Method for controlling a boiler and a boiler

Abstract

The aim of the present invention is a control method for monitoring the efficiency state of components of a primary circuit (100) of a gas boiler (1), said components comprising a circulation pump (30), a primary heat exchanger (10), a secondary heat exchanger (20) on the primary side. Said method comprises a first partial method M.dhw suitable for signalling the degradation of one of said components of said primary circuit (100) as a consequence of the drop in the flow rate Q of the circulation in said primary circuit (100). Said method also envisages a second partial method M.hea (or, alternatively, method M.hea.bis) which is able to indicate whether the component actually responsible for said degradation of said primary circuit (100) is said secondary heat exchanger (20) on the primary side or one of said circulation pump (30) and said primary heat exchanger (10).

Description

TECHNICAL FIELD

[0001] The aim of the present invention is a control method for monitoring the efficiency of the components of the primary circuit of a gas boiler and for issuing a warning signal if the efficiency varies beyond a certain limit value, indicating that the components require maintenance.

[0002] In particular, the present invention includes in the field of gas boilers, in particular condensing boilers, suitable for producing hot water for room heating and sanitary use. BACKGROUND

[0003] As is known, a gas boiler comprises a heating water circuit (primary circuit) and a domestic water circuit (DHW circuit). Each of the two circuits has its own heat exchanger, respectively a "primary exchanger" and a "secondary exchanger".

[0004] In the primary heat exchanger, the heat coming from the burner flame is transferred to the heating water (hereinafter referred to as "heat transfer fluid"); in the secondary heat exchanger, on the other hand, the heat is transferred from the hot heat transfer fluid circulating in the primary circuit to the cold domestic water circulating in the domestic circuit.

[0005] As is also known, the high temperatures reached by the heat transfer fluid are the cause of the formation of limescale and the clogging of the components of the primary circuit, due to the precipitation of salts (mainly calcium sulphate) and impurities in colloidal form (usually iron oxides, bacteria, algae, sludge) on the internal surfaces of the pipes and heat exchangers.

[0006] Over time, these formations cause an unwanted increase in the surface frictional resistance to the flow of water in the pipes, to the point of risking to obstruct the passage of the water itself, while in the heat exchangers they also reduce the heat transfer, reducing the efficiency and jeopardizing the operation of the entire plant.

[0007] It is therefore necessary to periodically check the functioning of these components and to maintain them before they break down or cause irreparable damage to the boiler.

[0008] The prior art documents EP2966367 and JP2004116942, which relate to systems using heat pumps and heat pump water heaters respectively, describe a method for detecting anomalies that can occur due to clogging and limescale deposits based on controlling the flow rate of the liquid circulating in the heat exchanger, in which a refrigerant flows and transfers heat to the water used by the user.

[0009] However, in both patents, there is a single component, i.e. the heat exchanger equipped with the heat pump, which is prone to degradation over time; on the other hand, in heating systems based on the use of gas boilers, it is necessary to control a greater number of components in the primary circuit, all of which can lose efficiency over time. SUMMARY

[0010] The present application aims to overcome this inconvenience, providing a method and a relative control device to monitor the efficiency status of the components of the primary circuit of a boiler, in particular the primary heat exchanger and the secondary heat exchanger and the circulation pump.

[0011] Another purpose of the present application, at least in some of its variants, is to indicate a method that operates effectively using the components and devices already present in a typical gas boiler, without having to resort to additional devices or incurring additional costs.

[0012] Another purpose of the present application, at least in some of its variants, is to indicate means to signal, by means of a warning system, the need for maintenance of the boiler components being monitored, thus improving the friendliness of the user.

[0013] These and other purposes are achieved, according to the present application, by a control method for monitoring the status of the components of the primary circuit of a gas boiler, as will become clear hereinafter. Other purposes are also achieved by the additional characteristics of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0014] Other characteristics of the present application will become more apparent from the following description of a preferred embodiment thereof, illustrated by way of non-limiting example only and in accordance with the present application, in the attached drawings wherein:

[0015] - Figure 1 a hydraulic diagram of a typical gas boiler is shown, in which the control method according to the present application can be implemented;

[0016] - Figure 2 a hydraulic diagram of the boiler of Figure 1 is shown, the control method according to the present application operating according to a first "DHW sanitary" mode;

[0017] - Figure 3 a hydraulic diagram of the boiler of Figure 1 is shown, the control method according to the present application operating according to a second "HEA heating" operating mode;

[0018] - Figure 4 a block diagram schematically outlining the first step of the control method according to the present application is depicted;

[0019] - Figure 5The block diagram illustrating the second step of the control method according to the present application is described according to a first variant,

[0020] - Figure 6 The block diagram illustrating the second step of the control method according to the present application is described according to a second variant. DETAILED DESCRIPTION

[0021] The preferred variants of the control method according to the present application and the features of the related boiler implementing the method described above are now described, using the reference numbers contained in the figures. It should be noted that the aforementioned numbers, although schematic, reproduce the elements of the present application according to the scale and spatial orientation between their dimensions, in accordance with the possible embodiments.

[0022] REFERENCE Figure 1 1 indicates a gas boiler, in particular a gas condensing boiler, inside which there are the components necessary for its operation, which are well known to those skilled in the art; here only those strictly relevant to the purposes of the present application are mentioned.

[0023] The boiler 1 comprises a primary circuit 100 and a secondary circuit 200, both intended to heat water through corresponding heat exchangers, i.e. a primary heat exchanger 10 for the heat transfer fluid (hereinafter referred to as "primary heat exchanger 10") and a secondary heat exchanger 20 for domestic water (hereinafter referred to as "secondary heat exchanger 20").

[0024] The reference 4 indicates a gas valve, which regulates the flow of gas through the gas inlet C, so that, after mixing with the combustion air regulated by the fan 5, it is fed to the burner 3 (located in the combustion chamber 2 which houses the primary heat exchanger 10).

[0025] This primary circuit 100 comprises:

[0026] - a return conduit 11 which, via an inlet E, conducts the heat transfer liquid coming from the heating system of the system (not shown) to the primary heat exchanger 10, where it is subjected to the hot combustion fumes produced by the aforementioned burner 3;

[0027] - the aforementioned primary heat exchanger 10, which, in the example of the preferred variant shown, is constituted by a spiral coil exchanger;

[0028] - a circulation pump 30 placed on the return conduit 11; preferably, as shown, the circulation pump 30 also comprises degassing means 31 for processing the air bubbles formed in the heat transfer fluid;

[0029] - a supply conduit 12 of the heat transfer fluid, which, starting from the primary heat exchanger 10, is sent, via an outlet A, to the heating body of the heating system (hereinafter referred to as "system"),

[0030] - a bypass circuit 50, provided with calibrated spring check valves 51 according to the prior art; the known use of the bypass circuit 50 is to open it in order to make up the flow rate of the heat transfer fluid when this flow rate, circulating in the primary circuit 100, is reduced below a certain value due to the pressure drop in the heating system;

[0031] - a water filling valve 60, a water draining valve 61, a safety valve 62, all preferably according to the prior art.

[0032] Figure 3 The path of the heat transfer fluid just described is indicated more clearly with arrows and shows the operation of the boiler 1 in the "HEA room heating" operating mode (from now on "HEA mode").

[0033] The primary circuit 100 also comprises an inlet duct 21 deriving from the supply duct 12, suitable for making the heat transfer fluid flow towards the secondary heat exchanger 20 and then out of the latter by means of a return duct 22, making the fluid return to the return duct 11 of the primary circuit 100.

[0034] When the heat transfer fluid does not follow the path of the HEA operating mode, but is diverted through the aforesaid inlet duct 21 and return duct 22 through the secondary heat exchanger 20, the boiler operates in the "DHW domestic hot water heating" operating mode (from now on "DHW mode"), as indicated by the arrows in Figure 3 Figure 2

[0035] The secondary circuit 200 comprises:

[0036] - a cold water supply duct 23 which enters the secondary heat exchanger 20 through the inlet D, which is heated by the aforesaid inlet duct 21 and return duct 22 of the primary circuit 100, to produce domestic hot water, which is sent to the user through the outlet B by means of a return duct 24;

[0037] - the aforesaid secondary heat exchanger 20, generally of the plate type.

[0038] The reference 40 indicates an electrically operated three-way switching valve (from now on simply "three-way shutter valve 40"), the opening and closing of which determines the operation of the boiler 1 in the DHW or HEA mode.

[0039] In such a DHW mode:

[0040] - the circulation pump 30 is normally maintained at maximum speed,

[0041] - the three-way shutter valve 40 diverts the flow of the primary circuit 100 towards the secondary heat exchanger 20.

[0042] In the HEA mode:​​

[0043] - the rotation speed of the circulation pump 30 is variable according to requirements,

[0044] - the three-way flapper valve 40 diverts the flow of the primary circuit 100 to the heating body of the system, bypassing the secondary heat exchanger 20, via the outlet A.

[0045] Of course, in both cases the heat output depends on the required heat output.

[0046] Typically, at the end of the HEA mode, there is a third transitional operating mode, hereinafter referred to as post-circulation mode (hereinafter "post_HEA"), in which the three-way flapper valve 40 switches to the DHW mode: the burner 3 is switched off and the heat transfer fluid continues to circulate in short time intervals, as known to the person skilled in the art, in order to complete the processing of the heat of thermal inertia accumulation.

[0047] For the purposes of the method of the present application, the post_HEA mode is entirely equivalent to the measurement carried out in the DHW mode.

[0048] The control unit of the boiler 1, hereinafter simply "control unit 70", is indicated schematically by 70.

[0049] In the hydraulic scheme just described, the components of the boiler 1, which are crossed by the high-temperature heat transfer fluid, in particular the circulation pump 30, the primary heat exchanger 10, the secondary heat exchanger 20 (on the primary side, i.e. the side connected to the inlet and return conduits 21, 22 of the primary circuit 100), are very susceptible to efficiency reduction due to impurities deposition and formation of calcareous crusts.

[0050] The control method of the present application aims to monitor the efficiency status of these components, using the value of the flow rate Q of the heat transfer fluid circulating in said primary circuit 100 as a representative signal of the efficiency loss.

[0051] The value of said flow rate Q can be measured by known devices, such as flow switches or other types of flow sensors (not shown in the figures) present on said primary circuit 100, capable of transmitting a signal representative of said flow rate Q.

[0052] Alternatively or additionally, the value of the flow rate Q can also be determined indirectly, by means of sensors that detect a set of one or more physical quantities (for example, those shown below) from which the flow rate Q itself can be calculated.

[0053] However, according to a preferred variant of the application, the value of the flow rate Q is provided by a signal emitted by a so-called intelligent circulation pump 30 (hereinafter referred to as "intelligent pump"), without the need to provide a dedicated flow rate sensor; in other words, the intelligent pump already integrates sensing means at least sufficient to infer the flow rate Q by means of calculations and / or consultation of a pre-stored data table.

[0054] The intelligent pump itself can also integrate the necessary processing means to determine the value of said flow rate Q.

[0055] The intelligent pump is a circulator able to exchange information bi-directionally with the control unit 70 of the boiler, which, in addition to communicating to the circulation pump 30 the speed at which it must operate, can also query it to receive specific information about its status, for example:

[0056] - the electric power drawn,

[0057] - the number of revolutions,

[0058] - the operating status (active, standby, error),

[0059] - and, precisely, the flow rate Q resulting from the processing of the previous parameters.

[0060] According to a preferred variant of the application, said value of the flow rate Q is an indirect quantity, calculated as a function of the electric power consumption and the number of revolutions detected and transmitted by the intelligent pump 30.

[0061] As mentioned, it is still understood that, in order to implement the method described herein, when the boiler 1 comprises a circulation pump 30 of the traditional type, instead of an intelligent pump, the value of the flow rate Q can also be obtained through a temporary flow rate sensor.

[0062] As for the processing means necessary to determine said value of the flow rate Q, it is preferred that they reside in the control unit 70, which, for each type of boiler 1, does not need to be customized in any way with respect to the intelligent pump. However, the position of such processing means is completely irrelevant from an inventive point of view and is technically equivalent. Hereinafter, the discussion of the application will assume that all the processing power is attributed to the control unit 70, or, more generally, by "control unit 70" we mean the entire set of data processing elements necessary for the implementation of the method according to the application, which are united or distributed in several sub-devices.

[0063] The control method will now be described in detail in step order with reference to the block diagram of Figure 4 .

[0064] The first part of the method, hereinafter referred to as "method M.dhw", is intended to indicate whether, during the Q-r values of the flow rate Q of the primary circuit 100 in the repeated reading of the DHW mode, there is a reduction of the flow rate Q (hereinafter referred to as "flow rate Q.dhw") delivered by the circulation pump 30 below values considered unacceptable. These reductions are indicative of a degradation of the efficiency of one of the components of the primary circuit 100, in particular of the primary heat exchanger 10 and / or of the secondary heat exchanger 20 (primary side) and / or of the circulation pump 30.

[0065] The preferred variant of the first part of the method M.dhw described herein, assumes that the manufacturer has stored in the control unit 70 at least:

[0066] - a reference value Q.dhw-rif, which the flow rate Q generated by the circulation pump 30, in this case "flow rate Q.dhw", must have when the boiler 1 is in the DHW mode, this constant and considered optimal reference value Q.dhw-rif;

[0067] - a threshold value AQ.dhw-rif, consisting of the amount of reduction of the Q-r value detected with respect to the reference value Q.dhw-rif, below which the Q-r value indicates an anomalous flow rate Q.dhw;

[0068] - a measure Fl.max of anomalous Q-r values, which is considered acceptable before deciding that the detected anomaly is real and irreversible, rather than due to a reading error or to an accidental and temporary situation (as a non-limiting example, this Fl.max value is equal to 10).

[0069] The threshold value AQ.dhw-rif is predetermined by the manufacturer on the basis of laboratory tests and / or periodic monitoring during the actual use of the boiler 1 and / or other elements deduced by a person skilled in the art with reference to the specific type of boiler 1 and system.

[0070] Preferably, said threshold value AQ.dhw-rif is chosen so as to accept deviations between the flow rate value Q-r and the preferred value Q.dhw-rif of between 20% and 50%, even more preferably between 20% and 25%.

[0071] However, this threshold value AQ.dhw-rif can be modified by storing a new value AQ.dhw-rif in the control unit 70; for example, if an additive is added to the heat transfer fluid, causing a change in the value of the monitored flow rate Q.dhw, this modification is appropriate.

[0072] Method M.dhw

[0073] Since the post_HEA mode can be set to the boiler 1 at any time, interrupting the HEA mode, without causing significant disturbances to the user, in case it is not already in the DHW mode, when it is necessary to read the Q-r value, it can be repeated by the control unit 70 at substantially determined time intervals At, placing the boiler 1 in the post_HEA mode. However, on the other hand, the final degradation to be detected is a slow process, whose detection does not require frequent readings within narrow or forced time intervals, therefore, unless otherwise specified below, the method should carry out its steps at indeterminate time intervals At each time the boiler 1 is naturally in the DHW and / or post_HEA mode. Since the DHW mode and the post_HEA mode are technically equivalent for the purposes of the present method, in the method description the latter will be disregarded, "DHW mode" being understood as "DHW mode" or "post_HEA" mode.

[0074] Control method M.dhw

[0075] Step M.dhw_1

[0076] In this step, the monitoring of the Q-r value of the flow rate Q.dhw of the heat transfer fluid circulating in the boiler 1 in the DHW mode is performed; this step M.dhw_1 comprises the following steps:

[0077] - the control unit 70 initializes a memory location named "Flag" with the value Fl = 0;

[0078] - when the boiler 1 is in the DHW mode, the control unit 70 receives or calculates the Q-r value of the flow rate Q.dhw. This Q-r value is preferably measured after a certain period of time (for example 10 seconds) after the start of the DHW mode, so that it can represent a stable flow rate value;

[0079] - this Q-r value is recorded in the memory of the control unit 70 as a stable value Q-r.0;

[0080] - we proceed to step M.dhw_1.1.

[0081] Step M.dhw_1.1

[0082] In this step, it is ensured that the Q-r value read is a stable value.

[0083] The measurement of the Q-r value obtained in step M.dhw_1 is repeated after a preferred time interval Δt of a few seconds to allow the heat transfer fluid to expel any air bubbles that obstruct the circulation, and the new value obtained Q-r.1 is compared with the stable value Q-r.0 stored after the previous reading:

[0084] - if it is the result Q-r.1 > Q-r.0, this case represents that after the previous primary measurement, air bubbles that obstruct the circulation of the heat transfer fluid have been expelled from the primary circuit 100, the value Q-r.0 is updated in the control unit 70 by setting Q-r.0 = Q-r.1 ; i.e. the Q-r value of the flow Q.dhw is updated to Q-r.1, and we return to the beginning of this step M.dhw_1, checking whether the flow stabilization process is still in progress;

[0085] - otherwise, if the new value Q-r.1 does not exceed Q-r.0 (i.e. if Q-r.1 < Q-r.0; stable flow index Q.dhw):

[0086] - in the control unit 70, the previous stable value Q-r.0 is saved in the memory as the Q-r value,

[0087] - and we proceed to the next step M.dhw_1.2, comparing this stored Q-r value of the flow Q.dhw with the reference value of Q.dhw-rif stored.

[0088] Step M.dhw_1.2

[0089] In this step, it is determined whether the read Q-r value shows a decrease, a transitory or persistent anomaly:

[0090] - if the deviation between the two values Q.dhw-rif and Q-r does not exceed a predetermined threshold AQ.dhw-rif (i.e. if Q.dhw-rif - Q-r < AQ.dhw-rif), the control unit 70 interrupts the control method by terminating the monitoring of the Q.r value of the flow Q.dhw and goes to the final step END.dhw_2, where the cycle ends, ready to periodically repeat the control method “M.dhw” starting from step M.dhw_1 ;

[0091] - on the contrary, if this decrease of the last Q-r value of the flow Q.dhw exceeds the threshold AQ.dhw-rif (Q.dhw-rif - Q-r > AQ.dhw-rif), it means that the Q-r value of the flow Q.dhw is considered anomalous and then:

[0092] - the Fl value stored in the flag memory location is increased by one unit,

[0093] - the stored Fl value is compared with a predetermined Fl.max value, and

[0094] - if Fl = Fl.max, it is concluded that the detected anomalous condition is persistent, since a succession of Fl.max times and anomalous Q-r values has been detected, and we proceed to step END.dhw_1,

[0095] - otherwise, we proceed to step END.dhw_2.

[0096] Step END.dhw_2

[0097] The control unit 70 stops the cycle of the method M.dhw, but is ready to repeat it starting from step M.dhw_1:

[0098] - periodically, within a predetermined and settable period of time, which can mean, for example, immediately or instead after a few months,

[0099] - and / or at any time, at the command of the user or of the technical assistance service (hereinafter "SAT").

[0100] Step END.dhw_1

[0101] In this step, the control unit 70 is provided to emit an alarm signal W.dhw, preferably a visual and / or acoustic signal perceivable by the user, provided by said control unit 70 to the display screen of the boiler 1, and / or to the connection service of the user, and / or to the SAT, via an email communication.

[0102] Once step END.dhw_1 has been performed, the boiler 1 continues its normal operation and its operation is not necessarily interrupted. However, the alarm signal W.dhw is an important fact for the user and / or for the SAT that the efficiency status of one of the components of the primary circuit 100 has deteriorated. This alarm signal W.dhw is therefore a useful element that can allow control and maintenance activities to be carried out on the circulation pump 30 and / or on the primary heat exchanger 10 and / or on the secondary heat exchanger 20 (primary side) before the boiler 1 presents major problems, no longer able to operate adequately or in any case to reach a satisfactory efficiency.

[0103] At the end of the control method M.dhw, if the alarm W.dhw has not been issued, this means that no persistent abnormal condition has been detected in said components of the primary circuit 100 of the boiler 1, and there is no need for further checks. On the other hand, if the alarm W.dhw has been issued, this indicates that there is a problem with one of these components, and almost certainly with only one: the circulation pump 30, the primary heat exchanger 10, the secondary heat exchanger 20 on the primary side (almost never more than one, since it is not possible that, during a single execution of the M.dhw method, irreversible abnormal conditions arise in several elements, which were all normal in the previous execution of the same method).

[0104] In other words, if this control method M.dhw is periodically executed, it anticipates that one of the components 30, 10, 20 of the primary circuit 100 reaches a state of degradation before the others of them do.

[0105] The time interval between two successive executions of the M.dhw method is preferably determined by the manufacturer on the basis of its experience and the possible working conditions of the boiler 1, it being understood that successive execution is desirable since it does not involve any waste of energy or disturbance to the user.

[0106] It can therefore be reasonably said that, if it is periodically repeated, the method M.dhw according to the application indicates that only one of the three components "circulation pump 30, primary heat exchanger 10, secondary heat exchanger 20 (primary side)" reaches a state of degradation requiring maintenance, although it is not certain which of the three components this degradation actually occurs in.

[0107] At this point, it can be useful to further refine the monitoring, by executing the subsequent steps of the method according to the application, able to distinguish which component of the primary circuit 100 actually caused the significant drop in the flow rate Q of the heat transfer fluid.

[0108] This control method (hereinafter "method M.hea") is carried out when the boiler 1 is in the HEA mode, as shown in Figure 3 i.e. the three-way flapper valve 40 is switched so as to disconnect the secondary heat exchanger 20 from the primary circuit 100, closing the return conduit 22 of said primary circuit 100; the heat transfer fluid is then sent to the heating body of the system via the supply conduit 12 and the outlet A, to return to the primary heat exchanger 10 via the inlet E and the return conduit 11.

[0109] As summarized in the block diagram in Figure 5 , the method M.hea involves measuring the value of the flow rate Q.hea of the heat transfer fluid circulating in the boiler 1 in the HEA mode. Note that the value of the flow rate Q.hea varies as a function of the state of the boiler 1 and of the heating body network.

[0110] This flow value Q.hea is then compared with a flow value Q.hea-rif, which represents the flow of heat transfer fluid circulating in the boiler 1 in HEA mode during the first start-up of the boiler 1, installed or subsequently set by the technician during a calibration step of the system (hereinafter both referred to as "calibration step").

[0111] This flow value Q.hea-rif is therefore a reference value measured and stored in the control unit 70 during a calibration step of the system, prior to the application of the method M.hea, calibrated by the installer under standard conditions, i.e. with all the heating bodies open and the bypass circuit 50 closed.

[0112] This flow value Q.hea must therefore be measured during the execution of this method M.hea under the same operating conditions of the calibration step of the system described above, in order to make a meaningful comparison of the two flow values Q.hea and Q.hea-rif (step M.hea_1), i.e.:

[0113] - all the heating bodies are open (hence, after checking that some of them are not closed due to the selection of the user or the automatic activation of any thermostatic valve),

[0114] - and the bypass circuit 50 is closed.

[0115] The activation of the bypass circuit 50 would alter the flow value Q.hea, making it impossible to make a uniform comparison with the flow value Q.hea-rif, said bypass circuit 50 being normally excluded in three ways:

[0116] - by automatically setting the speed of the circulation pump 30 to a value normally between 60% and 85% of the maximum speed, so that this bypass circuit 50 is not open;

[0117] - or by manually closing said bypass;

[0118] - or by automatically closing it by means of an electromechanical actuator controlled by the control unit 70.

[0119] The execution of this method M.hea is preferably carried out by a specialized technician, such as the installer, taking into account the operating conditions described above.

[0120] However, it is also conceivable that this step of the method M.hea can be carried out with the input of the user, providing appropriate warning procedures and indications so that the boiler 1 is previously placed in the same operating conditions of the calibration step, in which the flow value Q.hea-rif is measured and stored.

[0121] An alternative method is to calibrate the system by completely bypassing the heating system, by coupling the outlet A to the inlet E by means of a bypass pipe (not shown in the drawings except for the preferred variant, and hereinafter referred to as "calibration bypass"), which provides a pressure drop that substantially simulates the pressure drop of the actual heating system. Preferably, such a calibration bypass has one or more of the following characteristics, some of which are obviously alternative:

[0122] - the pressure drop is adjusted by means of a calibratable throttle valve, equipped with a knob that regulates the pressure drop;

[0123] - this knob is graduated, so that a preset pressure drop can be safely set, which is similar to the pressure drop of the heating body circuit that the boiler 1 can serve;

[0124] - it consists of a pressure gauge, which is installed by the installer during calibration, and then again during the subsequent checks using the method M.hea;

[0125] - as an alternative to the previous paragraph, it is present in an element permanently installed in the boiler 1 and can be made operational by manually or remotely controlling the opening of a shut-off valve.

[0126] - it is present (see Figure 1 ) in a "bypass simulator 55" coinciding with the bypass circuit 50, according to the present application, in which:

[0127] - the spring check valve 51 can be forced open manually or remotely,

[0128] - the calibratable throttle valve 52 can be manually or remotely controlled to put the bypass circuit 50 into calibration bypass mode,

[0129] - the two manually or remotely controllable shut-off valves 53 and 54, which exclude the circulation of the heat transfer fluid to the heating bodies.

[0130] As far as the M.hea method is concerned, it is absolutely irrelevant whether the boiler 1 enters the HEA mode with the actual heating circuit in the state of the previous calibration step, or uses the calibration bypass just described in the different variants; the only important thing is that, in this method M.hea, the real or simulated heating system has the same pressure drop as the one in which the previous calibration step was performed, and this pressure drop preferably represents the normal operating conditions.

[0131] Control method M.hea

[0132] This method M.hea can be performed after the step END.dhw_1 of the previous method M.dhw, which emits the alarm signal W.dhw, to further identify which component in the primary circuit 100 caused the drop in the flow of heat transfer fluid.

[0133] As mentioned above, this method M.hea foresees the measurement of the value of the flow rate Q.hea of the heat transfer fluid circulating in the boiler 1 in HEA mode, the pressure losses of the system (actually through the bypass circuit 50, or simulated through the bypass simulator 55) being substantially the same as in the previous calibration step in HEA mode, during which the value of the flow rate Q.hea measured is equal to the reference value Q.hea-rif.

[0134] As mentioned above, this method M.hea foresees the measurement of the value of the flow rate Q.hea of the heat transfer fluid circulating in the boiler 1 in HEA mode, the pressure losses of the system (actually through the bypass circuit 50, or simulated through the bypass simulator 55) being substantially the same as in the previous calibration step in HEA mode, during which the value of the flow rate Q.hea measured is equal to the reference value Q.hea-rif. Figure 5 As outlined in the block diagram in

[0135] Step M.hea_1

[0136] In this step, the flow rate Q.hea is measured, and:

[0137] - if the measured value Q.hea is the same as the flow rate value Q.hea-rif (Q.hea = Q.hea-rif), the degraded component of the primary circuit 100 is the secondary heat exchanger 20 on the primary side, and the method continues with the step END.hea_1,

[0138] - otherwise (i.e. if Q.hea ≠ Q.hea-rif), the method goes to the step END.hea_2.

[0139] Step END.hea_1

[0140] In this step:

[0141] - the condition W.20 is signalled, indicating that the secondary heat exchanger 20 on the primary side is the component responsible for the substantial drop in flow rate Q.dhw indicated by the alarm signal W.dhw in the previous step END.dhw_1;

[0142] - the procedure of the method M.hea is terminated.

[0143] Step END.hea_2

[0144] In this step:

[0145] - the condition W.30-10 is signalled, indicating that one of the circulation pump 30 or the primary heat exchanger 10 is responsible for the substantial drop in flow rate Q.dhw indicated by the alarm signal W.dhw in the previous step END.dhw_1 of the method M.dhw;

[0146] - the procedure of the method M.hea is terminated.

[0147] Said conditions W.20 and W.30-10 can consist in visual and / or acoustic signals provided by the control unit 70 to the display of the boiler 1 and / or in connection services provided to the user and / or in email communications to the SAT.

[0148] Therefore, in both conditions W.20 and W.30-10, the control method M.hea provides useful information to further identify in which components of the primary circuit 100 the degradation of the efficiency condition occurs:

[0149] - in the case of condition W.20, it can be affirmed that the responsible component is the secondary heat exchanger 20 on the primary side;

[0150] - however, in the case of condition W.30-10, there is still some uncertainty between the circulation pump 30 and the primary heat exchanger 10, which must be checked both with the intervention of technical assistance.

[0151] However, in a variant of the application, said circulation pump 30 consists of a smart pump, condition W.30-10 can be combined with further information requested by the control unit 70 from said smart pump, including information representative of its operating condition, which makes it possible to assess whether the component of the primary circuit 100 that is the subject of the reduction of the flow value Q.dhw is actually the smart pump or the primary heat exchanger 10: in such a case, if the control unit 70 deduces from the information integration provided by the smart pump that the component that degrades is actually the primary heat exchanger 10 or the circulation pump 30, respectively, the control method M.hea can continue to emit the signal W.10 or W.30.

[0152] Control method M.hea.bis

[0153] As an alternative to the above control method M.hea, as said normally performed by a professional technician, an alternative method can be envisaged, which is however performed automatically by the control unit 70 and is always aimed at further identifying which component in the primary circuit 100 is responsible for the drop in the flow of heat transfer fluid that caused the emission of the alarm signal W.dhw in step END.dhw_1 of the previous method M.dhw.

[0154] Like the method M.hea, this second variant of the control method (hereinafter called "method M.hea.bis") is carried out when the boiler 1 is in the HEA mode, i.e. when the three-way flapper valve 40 is switched so as to disconnect the secondary heat exchanger 20 from the primary circuit 100, closing the return conduit 22 of said primary circuit 100. Figure 3

[0155] ​This method M.hea.bis is automatically performed by the control unit 70, provided that the speed of the circulation pump 30 is automatically set to a value preferably between 60% and 85% of the maximum speed, so that the bypass circuit 50 is not opened.

[0156] Furthermore, the method M.hea.bis described herein requires the control unit 70 to contain in its memory at least:

[0157] - the reference value Q.hea.bis-rif that the flow rate Q.hea delivered by the circulation pump 30 must have when the boiler 1 is in the HEA mode, which is considered optimal: this Q.hea.bis-rif value is usually equal to the value of the flow rate of the heat transfer fluid circulated during the calibration step of the system (when the boiler 1 is first installed or subsequently adjusted by the technician); alternatively, if the technician does not perform this calibration step, this Q.hea.bis-rif value is initially equal to 0 and is then replaced by the updated reference value following the first flow rate reading at the end of the first primary heat demand after the boiler 1 is installed: in both cases, said Q.hea.bis-rif reference value is periodically updated and, if in the subsequent periodic readings, it proves to be higher than the value previously stored, it is stored in the control unit 70 as it represents the Q.hea.bis-rif reference value that has stabilized due to the expulsion of the air bubbles from the heat transfer fluid;

[0158] - the threshold AQ.hea.bis-rif consisting of the decrease in the value of Q.hea.bis measured with respect to the Q.hea.bis-rif reference value.

[0159] This threshold AQ.hea.bis-rif is predetermined by the manufacturer on the basis of laboratory tests and / or periodic monitoring during the actual use of the boiler 1 and / or other elements inferred by the technicians of the sector with reference to the specific type of boiler 1 and system.

[0160] Preferably, the threshold AQ.hea.bis-rif is chosen so as to accept a deviation of the flow rate value Q.hea.bis from the preferred value Q.hea.bis-rif not exceeding 20%.

[0161] It is also possible to modify the above-mentioned reference value Q.hea.bis-rif by storing a new Q.hea.bis-rif value in the control unit 70, for example if an additive is added to the heat transfer fluid, causing a variation in the value of the monitored flow rate Q.hea.bis.

[0162] Similarly to the description of the method M.hea, the method M.hea.bis comprises the following steps (outlined in the block diagram of Figure 5 Figure 6 ​​

[0163] Step M.hea.bis_1

[0164] In this step, after the alarm signal W.dhw has been issued in the step END.dhw_1 of the previous method M.dhw, the monitoring of the detected value Q.hea.bis of the flow rate Q.hea of the heat transfer fluid circulating in the boiler 1 in the HEA mode is performed.

[0165] Through this step M.hea.bis_1, preferably performed at the end of the primary heat requirement after the alarm signal W.dhw has been issued as above, it is determined whether the value Q.hea.bis read in comparison with the reference flow rate Q.hea.bis-rif shows a decrease exceeding the predetermined threshold AQ.hea.bis-rif as above, and:

[0166] - if the deviation between the two values Q.hea.bis-rif and Q.hea.bis does not exceed this predetermined threshold AQ.hea.bis-rif (i.e. if Q.hea.bis-rif - Q.hea.bis <= AQ.hea.bis-rif), the degraded component of the primary circuit 100 is the secondary heat exchanger 20, and the method continues with the step END.hea-bis_1,

[0167] - otherwise (i.e. if Q.hea.bis-rif - Q.hea.bis > AQ.hea.bis-rif), the method goes to the step END.hea-bis_2.

[0168] Step END.hea.bis_1

[0169] In this step:

[0170] - the control unit 70 issues the signal of the condition W.20 indicating that the secondary heat exchanger 20 on the primary side is the component responsible for the significant decrease in the flow rate Q.dhw indicated by the alarm signal W.dhw in the previous step END.dhw_1 of the primary circuit 100;

[0171] - the procedure of the method M.hea.bis is terminated.

[0172] Step END.hea.bis_2

[0173] In this step:

[0174] - the control unit 70 issues the signal of the condition W.30-10 indicating that one of the circulation pump 30 or the primary heat exchanger 10 is responsible for the significant decrease in the flow rate Q.dhw indicated by the alarm signal W.dhw in the previous step END.dhw_1 of the method M.dhw;

[0175] - termination of the procedure of the method M.hea.bis.

[0176] Similarly to the control method M.hea, in this variant of the method M.hea.bis, the condition signals issued in the steps END.hea.bis_l and END.hea.bis_2 can consist of visual and / or acoustic signals provided by the control unit 70 to the display screen of the boiler 1 and / or of connection services provided to the user and / or of communications to the SAT via e-mail.

[0177] Similarly to the control method M.hea, in this case, when the smart pump is present, the signal condition W.30-10 can be combined with further information requested by the control unit 70 from said smart pump, including information representative of its operating state, which allows to assess whether the component of the primary circuit 100 that caused the reduction of the flow value Q.dhw is actually the smart pump or the primary heat exchanger 10: in such a case, if the control unit 70 deduces from the information provided by the smart pump integration that the degraded component is actually the primary heat exchanger 10 or the circulation pump 30, respectively, the control method M.hea can continue to issue the signal W.10 or W.30.

[0178] Obviously, many variants of the control method and of the related boiler 1 using said method are possible for the person skilled in the art, without however going beyond the innovative scope inherent in the inventive idea, as well as in the practical implementation of the present application, the various components described above can obviously be replaced by technically equivalent elements.

[0179] For example, the same control method can also be used for a boiler 1 without bypass circuit 50, in which case it is possible to leave the circulation pump 30 unregulated, or even allowed at maximum speed, even in the methods M.hea or M.hea.bis.

Claims

1. A method for controlling a boiler (1), said boiler (1) comprising: - a primary circuit (100) for the heating of a heat transfer fluid, said primary circuit (100) in turn comprising: - a combustion chamber (2) which houses a primary heat exchanger (10) and a burner (3), said burner (3) being provided with an air / gas mixture by a fan (5) and a gas valve (4), - a supply conduit (12) and a first return conduit (11) of said heat transfer fluid flowing in said primary circuit (100) are respectively adapted to direct said fluid to and from a heating body of a heating system by means of a circulation pump (30), - an inlet conduit (21) and a second return conduit (22) for deviating said heat transfer fluid in its primary side towards a secondary heat exchanger (20), - a secondary circuit (200) for the heating of sanitary water, comprising: - said secondary heat exchanger (20); - a supply conduit (23) and a third return conduit (24) respectively adapted to direct cold water to an inlet of a secondary side of said secondary heat exchanger (20) and to direct hot said sanitary water from said secondary side of said secondary heat exchanger (20) towards a user, - a three-way flapper valve (40) adapted to switch the path of said heat transfer fluid to: - via an outlet A towards said heating body of said heating system, in which case said boiler (1) is in a HEA operating mode to heat said fluid, - or towards said secondary circuit (200), in which said heat transfer fluid is deviated towards said secondary heat exchanger (20) in its primary side by means of said inlet conduit (21) and said second return conduit (22), in which case said boiler (1) is in a DHW operating mode to heat said sanitary water, - a control unit (70) adapted to manage the steps of said method and to exchange information with sensor means adapted to measure a flow rate Q of said heat transfer fluid flowing in said primary circuit (100), said method monitoring the efficiency status of said primary heat exchanger (10) and / or said secondary heat exchanger (20) in its primary side and / or said circulation pump (30) by means of a periodic control of a flow rate value of said heat transfer fluid flowing in said primary circuit (100), said flow rate value being provided by said sensor means and processed by said control unit (70), characterized in that, said method outputs a signal representative of a loss of efficiency of said primary heat exchanger (10) and / or said secondary heat exchanger (20) in its primary side and / or said circulation pump (30) when said flow rate value is lower than a reference flow rate value pre-stored in said control unit (70), said flow rate value and said reference flow rate value being provided by: - a flow meter or other equivalent type of flow sensor located on said primary circuit (100), - and / or a smart pump, - and / or sensor means which detect one or more physical quantities from which said flow rate value and said reference flow rate value are calculated, The method comprises a first partial method M.dhw, wherein: - the boiler (1) is in the DHW operating mode; - the circulation pump (30) is set to the maximum rotation speed; - the control unit (70) contains in the memory at least: - a reference flow value Q.dhw-rif, which represents the optimal flow of the boiler (1) in the DHW operating mode; - a threshold value AQ.dhw-rif, which comprises a detected reduction of the flow value Q-r with respect to the reference flow value Q.dhw-rif, which represents an anomalous reduction of the flow value, - a value Fl.max, which represents the maximum number of consecutive overpasses of the threshold value AQ.dhw-rif; - the reference flow value Q.dhw-rif is compared with the repeated reading of the reduction of the flow value in the primary circuit (100) of the boiler (1) in the DHW operating mode, and if: - the number of consecutive overpasses of the threshold value AQ.dhw-rif is equal to the value Fl.max, then the control unit (70) provides a final step END.dhw_1 for outputting an alarm signal W.dhw, which represents a loss of efficiency of the primary heat exchanger (10) and / or of the secondary heat exchanger (20) and / or of the circulation pump (30) on the primary side thereof, - otherwise, the control unit (70) provides a final step END.dhw_2, which stops the first partial method M.dhw and sets to periodically repeat it.

2. The method of claim 1, wherein, The boiler (1) is a gas condensing boiler.

3. The method according to claim 1, characterized in that the threshold value AQ.dhw-rif is pre-established by the builder of the boiler (1) according to laboratory tests and / or periodic monitoring during actual use and / or by a person skilled in the art through other elements.

4. The method according to any one of claims 1-3, characterized in that the threshold value AQ.dhw-rif can then be modified by storing a new threshold value AQ.dhw-rif in the control unit (70).

5. The method according to claim 4, characterized in that the threshold value AQ.dhw-rif comprises between 20% and 50% of the reference flow value Q.dhw-rif.

6. The method according to claim 5, characterized in that the value Fl.max, which represents the maximum number of consecutive overpasses of the threshold value AQ.dhw-rif, is equal to 10.

7. The method according to claim 6, characterized in that the first partial method M.dhw comprises a step M.dhw_1, wherein: - the control unit (70) initializes a flag memory position with the value Fl = 0. - said control unit (70) receives or calculates a flow value Q-r of said flow rate Q.dhw, wherein Q.dhw is the flow rate Q of the primary circuit in the DHW mode; - such flow value Q-r of said flow rate Q.dhw is recorded in said memory of said control unit (70) as a stable value Q-r.

0.

8. The method according to claim 7, characterized in that said flow value Q-r of said flow rate Q.dhw is received or calculated by said control unit after a time period from the start of said boiler (1) in said DHW operating mode.

9. The method according to claim 7, characterized in that said flow value Q-r of said flow rate Q.dhw is received or calculated by said control unit after 10 seconds from the start of said boiler (1) in said DHW operating mode.

10. The method according to any one of claims 7-9, characterized in that said first partial method M.dhw comprises, after said step M.dhw_1, a step M.dhw_1.1 wherein: - the measurement of said flow value Q-r of said flow rate Q.dhw is repeated after a time period At, obtaining a new value Q-r.1; - such new value Q-r.1 is compared with said stable value Q-r.0, and: - if such new value Q-r.1 is greater than said stable value Q-r.0: - said control unit (70) stores this new value Q-r.1, assuming it as a new stable value Q-r.0, representative of said flow value Q-r of said flow rate Q.dhw, - said control unit (70) repeats said step M.dhw_1.1; - otherwise, in said control unit (70), said stable value Q-r.0 is maintained in said memory to be representative of said flow value Q-r of said flow rate Q.dhw.

11. The method according to claim 10, characterized in that said first partial method M.dhw comprises, after said step M.dhw_1.1, a step M.dhw_1.2 wherein: - said flow value Q-r of said flow rate Q.dhw is compared with said reference flow value Q.dhw-rif, and if: - the difference does not exceed said threshold AQ.dhw-rif, said control unit (70) stops said first partial method M.dhw by providing said final step END.dhw_2; - the difference exceeds said threshold AQ.dhw-rif, said control unit (70): - increases by one unit the value Fl stored in said flag memory location, - compares said stored value Fl with said value Fl.max, and if: - Fl = Fl.max, said control unit (70) provides said final step END.dhw_1, determines a persistent anomaly and outputs said warning signal W.dhw, - otherwise, said control unit (70) stops said first partial method M.dhw by providing said final step END.dhw_2.

12. The method according to claim 11, characterized in that in said final step END.dhw_2, said control unit (70) is set to periodically repeat said first partial method M.dhw starting from said step M.dhw_1, periodically and settable in time and / or on command of a user or technical assistance service.

13. The method according to claim 11, characterized in that in said final step END.dhw_1, said control unit (70) provides the output of said warning signal W.dhw comprising a visual and / or acoustic signal perceivable by a user provided to a display of said boiler (1) and / or a connection service provided to a user and / or a communication to a technical assistance service via e-mail.

14. The method according to claim 13, characterized in that said first partial method M.dhw can be executed when said boiler (1) is in a post_HEA operating mode, wherein said burner (3) is just turned off at the end of said HEA operating mode.

15. The method according to claim 13, characterized in that said method comprises a second partial method M.hea after said final step END.dhw_1 of said first partial method M.dhw, wherein: - said boiler (1) is in said HEA operating mode; - said circulation pump (30) is set to a variable speed required; - said control unit (70) contains in said memory at least one reference flow value Q.hea-rif representing an optimal flow of said boiler (1) in said HEA operating mode during a calibration step of said heating system; - said reference flow value Q.hea-rif is compared with a flow value Q.hea of said boiler (1) in said HEA operating mode and of said heating system in the same operating mode flowing in said primary circuit (100), wherein said reference flow value Q.hea-rif has been stored in said control unit (70) and if: - said flow value Q.hea is equal to said reference flow value Q.hea-rif, then said control unit (70) provides a final step END.hea_1 determining that said degraded component of said primary circuit (100) is said secondary heat exchanger (20) in its primary side, - said flow value Q.hea is different from said reference flow value Q.hea-rif, then said control unit (70) provides a final step END.hea_2 determining that said degraded component of said primary circuit (100) is said primary heat exchanger (10) or said circulation pump (30).

16. The method according to claim 15, characterized in that said reference flow value Q.hea-rif is measured and stored in said control unit (70) in a calibration step occurring: - at the time of installation during the first start-up of said boiler (1), - or during a subsequent adjustment of said heating system by a technician, At the same time all said heating bodies are open and the bypass circuit (50) is closed.

17. The method according to claim 15, characterized in that, the reference flow value Q.hea_rif is measured in a calibration step, which occurs by means of a bypass duct of the heating system, which connects directly from the outlet A of the supply conduit (12) to the inlet E of the first return conduit (11) of the primary circuit (100) and is adapted to simulate a typical load loss of the heating system, and is stored in the control unit (70).

18. The method according to claim 16, characterized in that, the bypass circuit (50) is closed by: - automatically setting the speed of the circulation pump (30) to a value such that the bypass circuit (50) does not open, - or by means of a manual closure; - or by means of an automatic closure by means of an electromechanical actuator controlled by the control unit (70).

19. The method according to claim 18, wherein the speed of the circulation pump (30) is a speed comprised between 60% and 85% of the maximum speed.

20. The method according to claim 15, characterized in that, with the final step END.hea_1: - the signal of the condition W.20 is emitted, which indicates that the secondary heat exchanger (20) on its primary side is the component responsible for the flow Q.dhw reduction indicated by the alarm signal W.dhw in the previous final step END.dhw_1 of the first partial method M.dhw; - the second partial method M.hea is ended.

21. The method according to claim 15, characterized in that, with the final step END.hea_2: - the signal of the condition W.10-30 is emitted, which indicates that one of the primary heat exchanger (10) and the circulation pump (30) is the component responsible for the flow Q.dhw reduction indicated by the alarm signal W.dhw in the previous final step END.dhw_1 of the first partial method M.dhw; - the second partial method M.hea is ended.

22. The method according to claim 21, characterized in that the condition W.20 and the condition W.10-30 comprise a visual and / or acoustic signal provided to the display of the boiler (1) that can be perceived by the user, and / or a connection service for the user, and / or a communication to a technical assistance service via email.

23. The method according to claim 22, characterized in that, when the circulation pump (30) is intelligent, the condition W.10-30 can incorporate further information requested by the control unit (70) to the circulation pump (30), Said information merging is suitable to identify which between said circulation pump (30) and said primary heat exchanger (10) is the component responsible for said flow Q.dhw reduction indicated by said alarm signal W.dhw in said final step END.dhw_1 of said first partial method M.dhw in said primary circuit (100).

24. The method according to claim 23, characterized in that said control unit (70): - signals a condition W.10, said condition W.10 indicating that said primary heat exchanger (10) is the component responsible for said flow Q.dhw reduction indicated by said alarm signal W.dhw in said final step END.dhw_1 of said first partial method M.dhw in said primary circuit (100); - or signals a condition W.30, said condition W.30 indicating that said circulation pump (30) is the component responsible for said flow Q.dhw reduction indicated by said alarm signal W.dhw in said final step END.dhw_1 of said first partial method M.dhw in said primary circuit (100).

25. The method according to claim 13, characterized in that said method comprises a second partial method M.hea.bis subsequent to said final step END.dhw_1 of said first partial method M.dhw, wherein: - said boiler (1) is in said HEA operating mode; - said circulation pump (30) is set at a speed value such that a bypass circuit (50) is not open; - said control unit (70) contains in memory at least: - a reference flow value Q.hea.bis-rif, said reference flow value Q.hea.bis-rif representing an optimal flow of said boiler (1) in said HEA operating mode; - a threshold value AQ.hea.bis-rif, said threshold value AQ.hea.bis-rif comprising a reduction of the detected flow value with respect to said reference flow value Q.hea.bis-rif, - said reference flow value Q.hea.bis-rif is compared with said value Q.hea.bis of said flow value Q.hea of said boiler (1) in said HEA operating mode flowing in said primary circuit (100), and if: - said difference between said reference flow value Q.hea.bis-rif and said value Q.hea.bis does not exceed said threshold value AQ.hea.bis-rif, said control unit (70) provides a final step END.hea.bis_1, determining that the degraded component of said primary circuit (100) is said secondary heat exchanger (20) on the primary side thereof, - the difference between said reference flow value Q.hea.bis-rif and said value Q.hea.bis exceeds said threshold AQ.hea.bis-rif, the control unit (70) provides a final step END.hea.bis_2, determining that the degraded component of the primary circuit (100) is the primary heat exchanger (10) or the circulation pump (30).

26. The method according to claim 25, wherein the speed of the pump is a speed comprised between 60% and 85% of the maximum speed.

27. The method according to claim 25 or 26, characterized in that, said reference flow value Q.hea.bis-rif is equal to: - the flow value flowing in the primary circuit (100) during the calibration step of the heating system, at the installation time during the first start-up of the boiler (1), or during a subsequent adjustment of the system made by a technician, - or, in the absence of the execution of said calibration step, equal to 0, the value equal to 0 being replaced by an updated value after a first reading of the flow value performed at the end of the first heat request following such installation of the boiler (1), said reference flow value Q.hea.bis-rif being periodically updated and stored in the control unit (70) with subsequent periodic readings, if the reading is greater than the previously stored value.

28. The method according to claim 27, characterized in that, said threshold AQ.hea.bis-rif is pre-established by the builder of the boiler (1) according to laboratory tests and / or periodic monitoring during actual use and / or by a person skilled in the art through other elements.

29. The method according to claim 28, characterized in that, said threshold AQ.hea.bis-rif is not higher than 20% of said reference flow value Q.hea.bis-rif.

30. The method according to claim 15, 20, 21 or 25, characterized in that, in said final step END.hea.bis_1, the control unit (70): - signals the condition W.20, which indicates that the secondary heat exchanger (20) in its primary side is the component responsible for the reduction of the flow Q.dhw indicated by the alarm signal W.dhw in the previous final step END.dhw_1 of the first partial method M.dhw of the primary circuit (100), - ends the second partial method M.hea.bis.

31. The method according to claim 30, characterized in that, in said final step END.hea.bis_2, the control unit (70): - signals the condition W.20, which indicates that the secondary heat exchanger (20) in its primary side is the component responsible for the reduction of the flow Q.dhw indicated by the alarm signal W.dhw in the previous final step END.dhw_1 of the first partial method M.dhw of the primary circuit (100), - ends the second partial method M.hea.bis. - Issue a signal under condition W.10-30, which indicates that one of the primary heat exchanger (10) and the circulating pump (30) is the component responsible for the decrease in flow rate Q.dhw represented by the alarm signal W.dhw in the previous final step END.dhw_1 of the first part of the method M.dhw in the primary loop (100); - End of the second part of the method M.hea.bis.

32. The method according to claim 31, Its features are, When the circulation pump (30) is intelligent, the conditions W.10-30 can incorporate further information requested by the control unit (70) from the circulation pump (30). The information merging is adapted to identify which component in the primary circuit (100) between the circulating pump (30) and the primary heat exchanger (10) is responsible for the decrease in flow rate Q.dhw represented by the alarm signal W.dhw in the previous final step END.dhw_1 of the first part of the method M.dhw.

33. The method according to claim 32, Its features are, The control unit (70): - Issue a signal for condition W.10, which indicates that the primary heat exchanger (10) is the component in the primary loop (100) responsible for the decrease in flow rate Q.dhw represented by the alarm signal W.dhw in the previous final step END.dhw_1 of the first part of the method M.dhw; -Or issue a signal for condition W.30, which indicates that the circulation pump (30) is the component in the primary circuit (100) responsible for the decrease in flow rate Q.dhw represented by the alarm signal W.dhw in the previous final step END.dhw_1 of the first part of the method M.dhw.

34. A boiler (1), comprising: - A primary circuit (100) for heating the heat transfer fluid, the primary circuit (100) further comprising: - Combustion chamber (2), which houses a primary heat exchanger (10) and a burner (3), the burner (3) being supplied with an air / gas mixture by a fan (5) and a gas valve (4), The supply conduit (12) and the first return conduit (11) of the heat transfer fluid flowing in the primary circuit (100) are respectively adapted to guide the fluid to the heating element of the heating system and to guide the fluid from the heating element of the heating system via the circulation pump (30). - Inlet conduit (21) and second return conduit (22) for deflecting the heat transfer fluid in its primary side toward the secondary heat exchanger (20). - A secondary circuit (200) for heating domestic water includes: -The secondary heat exchanger (20); - A supply conduit (23) and a third return conduit (24) are respectively adapted to direct cold water to the inlet on the secondary side of the secondary heat exchanger (20) and to direct hot sanitary water from the secondary side of the secondary heat exchanger (20) to the user. - A three-way baffle valve (40), wherein the three-way baffle valve (40) is adapted to switch the path of the heat transfer fluid as follows: - The boiler (1) is in HEA operating mode to heat the fluid via outlet A to the heating element of the heating system. -Or towards the secondary loop (200), where the heat transfer fluid is directed towards the secondary heat exchanger (20) on its primary side via the inlet conduit (21) and the second return conduit (22), in which case the boiler (1) is in DHW operation mode to heat the domestic water. - Control unit (70). - A sensor device adapted to measure the flow rate Q of the heat transfer fluid flowing in the primary circuit (100), Its features are, The control unit (70) is adapted to exchange and process information with the sensor device, and the control unit (70) is configured to perform the steps of the method according to any one of claims 1 to 14.

35. The boiler (1) according to claim 34, wherein the boiler (1) is a gas-fired condensing boiler.

36. The boiler (1) according to claim 34. Its features are, The control unit (70) is adapted to exchange and process information with the sensor device, and the control unit (70) is configured to perform the steps of the method according to any one of claims 15 to 33.

37. The boiler (1) according to claim 36. characterized in that The sensor device includes: - A flow meter or other equivalent flow sensor located on the primary circuit (100), - and / or smart pumps, - and / or a sensor device that detects one or more physical quantities and calculates the flow rate Q of the heat transfer fluid flowing in the primary loop (100) from the one or more physical quantities.

38. The boiler (1) according to claim 37. characterized in that The boiler (1) includes a bypass circuit (50) adapted to restore the flow rate Q of the heat transfer fluid when the flow rate Q of the heat transfer fluid drops below a certain level.

39. The boiler (1) according to claim 38. characterized in that The boiler (1) includes a calibration bypass adapted to simulate typical load losses of the heating system. The calibration bypass includes a bypass loop (50) adapted to reform the flow rate Q of the heat transfer fluid, as well as a spring check valve (51), a throttle valve (52), and shut-off valves (53, 54).

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