Diagnostic method for diagnosing the correct operation of a heating and/or cooling system

Abstract

A diagnosis method for the diagnosis of the correct function of a heating and/or cooling system with at least one load circuit (6), through which a fluid flows as a heat transfer medium. For the diagnosis an opening degree (V.sub.pos,n) of the load circuit (6) is changed for changing the flow. Subsequently a differential pressure (H.sub.pu) across the load circuit (6) and/or a volume flow of a fluid flowing through the load circuit (6) is detected and the detected values, or at least a value derived from the detected values, are/is compared to at least one predefined system limit value.

Claims

1. A diagnosis method for a diagnosis of a correct function of a heating and/or cooling system with at least one load circuit, through which a fluid flows as a heat transfer medium, the method comprising the steps of: changing, for the diagnosis, an opening degree of the at least one load circuit for changing the flow; subsequently detecting a differential pressure across the load circuit or a volume flow of a fluid flowing through the load circuit or both a differential pressure across the load circuit and a volume flow of a fluid flowing through the load circuit to provide detected values; comparing the detected values or comparing a value derived from the detected values to at least one predefined system limit value; determining whether the heating and/or cooling system is functioning properly based on the comparison of the detected values or the value derived from the detected values to the at least one predefined system limit value, wherein: several load circuits are present and the opening degree in each case of one of the load circuits is changed in a successive manner for diagnosis; simultaneously, the opening degree of further remaining load circuits remains unchanged and subsequently the differential pressure or the volume flow or both the differential pressure and the volume flow of the fluid flowing through the load circuit with an increased opening degree are detected and the detected values or a value derived from the detected values are compared to at least one predefined system limit value; an error notice is issued if a deviation from the at least one predefined system limit value is measured; the error notice indicates to a user or operator of a malfunction of the heating and/or cooling system necessitating an inspection of the heating and/or cooling system.

2. The diagnosis method according to claim 1, wherein the opening degree of the load circuit is changed in a manner such that the opening degree is increased for increasing the flow.

3. The diagnosis method according to claim 1, wherein the opening degree of the at least one load circuit is changed in a manner such that the opening degree of the at least one load circuit is reduced for reducing the flow.

4. The diagnosis method according to claim 1, wherein the differential pressure or the volume flow or both the differential pressure and the volume flow are detected by a circulation pump assembly, which delivers the fluid through the load circuit.

5. The diagnosis method according to claim 1, wherein a hydraulic resistance for an opened load circuit is determined as a derived value from the detected differential pressure or the volume flow or both the differential pressure and the volume flow.

6. The diagnosis method according to claim 5, wherein the hydraulic resistance is compared to at least one predefined system limit value for the hydraulic resistance.

7. The diagnosis method according to claim 6, wherein the hydraulic resistance is compared to a minimal or a maximal or both a minimal and a maximal system limit value.

8. The diagnosis method according to claim 1, wherein the error notice is produced on exceeding a maximal system limit value or falling short of a minimal system limit value or both exceeding a maximal system limit value and falling short of a minimal system limit value.

9. A manifold device for a heating and/or cooling system with at least one load circuit, wherein the manifold device comprises: at least one circulation pump assembly for delivering a fluid through at least one load circuit; a regulating valve for setting the volume flow through the load circuit, wherein one of the at least one circulation pump assembly and at least one sensor is configured to detect a volume flow through the at least one load circuit or a differential pressure across the load circuit or both the volume flow and the differential pressure; a control device which is connected to the regulating valve for actuation thereof and is connected to the detecting device, wherein the control device is configured to: change, for a diagnosis, an opening degree of the load circuit for changing the flow; subsequently detect, with the detecting device, a differential pressure across the load circuit or a volume flow of a fluid flowing through the load circuit or both the differential pressure across the load circuit and a volume flow of a fluid flowing through the load circuit to provide detected values; compare the detected values or compare a value derived from the detected values to at least one predefined system limit value; determining whether the heating and/or cooling system is functioning properly based on the comparison of the detected values or the value derived from the detected values to the at least one predefined system limit value, wherein: several load circuits are present and the opening degree in each case of one of the load circuits is changed in a successive manner for diagnosis via the control device; simultaneously, the opening degree of further remaining load circuits remains unchanged and subsequently the differential pressure or the volume flow or both the differential pressure and the volume flow of the fluid flowing through the load circuit with an increased opening degree are detected and the detected values or a value derived from the detected values are compared to at least one predefined system limit value; an error notice is issued if a deviation from the at least one predefined system limit value is measured; the error notice alerts a user or operator to inspect the heating and/or cooling system based on a malfunctioning of the heating and/or cooling system.

10. The manifold device according to claim 9, wherein regulating valves are provided in each case for setting a volume flow in one of the several load circuits, wherein the control device is configured to activate the regulating valves and is signal-connected to the regulating valves for activation thereof.

11. The manifold device according to claim 10, wherein the circulation pump assembly is situated in a common feed conduit to all load circuits.

12. The manifold device according to claim 9, wherein the circulation pump assembly functions as a detecting device and is configured to determine a differential pressure across the circulation pump assembly or a volume flow through the circulation pump assembly or both a differential pressure and a volume flow, and is signal-connected to the control device for transferring determined values.

13. The manifold device according to claim 10, wherein the circulation pump assembly functions as a detecting device and is configured to determine a differential pressure across the circulation pump assembly or a volume flow through the circulation pump assembly or both a differential pressure and a volume flow, and is signal-connected to the control device for transferring determined values.

14. The manifold device according to claim 9, wherein the control device is further configured to produce an error message upon exceeding a maximal system limit value or falling short of a minimal system limit value or both exceeding a maximal system limit value and falling short of a minimal system limit value.

15. A diagnosis method comprising: providing at least one of a heating and cooling system comprising a load circuit, wherein fluid flows through the load circuit as a heat transfer medium; changing an opening degree of the load circuit for changing a flow of the fluid through the load circuit; detecting a differential pressure across the load circuit or a volume flow of a fluid flowing through the load circuit after changing the opening degree of the load circuit or detecting both a differential pressure across the load circuit and a volume flow of a fluid flowing through the load circuit to provide detected values after changing the opening degree of the load circuit; comparing the detected values with at least one predefined system limit value or comparing a value derived from the detected values to the at least one predefined system limit value to provide at one or more compared values; determining whether the heating and/or cooling system is functioning properly based on the one or more compared values.

16. The diagnosis method according to claim 15, wherein the opening degree of the load circuit is changed in a manner such that the opening degree is increased for increasing the flow, wherein an error notice is issued if a deviation from the at least one predefined system limit value is measured, the error notice alerting a user or operator to inspect the at least one of the heating and cooling system based on a malfunctioning of the at least one of the heating and cooling system.

17. The diagnosis method according to claim 15, wherein the opening degree of the load circuit is changed in a manner such that the opening degree of the load circuit is reduced for reducing the flow.

18. The diagnosis method according to claim 15, wherein the differential pressure or the volume flow or both the differential pressure and the volume flow are detected by a circulation pump assembly, which delivers the fluid through the load circuit.

19. The diagnosis method according to claim 15, wherein a hydraulic resistance for the opened load circuit is determined as a derived value from the detected differential pressure or the volume flow or both the differential pressure and the volume flow, wherein an error notice is issued when the heating and/or cooling system is in an improper functioning state.

20. The diagnosis method according to claim 19, wherein the hydraulic resistance is compared to at least one predefined system limit value for the hydraulic resistance.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings:

(2) FIG. 1 is a schematic view showing a heating or cooling system, in which the regulating method according to the invention as well as the manifold device according to the invention are applied;

(3) FIG. 2 is a schematic perspective view showing a manifold device according to the invention;

(4) FIG. 3 is a plan view of the manifold device according to FIG. 2;

(5) FIG. 4 is a graph showing the switch-on durations of a load circuit; and

(6) FIG. 5 is a schematic view showing the cooperation of individual parts of a regulating method according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(7) FIG. 1 shows a heating or cooling system which can be designed for example as a floor heating system. Hereinafter, the invention is described with the example of a heating system. However, it is to be understood that the invention could also be correspondingly realized as a cooling system. Alternatively, the system can also be applied as a heating as well as for cooling, i.e. for example in winter as a heater and as a cooling system in summer.

(8) The heating system shown in FIG. 1 comprises an inlet 2 and an outlet 4 which are provided for connection to a supply, i.e. for example to a boiler, to a heat reservoir or to a cooling installation etc. Moreover, several load circuits 6 are provided, which for example represent individual floor heating circuits which in each case heat a part region such as a room of a building. A circulation pump or a circulation pump assembly 8 is arranged at the entry side, i.e. upstream of the load circuits 6. This pump or pump assembly comprises a speed-regulated drive motor and is connected to a control device 10 for the activation and in particular for setting the speed. The entry side of the circulation pump assembly 8 is connected to the inlet 2.

(9) Moreover, a mixing device is arranged upstream of the circulation pump assembly 8. The mixing device comprises a mixing conduit 12 which connects a return 14 from the load circuits 6 to a mixing point 16 in the flow path from the inlet 2 to the circulation pump 8. I.e. fluid from the inlet 2 is mixed with fluid from the return 14, at the mixing point 16, in order to be able to set the feed temperature. A regulating valve which forms a mixing valve 18 is arranged in the return 14, downstream of the branching 17 of the mixing conduit 12 in the return 14, for the regulation of the mixing ratio. This is likewise signal-connected to the control device 10 for its activation. Moreover, a check valve 20 is arranged in the mixing conduit 12 and prevents the backflow of fluid from the mixing point 16 into the return 14. The volume flow which flows out of the return 14 to the outlet 4 changes in a manner depending on the opening degree of the mixing valve 18. If the volume flow is reduced by way of a reduction of the opening degree of the mixing valve 18, a greater share of the fluid flows through the mixing conduit 12 to the mixing point 16. If the opening degree of the mixing valve 18 increases, the volume flow through the outlet 4 increases and accordingly a smaller share of the fluid flow flows from the return 14 through the mixing conduit 12 to the mixing point 16. Thus, the share of fluid from the return 14 and which is admixed at the mixing point 16 to the fluid out of the inlet 2 changes. The feed temperature of the fluid from the inlet 2 can be lowered by way of the mixing of the fluid from the return 14 and which is colder in the case of a heating system, with the warmer fluid from the inlet 2. In the case of a cooling system, vice versa warmer fluid from the return 14 is admixed to the colder fluid from the inlet 2, in order to increase the feed temperature. The circulation pump 8 delivers the fluid from the mixing point 16 to the load circuits 6 arranged in parallel.

(10) In each case, a regulating valve 24 is arranged at the exits 22 of the load circuits, i.e. in their returns, and this valve is designed as an electromotorically driven regulating valve 24 and is activated by the control device 10. The regulating valves 24 can be varied in their opening degree and also be completely closed, in order to set the flow or volume flow through each individual load circuit 6. Thereby, the regulating valves 24 can be individually activated by the control device 10, so that an adaptation of the flow through each individual load circuit 6 is possible independently of the remaining load circuits.

(11) Moreover, temperature sensors are provided in the shown system. A first temperature sensor is a feed temperature sensor 26 and detects the feed temperature of the fluid which is fed to the load circuits 6. Moreover, temperature sensors 28 are arranged at the exits 22 of the load circuits 6 and detect the exit temperatures of the fluid from the individual load circuits 6. The temperature values which are detected by the feed temperature sensor 26 and the temperature sensors 28 are led via suitable communication connections likewise to the control device 10.

(12) The circulation pump assembly 8 is moreover designed to determine a differential pressure H.sub.pu between the entry side and the exit side of the circulation pump assembly 8 and which simultaneously corresponds to the differential pressure between the entries 30 and the mixing point 16, i.e. which corresponds to the pressure drop via each branches between these points which are defined by the load circuit 6. Moreover, the circulation pump assembly 8 is designed to determine the flow through the circulation pump assembly 8. These values detected by the circulation pump assembly 8 are likewise led via a signal connection to the central control device 10. Alternatively, suitable pressure sensors and flow sensors could be arranged additionally to the circulation pump assembly 8, in order to determine the pressure difference between the entry and exit of the load circuits 6 as well as the flow through all load circuits 6.

(13) On basis of the differential pressure H.sub.pu, i.e. the pressure drop via the load circuit can be used in regard to the characteristic of the valves lying in the flow path, particularly of the check valve 20 and the regulating valve 24, moreover, the volume flow through each load circuit 6 depending on the opening degree of the per-respective valve 24 can be determined. Since the controller 10 controls the opening degree of the regulating valves 24, the control device 10 can determine the flow rate or volume flow rate through the associated load circuit 6 from the said values.

(14) Thus, as described below, a desired flow rate can be adjusted by the load circuit 6.

(15) The control device 10 is moreover provided with a communication interface 32 which is designed to communicate with one or more room thermostats 34 or room temperature probes 34. Such a room thermostat 34 is preferably provided in each room which is to be thermally regulated by a load circuit 6. In the shown example, the communication interface 32 is designed as a radio interface which communicates with corresponding radio interface 36 of the room thermostat 34. Alternatively, a lead connection via a separate signal lead, a bus system or a powerline communication could be provided. The room thermostats 34 detect the room temperatures in the rooms to be thermally regulated. Moreover, a desired temperature for the room to be thermally regulated can be set by the user in each case in the known manner via the room thermostats 34.

(16) The control device 10 is designed for the use of different regulating methods. Thus according to a first regulating method, the control device 10 effects a volume flow regulation for the individual load circuits 6. For this, the temperature difference ΔT between the entry 30 and the exit 22 of each load circuit 6 is detected. This is effected via the feed temperature sensor 26 as well as the temperature sensor 28 belonging to the respective load circuit 6. The volume flow is regulated or set by the control device 10 by changing the opening degree V.sub.pos,n of the regulating valve 24 in dependence on this temperature difference ΔT, via the regulating valve 24 of this load circuit 6, so that the temperature difference ΔT corresponds to a predefined setpoint which is stored in the control device 10, i.e. that ΔT is kept constant. This is effected independently for each load circuit 6, so that all load circuits can be adapted by the volume flow regulation to the actual energy requirement. The setpoint can be the same for all load circuits 6 or different setpoints can be defined for individual load circuits. The setpoints are stored in the control device 10.

(17) Thereby, the circulation pump assembly 8 is regulated by the control device 10 such that it maintains a predefined pressure difference setpoint between the entry and exit of the circulation pump assembly. This differential pressure is thus regulated to a pressure difference setpoint which is likewise set or defined by the control device 10. The pressure difference setpoint H.sub.ref is set by the control device 10 in dependence on the opening degree of the regulating valves 24. For this, all opening degrees of all regulating valves 24 are considered by the control device 10. That regulating valve which is presently open the furthest, i.e. has the greatest opening degree, then forms the basis of the setting of the pressure difference setpoint by the control device 10. Thus, the opening degree of the regulating valve which is open the furthest, is compared to a desired opening degree V.sub.pos,ref. If the present or current opening degree V.sub.pos,n of the regulating valve 24 with the greatest opening degree exceeds the desired opening degree V.sub.pos,ref, then the pressure difference setpoint H.sub.ref is increased. If the desired opening degree V.sub.pos,ref is fallen short of by the actual opening degree V.sub.pos,n, then the pressure difference setpoint H.sub.ref is accordingly lowered. The increase or lowering is preferably effected proportionally to the deviation from the desired opening degree V.sub.pos,ref.

(18) A further control loop or a further regulating method which is carried out by the control device 10 relates to the regulation of the feed temperature T.sub.mix at the entry 30 of the load circuits 6 and which is detected by the feed temperature sensor 26. The feed temperature T.sub.mix can be changed or set by the control device 10 by way of activation of the mixing valve 18. For this, the control device 10 forms a feed temperature setting device which sets the feed temperature T.sub.mix, i.e. its setpoint in dependence on the switch-on duration, i.e. the relative switch-on duration D of the load circuits 6. The significance of the relative switch-on duration D is described in more detail by way of FIG. 4. FIG. 4 for a load circuit 4 shows how this is switched on and off in an alternating manner. “1” thereby means switched-on and “0” means switched-off. The load circuit is switched on for the time duration t.sub.on, and the load circuit is switched off for the time duration t.sub.off. The cycle time t.sub.z thereby corresponds to the sum of the switch-on time and switch-off time, i.e. t.sub.z=t.sub.on+t.sub.off. The relative switch-on duration D is the ratio of the switch-on time t.sub.on to the cycle time t.sub.z, as is represented in FIG. 5. The cycle time or cycle duration t.sub.z is thus the time interval between the switching-on of the load circuit 6 and the subsequent next switching-on of the load circuit 6. The switching-on and switching-off of the load circuit results from the signals of the associated room thermostats 34. If in the case of a heating system, the room thermostat 34 notes that a set desired temperature is fallen short off, the control device 10 switches on the load circuit 6 associated with the room, by way of opening the associated regulating valve 24. The volume flow regulation described above for the respective load circuit 6 is then effected. If the room thermostat 34 notes that the set temperature setpoint is reached, the control device 10 switches off the load circuit 6 belonging to the room, by way of completer closure of the regulating valve 24.

(19) The feed temperature T.sub.mix and its setpoint is the same for all load circuits 6 and is set by the control device 10 in dependence on that load circuit 6 which has the longest relative switch-on duration D, i.e. the relatively largest load cycle. This is the load circuit 6 with the greatest thermal or cooling requirement, so that it is useful to adequately set the feed temperature T.sub.mix for this load circuit 6. The remaining load circuits 6 which have lower relative switch-on durations D accordingly have a lower energy requirement, so that the set feed temperature T.sub.mix for these load circuits is likewise sufficient. The setting of the feed temperature T.sub.mix is effected in a manner such that the relative switch-on duration D is compared to a limit value or a desired switch-on duration D.sub.ref. If the relative switch-on duration D exceeds the desired switch-on duration D.sub.ref, the feed temperature T.sub.mix respectively at first its setpoint is increased in the case of a heating, and the feed temperature T.sub.mix respectively its setpoint is reduced in the case of a cooling system. Vice versa, for the case that the relative switch-on duration D falls short of the desired switch-on duration D.sub.ref, the feed temperature T.sub.mix respectively its setpoint is reduced in the case of a heating, and increased in the case of a cooling system. This is preferably effected proportionally to the deviation of the switch-on duration D from the desired switch-on duration D.sub.ref. Alternatively, a change can also be effected in fixed steps. The desired switch-on duration D.sub.ref is stored as a preset value in the control device 10.

(20) It is shown in FIG. 5 as to how the individual regulating methods or control loops cooperate. All the previously described control loops or regulating methods are preferably carried out continuously and simultaneously. The first control loops R.sub.1 which are shown in FIG. 5 relate to the volume flow regulation for the individual load circuits 6. Thereby, a regulation for each load circuit 6 is effected independently, i.e. for each load circuit 6 the differential temperature ΔT.sub.n (ΔT.sub.n=T.sub.mix−T.sub.ret,n, wherein T.sub.ret,n is the exit temperature of the respective load circuit which is detected by the associated temperature sensor 28) is compared to the temperature difference setpoint ΔT.sub.ref. The counter n in FIG. 5 indicates the respective load circuit 6. The temperature difference setpoint ΔT can also be differently defined for individually load circuits 6 and be stored in the control device 10. Alternatively, it is also possible to apply the same temperature different value ΔT.sub.ref for all load circuits. However, it is always the actual exit temperature T.sub.ref,n of the respective load circuit which forms the basis of for the regulation, i.e. the exit temperature T.sub.ref1 for the first load circuit 6, the exit temperature T.sub.ref2 for the second load circuit, etc. The opening degree V.sub.pos,n for the associated regulating valve 24 is set by the control device 10 in dependence on the comparison of the differential temperature ΔT.sub.n with the temperature difference setpoint ΔT.sub.ref.

(21) A second control loop R.sub.2 which is represented in FIG. 5, relates to the previously described setting of the feed temperature T.sub.mix by way of the control of the mixing valve 18. For this, a control variable V.sub.pos,mix which corresponds to the opening degree of the mixing valve 18, is set by the control device 10 by way of the relative switch-on duration D being compared to the desired switch-on duration D.sub.ref in the manner described above.

(22) A third control loop R.sub.3 and a fourth control loop R.sub.4 which are shown in FIG. 5 and are implemented in the control device 10, relate to the differential pressure regulation in the circulation pump assembly 8. Thus, the differential pressure H.sub.pu between the entry and exit of the circulation pump assembly 8, i.e. between the entry and exit of the load circuits 6 is regulated to a pressure difference setpoint H.sub.ref, which is effected in the control loop R.sub.4. Moreover the pressure difference setpoint H.sub.ref for its part is regulated and set in the control loop R.sub.3, which is effected in the manner described above in dependence on the opening degree V.sub.pos,n of the regulating valve 24. For this, the regulating valve 24 is with the greatest opening degree V.sub.pos is considered and is compared to a desired opening degree V.sub.pos,ref. If the desired opening degree V.sub.pos,ref is fallen short of, then the pressure difference setpoint H.sub.ref is increased proportionally. If the desired opening degree V.sub.pos,ref is exceeded, accordingly the pressure difference setpoint H.sub.ref is reduced. As is likewise represented in FIG. 5, the circulation pump assembly 8 comprises a detection device 38 which estimates or determines the actual pressure difference H.sub.pu from the speed S.sub.pu and the electrical power P.sub.pu.

(23) The four shown control lops R.sub.1, R.sub.2, R.sub.3, R.sub.4 are differently quick and differently sluggish, so that they preferably do not interact with one another, i.e. they do not mutually influence one another. The quickest control loop is the control loop R.sub.4 which regulates the pressure difference H.sub.pu across the circulation pump assembly 8 to the pressure difference setpoint H.sub.ref. The next slower control loop is the control loop R.sub.1 which regulates the volume flow through the individual load circuits 6. Even slower is the control loop R.sub.3 which regulates the pressure difference setpoint H.sub.ref. This control loop is so slow that this regulation preferably does not influence the control loop R.sub.1. In FIG. 5 not shown are two further control loops, namely the control loop for regulating the room temperature by switching-on and switching-off the load circuit 6 as well as the control loop which regulates the feed temperature on the elected feed temperature setpoint. These two control loops are preferably designed still slower than the preceding described load circuits whereas that load circuit which sets the feed temperature is preferably the slowest load circuit.

(24) Apart from the regulation method described above, the control device 10 can also assume further functions. It is possible to store certain priorities for the individual load circuits 6 in the control device 10, since this control device communicates with room thermostats 34 and switches on the load circuits 6 by way of opening the regulating valves 24, in dependence on the signals from the room thermostats 34. Thus, with a heating system and when very cold, it is possible for example to not simultaneously activate all load circuits 6 in the case that the heat quantity made available by the boiler would not be sufficient. For heating, firstly prioritized heating circuits such as for example living rooms or bath can be switched on, and less important load circuits 6, for example for heating bedrooms can firstly remain switched off. Thereby, the control device 10 can automatically detect that the heating power available is not sufficient, specifically when all regulating valves 34 are opened, i.e. have the maximal opening degree and despite this the temperature difference ΔT between the entry 30 and the exit 22 becomes too large. This functions in a corresponding manner also with a cooling system, but in reverse. The priority of the load circuits 6 can be preset and be stored in the control device 10. Moreover, the control device 10 can also be designed such that for heating rooms, it increases the feed temperature T.sub.mix for a certain time above the usually sought setpoint resulting from the previously described regulation, in order to permit a rapid heating of the rooms.

(25) Finally, the control device 10 can also have a diagnosis function or diagnosis module which diagnoses the correct function of the regulating valves 24 as well as of the load circuits 6. Thus, the control device 10 in a diagnosis mode can individually open the regulating valves 24 of the load circuits 6 or increase or reduce the opening degree of the regulating valves 24, ideally to the maximum. Thereby, in each case only one regulating valve 24 is opened and closed further departing from an initial opening degree, whilst the other regulating valves 24 remain unchanged or closed. Preferably the regulating valve 24 of the load circuit 6 which has to be rechecked is further opened. Subsequently, the flow through the circulation pump assembly 8 as well as the differential pressure across the circulation pump assembly 8 is detected and the hydraulic resistance of the system respectively a change of the hydraulic resistance is determined from this. The control device 10 also receives information or signals from the circulation pump assembly 8 which specifies the flow and the differential pressure. The control device 10 compares the determined hydraulic resistance with a maximum hydraulic resistance with is predefined for the system and which is stored in the control device 10. If the detected hydraulic resistance exceeds the predefined maximum hydraulic resistance, this indicates an error and the control device 10 signalizes this error, so that the system can be subsequently examined. If the hydraulic resistance before and after the opening of the regulating valve 24 are compared to one another, then the correction function of the regulating valve 24 can be determined from this. Moreover, the hydraulic resistance can also be compared to a minimal value in the control device 10. If a stored minimal value is fallen short of, then likewise a malfunction can be deduced from this.

(26) The diagnostic function described above can be also realized so that the pressure loss and hence, the hydraulic resistance is taken into account only the individual load circuits 6 or determined by the control device 10. This can also be done by knowing the characteristics of the valves lying in the flow path, especially the check valve 20 and the regulating valve 24 taking into account the known opening degree of the valves 24. If the pressure losses of the valves are known in the given operating state, then the proportion of the total pressure loss of the circulation pump 8 which is provided between input and output can be determined, which is caused by the respective load circuit 6 itself. Accordingly, the permissible limits for the pressure loss and the hydraulic resistance of the load circuit 6 itself can be parked. I.e., it will only take into account the hydraulic resistance of the load circuit in the comparison with the permissible limits, the limits are limits for the hydraulic resistance of the load circuit.

(27) The essential components of the heating system shown in FIG. 1 are preferably integrated into a manifold device in the form of a heating manifold, as is shown in FIGS. 2 and 3. Thereby, all essential components lying within the dashed line in FIG. 1 are integrated into the manifold device in the form of a construction unit. Thus, the heating manifold 40 which is shown in FIGS. 2 and 3 as a central component comprises the circulation pump assembly 8. This comprises a pump housing 42, in which a rotatable impeller is arranged. The impeller is driven by an electric drive motor which is arranged in a motor housing or stator housing 44. A terminal box or electronics housing 46, in which the control device 10 is accommodated, is arranged on the axial end of the stator housing 44 which is away from the pump housing 42. The pump housing 42 compromises the inlet 2 as well as the outlet 4 in the form of connections of external pipe conduits. Moreover, the mixing valve 18 is arranged in the pump housing, and the mixing conduit 12 with the mixing point 16 is formed in the pump housing. The pump housing 42 is connected at one side to the actual manifold 48. The manifold 48 comprises modules 50 for the individual load circuits, in this case six load circuits 6. The regulating valves 24 as well as connections which form the entries 30 for the load circuits 6 are arranged in the modules 50. Moreover, each module 50 comprises a connection which forms the exit 22 for the respective load circuit 6. Pipe conduits which form the load circuits 6, for example pipe conduits of a floor heating are be connected to the connections forming the entries 30 and the exits 22. A feed conduit and a return conduit which are connected to the pump housing 42 are arranged in the manifold 48, wherein the return conduit is connected to the return 14 in the pump housing and the feed conduit is connected to the exit side of the circulation pump 8. The temperature sensors 26 and 28 are also integrated into the manifold 48 or the pump housing 42. Thus, preferably, only the room thermostats 34 with their radio interfaces 36 form external components of the regulation technology, which however can be easily connected by way of the radio connection to the communication interface 32 of the control device 10 which is arranged in the electronics housing 46. All other necessary electric and/or electronic components for the control and/or regulation are integrated into the heating manifold 40 as a premanufactured construction unit.

(28) While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.