with a predefined voltage, for example 3.3 V, is indeed the right one, and the procedure continues with step 205; otherwise, if the reading is unsuccessful, the electronic card SR of the retrofit kit R modifies the power supply of the microprocessor of the main electronic card SC, by providing an updated voltage, for example 5 V (step 203 ,B);

[0061] - step 205: the electronic card SR acquires the data contained in the main electronic card SC, saving it in a temporary memory; such data comprises information necessary to the unique identification of the main electronic card SC, including at least:

[0062] - the identification code of the main electronic card SC,

[0063] - the version of the software loaded,

[0064] - the nominal power of the boiler,

[0065] and optional information necessary for the acquisition of the parameters of the heating system of which the boiler being converted is part, including for example:

[0066] - the statistical indicators related to the hours and operating cycles of the boiler,

[0067] - the values of the setpoint temperatures of the primary heating circuit for the indoor heating and of the secondary circuit for the sanitary hot water; - the values of the duration of the post-ventilation and postcirculation cycles;

[0068] Ultimately, with such step 205, the electronic card SR of the retrofit kit R recognises the main electronic card SC and the data loaded therein, starting from the version of the software thereof, in order to understand the characteristics of the boiler.

[0069] 205 is also functional to a consistency check between the retrofit kit R and the nominal power of the boiler, in order to confirm that the installed kit is actually suitable for the boiler: in case of installation of an incorrect kit, the update procedure of the operating parameter is interrupted with the issue of an error alert, for the necessary checks by a technician.

[0070] - step 206: based on the unique identification performed in step 205, the software of the electronic card SR of the retrofit kit R updates the software of the main electronic card SC of the boiler; such update comprises, at least the instruction to disable the part relating to the “safety” functions (see the following step 207); preferably, the software update also comprises reprogramming the parameters relating to the “comfort” functions of the boiler, while the parameters relating to the “safety” functions remain unchanged;

[0071] - step 207 : the updated software on the main electronic card SC disables the part relating to the “safety” functions stored therein, by activating the communication with the part relating to the “safety” functions present in the electronic card SR of the retrofit kit R.

[0072] Upon completion of such update procedure of the operating parameters thereof, the hydrogen boiler C, equipped with the retrofit kit R, is capable of operating in accordance with the software instructions relating to the “safety” functions contained in the electronic card SR of the retrofit kit R and in accordance with the software instructions relating to the “comfort” functions present in the main electronic card SC.

[0073] As is well known in the heating industry, “safety” functions of a boiler means the instructions and parameters stored on an electronic card for the management and control of critical safety -related operations: by way of a non-limiting example, such operations may comprise the ignition and steady-state operation of the burner, the regulation and control of the gas valve and fan to obtain the correct ratio of the air-gas mixture and the regulation of the operating power of the burner. In the boiler C comprising the retrofit kit R according to the invention, the “safety” functions stored in the electronic card SR mainly concern the regulation of parameters such as the lambda value of the air-gas mixture and the control of the presence of a flame; but, more generally, they comprise all those instructions aimed at achieving a safe combustion of hydrogen in order to prevent flashbacks, explosions, and gas leaks.

[0074] The “comfort” functions of a boiler, on the other hand, should be understood as the instructions and the parameters stored on an electronic card for the management and control of operations related to meeting the user requirements, typically entered by means of a user interface: by way of a non-limiting example, such operations may comprise the settings of the water temperature values to be used in the primary heating circuit for the indoor heating and in the secondary heating circuit for the production of sanitary hot water.

[0075] In the boiler C comprising the retrofit kit R according to the invention, the “comfort” functions stored in the main electronic card SC primarily concern the regulation of parameters such as the setpoint temperature value of the primary heating circuit for the indoor heating and the secondary circuit for sanitary hot water; as well as the regulation of the post-ventilation and post-circulation cycles at the end of an operating cycle of the burner 2.

[0076] In other words, the connection via a communication cable 11 between the electronic card SR of the retrofit kit R and the main electronic card SC of the boiler produces an automatic update of the operating parameters of the combustion unit, modifying the general operation thereof to allow it to be powered by pure hydrogen or high hydrogen content fuel gas.

[0077] With the sequential steps 201 to 207 of the update procedure of the boiler operating parameters, the retrofit kit R is configured as a fully plug&play monoblock combustion unit, i.e., ready for a quick and error-free retrofit installation on a standard boiler, meeting both the structural adaptation requirements (in accordance with steps 101 to 105) and those of software instruction reprogramming (in accordance with steps 201 to 207).

[0078] In contrast to what is known in the industry, there is therefore no need for a specialised technician to reprogram the main card SC or replace it, because it is sufficient that the communication cable 11 exiting from the electronic card SR is connected to the main electronic card SC to activate the update procedure described above, an operation that may also be easily performed by the same technician who deals with the previous step of structural installation of the kit. From the above description, it is clear that the system of the invention is able to achieve the underlying objects, in particular that of providing a reliable, quick and safe method for installing a retrofit kit R in a standard boiler in order to convert it into a hydrogen boiler C.

[0079] The pre-assembly of all the components of the retrofit kit R allows them to be preliminarily selected and assembled in production, subjecting them to extensive quality tests for the calibration and testing, thus ensuring that each of them operates correctly, both individually and integrated into the retrofit kit R, before the installation on the standard boiler.

[0080] This also enables to prevent a specific training for the installation technician, who simply needs to arrange the standard boiler for the insertion of the retrofit kit R and to perform the structural adaptation (according to steps 101 to 105) and software update procedure (according to steps 201 to 207), without resorting to any special equipment or knowledge.

[0081] The reduced number of components and operations for the conversion greatly reduces the possibility of human error by the installation technician: in particular, given the complete integration of the safety systems for managing and regulating the components thereof in the retrofit kit R, there is no need to connect / disconnect a plurality of cables and sensors, reducing the risk of incorrect configuration or failure to follow the connection procedures among the various components. Furthermore, the automatic start of the update procedure of the operating parameters of the hydrogen boiler C, following the simple connection between the electronic card SR of the retrofit kit and the main card SC of the boiler via the communication cable 11, eliminates the need for the installer to perform verification and testing procedures (already performed during production and during the assembly of the retrofit kit R), further speeding up the conversion process and minimising the risk of errors and malfunctions.

Claims

CLAIMS1. Retrofit kit (R) for the conversion of a standard gas combustion heating equipment into a gas combustion heating equipment (C) fuelled by pure hydrogen or by high hydrogen content fuel gas,said retrofit kit (R) comprising at least the following components:a closing door (1), provided with a sealing gasket (1.1), adapted to couple to the combustion chamber (22) of said heating equipment, said closing door (1) acting as a load-bearing structure for the remaining components of said retrofit kit (R);a preferably complete and modulable-power premixing burner (2), protruding from the inner face of said closing door (1);at least an ignition electrode (3);a mixing unit (7) for mixing combustion air and fuel gas, to form an air-gas mixture;a first feeding conduit (4) to said burner (2) of the air-gas mixture obtained in said mixing unit (7);a fan (6) configured to provide a combustion air flow to said mixing unit (7);a gas valve (9) configured to deliver fuel gas to said mixing unit (7) via a second feeding conduit (8);an electronic card (SR) for managing and regulating the combustion, control and safety parameters of said retrofit kit (R) and said combustion heating equipment (C);a communication cable (11) exiting such electronic card (SR), adapted to be connected to the main electronic card (SC) present on said heating equipment;said electronic card (SR) of said retrofit kit (R) being configured to perform at least one or more operations among:powering the microprocessor of said main electronic card (SC) with a predefined voltage,performing a reading attempt of said main electronic card (SC) and, if the reading is correct:acquiring the information that the predefined voltage is correct, acquiring and saving in a temporary memory the data contained in said main electronic card (SC), including at least an identification code, a version of the software loaded and the nominal power of said equipment;or, if the reading fails:modifying the power supply of the microprocessor of said main electronic card (SC) of the equipment, by providing an updated voltage.

2. Retrofit kit (R) according to claim 1,characterised in that it further comprises one or more sensor means (3.1) for detecting at least one combustion parameter.

3. Retrofit kit (R) according to any previous claim,characterised in that it further comprises a safety device for preventing the flashback, such as a non-retum valve (5) of the air-gas mixture, placed upstream of the first feeding conduit (4) of such mixture to the burner (2).

4. Retrofit kit (R) according to any previous claim,characterised in that it further comprises a hydrogen leak atmospheric sensor (10).

5. Retrofit kit (R) according to claim 1,characterised in that it comprises respective connection cables (3.S, 7.S, 6.S, 9.S) for the connection among said:at least an ignition electrode (3),mixing unit (7),fan (6),gas valve (9),and said electronic card (SC).

6. Retrofit kit (R) according to any claim 1 to 4,characterised in that it comprises respective connection cables (3.1.S, 10.S) for the connection between said:one or more sensor means (3.1) for the detection of at least one combustion parameter,an atmospheric sensor (10) for hydrogen leaks.

7. Gas combustion heating equipment (C), in particular a condensing gas boiler (C), comprising at least:a casing (20),a combustion chamber (22) with relative perimeter flange (21), a housing (23) obtained internally to said casing (20) and below said combustion chamber (22),characterised in that it comprises the retrofit kit (R) according to any claim 1 to 6,said combustion chamber (22) being adapted to accommodate the burner (2) of said retrofit kit (R) and said housing (23) being adapted to house the components that are supported by the outer face of the closing door (1) of said retrofit kit (R).

8. Use of a retrofit kit (R) according to any claims 1 to 6 for the conversion of a standard gas combustion heating equipment into a gas combustion heating equipment (C) fuelled by pure hydrogen or high hydrogen content fuel gas, in particular into a condensing gas boiler (C).

9. Procedure for the conversion of a standard gas combustion heating equipment into a gas combustion heating equipment (C) fuelled by pure hydrogen or high hydrogen content fuel gas, in particular into a condensing gas boiler (C), by installing the retrofit kit (R) of the claims 1 to 6, said procedure comprising the following steps:step 101: removing the components to be replaced from the standard gas combustion heating equipment;step 102: inserting the burner (2) of the retrofit kit (R) into the combustion chamber (22) of the equipment;step 103: fixing the closing door (1) of the retrofit kit (R) to the perimeter flange (21) of said combustion chamber (22);step 104: placing the components of the retrofit kit (R) supported by the outer face of said closing door (1) in the housing (23), located below and outside the combustion chamber (22);step 105: attaching the connections for feeding fuel gas and combustion air to the gas valve (9) and to the fan (6) of said retrofit kit (R);step 201 : connecting the electronic card (SR) of the retrofit kit (R) to the main electronic card (SC) of the equipment, via the communication cable (ii);step 202: powering said electronic cards (SR, SC);step 203. A: powering the microprocessor of said main electronic card (SC) of the equipment with a predefined voltage via said electronic card (SR) of the retrofit kit (R);step 204: performing a reading attempt of said main electronic card (SC) by means of said electronic card (SR) of the retrofit kit (R): in case of a correct reading, said electronic card (SR) of the retrofit kit (R) acquires the information that the power supply with predefined voltage is correct; in case of a failed reading, performing step 203. B in which said electronic card (SR) of the retrofit kit (R) modifies the power supply of the microprocessor of said main electronic card (SC) of the equipment, providing an updated voltage;step 205: acquiring and saving by said electronic card (SR) of the retrofit kit (R) the data contained in said main electronic card (SC) of the equipment, including at least:the identification code,the version of the software loaded,the nominal power of the equipment;step 206: updating the software of said main electronic card (SC) of the equipment via the software of said electronic card (SR) of the retrofit kit(R);step 207: using the software updated with the step 206, disabling by said main electronic card (SC) of the equipment the part of software related to the “safety” functions stored therein, activating the communication with the part of software relating to the “safety” functions contained in said electronic card (SR) of the retrofit kit (R).

10. Procedure according to claim 9,characterised in thatsaid step 205 optionally provides for the further acquisition, by said electronic card (SR), of the retrofit kit (R) of the parameters of the heating system of which the gas combustion heating equipment is part, including for example:the statistical indicators relating to the hours and operating cycles of said equipment,the values of the setpoint temperatures of the primary heating circuit for the indoor heating and of the secondary circuit for the sanitary hot water;the values of the duration of the post-ventilation and postcirculation cycles.

11. Procedure according to claim 9,characterised in thatsaid step 205 further provides for a consistency check between said retrofit kit (R) and the nominal power of the equipment.

12. Procedure according to claim 9,characterised in thatsaid step 206 also provides for updating the part of software relating to the “comfort” functions of the equipment contained in said main electronic card (SC).

13. Procedure according to any claims 9 to 12,characterised in thatsaid gas combustion heating equipment (C), in particular condensing gas boiler (C), whereon said retrofit kit (R) is installed, operates in accordance with the software instructions relating to the “safety” functions contained in said electronic card (SR) of the retrofit kit (R) and in accordance with the software instructions relating to the “comfort” functions contained in said main electronic card (SC).

Images