Note: Descriptions are shown in the official language in which they were submitted.
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Hot water appliance
The present invention relates to a hot water appliance.
Conventional systems for central heating (CH) of
buildings comprise a central boiler in which a burner
combusts gas. The heat released during combustion is
transferred to water using a heat exchanger. A pump in the
boiler pumps the heated water through a pipe system in the
building to radiators, which radiators transfer the heat of
the water, mainly through radiation and convection, to the
room in which the radiator is disposed. Via return conduits
the cooled water once again reaches the boiler where the
water is heated.
The boiler is controlled from a thermostat. The
thermostat is arranged in one of the rooms to be heated. The
thermostat comprises a temperature sensor and an operating
member for setting a desired temperature. The thermostat
originally consisted of a bimetal switch or mercury switch
which sent an on/off signal to the boiler. Temperature-
dependent electronic components are used nowadays as
temperature sensor. Modern thermostats further no longer
generate an on/off signal but transmit a modulated signal to
the boiler to enable indication of a variable heat demand.
Modern thermostats are further often provided with a clock
so that the thermostat can also follow a time-dependent
program. For historical reasons these thermostats do however
still communicate with the boiler over a two-wire
connection. Although this is not an insurmountable problem,
it does impose a number of limitations. For reasons of
compatibility the thermostat has to have its own power
supply (generally a battery) and transmitting additional
information, in addition to the heat demand, over the two-
wire connection entails overhead and costs.
US 2010/045470A1 describes a steam distribution system
for heating a building with different dwellings. This system
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is based on remote-controlled steam valves on the radiators
in the dwellings. The operation takes place on the basis of
the temperatures measured in the dwellings and set
temperatures which can optionally be entered via a
thermostat in the dwelling. There is a central control
system which, in addition to controlling the steam valves,
also remotely controls switching on and off of a steam
boiler. This central control communicates wirelessly with
the valves and with the steam boiler via a local network.
DE 102 29 222 Al very generally describes a central
control system which operates all technical installations in
a building on the basis of measurements by sensors in order
to thus minimize the energy consumption. It is not stated
exactly how a hot water appliance present in the system is
controlled.
A central control of technical equipment in a dwelling
or other building is also described in W001/13577 A2. The
control makes use of networks in the building. Few specific
details are described in respect of the heating and hot
water supply. There is however a central thermostat which
communicates with a hot water appliance via the network.
The present invention has for its object to take a
subsequent step in the development of heating boilers which
provides a new range of functionalities.
This object is achieved by providing a hot water
appliance comprising: a heating member for heating water; a
control unit for controlling the heating member, the control
unit comprising a memory for storing a desired temperature
of a space to be heated, and an input/output unit connected
to the control unit; wherein the input/output unit is
adapted to receive a signal representative of a measured
temperature; and wherein the control unit controls the
heating member on the basis of the desired temperature and
the measured temperature. The present invention is based on
the insight that the control unit, i.e. the controller in
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terms of control engineering, does not belong at the
location of the temperature sensor but at the location of
the boiler. This has of course developed historically in
this way because the temperature sensor and the controller
were a single physical component in conventional
thermostats. The introduction of electronic temperature
sensors, such as for instance temperature-dependent
resistors, resulted in thermostats with separate components
on the one hand for detecting the temperature and on the
other for determining the control action. Due to the nature
of a CH-installation, i.e the central generation of heat,
which heat is then distributed over the different locations
in the house where there is a heat demand, there is
something to be said for having the heat demand determined
at the boiler. Compared to a conventional CH-installation
the controller therefore has to be removed from the
thermostat and displaced to the CH boiler. In the first
instance the conventional thermostat is hereby relegated to
being a temperature sensor and operating device. The
"thermostat" determines a deviation on the basis of the '
measured temperature and the set temperature, and transmits
this to the boiler. In the boiler the control unit
determines the control action associated with the deviation
for the purpose of driving the heating member. (In most
cases, the heating member is controlled by controlling the
rotation speed of a fan which draws in the air with which
gas is combusted in a burner.)
However, by going a step further than mere physical
displacement of the controller (the control unit), a greater
range of options is created. This further step is also
determining the deviation in the control unit (in the
boiler)- The conventional thermostat is hereby relegated to
being just a temperature sensor. The advantages hereof are
discussed with reference to embodiments below.
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Although it is not strictly necessary to incorporate
the control unit in the housing of the hot water appliance,
this is recommended.
The space to be heated is not necessarily limited to a
single room. Traditionally present in for instance dwellings
is only a single thermostat, with which the temperature is
measured in a single room and on which only a single desired
temperature can be set. In these cases the CH installation
however heats more than one room. Although the temperature
of the room in which the thermostat is hung is probably the
temperature closest to the set desired temperature most of
the time, the same thermostat is used to "control" the
temperature in the other rooms. Similarly, the term space in
the present invention must not be understood as being
limited to a single room. A space can comprise one or more
rooms. In some cases a space can even comprise only a part
of a room, for instance in the case of a long hallway with
much heat loss, wherein the two ends of the hallway are
heated by their own radiator with their own control circuit.
The measured temperature need not necessarily be the
temperature in a room. In so-called weather-dependent
temperature controls use is made of an outdoor thermometer
and a feed forward controller. The feed forward controller
determines the control action on the basis of the outside
temperature, a (presumed) known effect of the interference
(outside temperature) and a (presumed) known effect of the
control action (the operation of the heating member).
In a further embodiment a hot water appliance is
provided, wherein the input/output unit is adapted to
receive operating instructions from at least one operating
device connected to the input/output unit, and the control
unit is adapted to control the heating member on the basis
of the received operating instructions. The operating
instructions on the basis of which the device is controlled
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by a user can thus be generated remotely of the hot water
appliance.
In a further embodiment of the water appliance
according to the invention the control unit can be adapted
5 to store the received operating instructions in the memory.
A program of temperatures desired over a determined period
can for instance thus be stored.
In order to prevent the hot water appliance switching
off in the unlikely event of the connection between the
input/output unit and the operating device being broken, it
is recommended that a preset desired temperature or a
predefined program for a desired temperature is stored in
the memory and that the control unit is adapted to control
the heating member on the basis of respectively the preset
temperature or the predefined program when no operating
instructions have been respectively received or stored. The
control unit thus has a configurable control algorithm,
whereby the hot water appliance can function independently
on the basis of stored standard settings (default), although
the configuration of the of the control can be modified via
an operating device which communicates with the input/output
unit.
In a specific embodiment the input/output unit
comprises a two-contact inlet/outlet for two-way
communication with an operating device with integrated
temperature sensor. The input/output unit is adapted to send
and receive messages via the two-contact inlet/outlet
according to a protocol suitable for two-way communication
on a two-wire connection and for multiplexing messages from
the operating device and the temperature sensor. In an
alternative, specific embodiment the input/output unit is
adapted such that use is made of two physically separated
one-way connections. In another alternative, specific
embodiment the input/output unit is adapted such that use is
made of two physically separated connections for the
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temperature sensor and the operating device. In another
alternative, specific embodiment the input/output unit is
adapted such that use is made of three physically separated
one-way connections: one for input of messages from the
temperature sensor, one for input of messages from the
operating device and one for output of messages from the
operating device.
In a further embodiment a hot water appliance is
provided, wherein the input/output unit further comprises a
network coupling unit for exchanging data over a network. By
incorporating a network coupling unit in the input/output
unit it is possible to couple components, such as for
instance the temperature sensor or the operating device, to
the control unit over a network connection, for instance a
pre-existing home LAN or office LAN. Such a LAN is
preferably based on TOP, UDP and IP protocols over Ethernet.
In a further embodiment the present invention provides
a hot water appliance, further comprising a web server for
making a user interface available via the network coupling
unit for the purpose of operating the hot water appliance.
In yet another embodiment the invention provides a hot water
device, wherein the user interface made available by the web
server is accessible via the network coupling unit. In yet
another embodiment the invention provides a hot water
appliance, wherein the user interface is adapted to allow
the user to perform at least one of the following actions:
entering a desired temperature; entering a program for a
desired temperature; viewing a measured temperature; viewing
status information relating to the hot water appliance;
viewing maintenance information; viewing error messages;
viewing performance data; and adjusting the hot water
appliance. By means of the incorporated web server it is
possible to navigate to the web server of the hot water
appliance using for instance the browser of a smartphone.
The user is then shown a user interface with which the user
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can operate or program the hot water appliance or view
information. It is thus possible for instance to view the
temperature measured by the connected temperature sensors,
enter or change a desired temperature for a space, enter or
change a program for the temperature variation during the
day or week, set or activate a holiday program, read status
information or maintenance information.
The obvious manner of enabling operation via a network
from a prior art installation would be to provide a
conventional thermostat (with integrated temperature sensor,
operating means and controller) with a network interface and
an incorporated web server.
A further embodiment according to the invention
provides a hot water appliance, wherein the input/output
unit comprises a wireless communication device. In a
specific embodiment the communication device makes use of
one of the WiFi protocols. The communication device can
serve as a WiFi access point. Alternatively, the
communication device is however a WiFi client which connects
to an existing WiFi access point. In this configuration the
hot water appliance forms part of the LAN with which the
WiFi access point is associated, and temperature sensors and
operating devices can be connected via the existing LAN to
the hot water appliance. In other alternative embodiments
use is made of WiFi Ad Hoc or Direct WiFi to connect the
temperature sensors and operating devices.
In yet another embodiment the invention provides a hot
water appliance, wherein the operating device can be
connected via the wireless communication device to the
control unit. The operating device is not limited here to
specialized dedicated operating devices, but mobile phones
with a dedicated application installed, mobile phones which,
as described above, make contact via their web browser with
a web server incorporated into the hot water appliance, and
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personal computers which make contact via a web browser with
the web server can also be envisaged.
The invention further provides a hot water appliance,
wherein: the memory is adapted to store a desired
temperature for two or more spaces to be heated; and the
control unit is adapted to control the heating member on the
basis of the desired temperature in the two or more spaces
to be heated and the measured temperature. In this
embodiment the control unit has two or more target
temperatures (the desired temperatures) and a single
measured temperature and a single measured value. The single
measured value can be the temperature in one of the spaces
for which a desired temperature is stipulated, although it
is also possible for the measured temperature to be a
different temperature, such as for instance an outside
temperature in the case of a weather-dependent temperature
control. There are also two or more target temperatures
here. In the case the hot water appliance has a plurality of
independent hot water circuits and each of the desired
temperatures substantially corresponds to an individual hot
water circuit, it is then relatively easy to control each
hot water circuit separately in order to realize the
different desired temperatures. If this is not the case, the
control unit will have to reach a form of compromise, for
instance by allowing a tolerance at the desired temperature
or by using desired temperature ranges instead of desired
temperatures. Alternatively, a weighting can be used to
indicate a preference between the desired temperatures. If
there are more desired temperatures than measured
temperatures, it is in addition necessary for the control
unit to be able to estimate with a certain degree of
reliability the actual temperature of the spaces for which
the desired temperature is entered but for which no measured
temperature is available.
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In yet another embodiment the invention provides a hot
water appliance, wherein: the input/output unit is adapted
to receive two or more signals which are each representative
of a measured temperature; and the control unit is adapted
to control the heating member on the basis of the desired
temperature in the space to be heated or the desired
temperatures in the two or more spaces to be heated, and the
two or more measured temperatures. In a specific embodiment
the temperature signals are provided to the input/output
unit via a wired connection. In a specific alternative
embodiment the temperature signals are provided wirelessly
to the input/output unit. In yet another specific embodiment
the temperature signals are provided via both wired and
wireless connections.
In a further embodiment a hot water appliance is
provided, wherein: the control unit determines a deviation
between a desired temperature in the space to be heated or
the two or more spaces to be heated and the measured
temperature or temperatures and applies a weighting to the
deviations for the purpose of controlling the heating
member. This is particularly recommended when there are more
spaces with associated desired temperatures than there are
independent hot water circuits. Through the weighting it is
possible to give priority to specific desired temperatures,
since the actually realized temperatures in the spaces with
a corresponding temperature are not independent of each
other.
In yet another embodiment the invention provides a hot
water appliance, further comprising a notification member
for sending a notification via the communication device. The
notification can for instance comprise a error message. The
notification for instance comprises an e-mail message or an
SMS message.
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In an embodiment according to the invention a hot water
appliance is provided, wherein the device comprises a CH
boiler or a combi-boiler.
Further advantages and embodiments are discussed
5 hereinbelow with reference to the accompanying figures, in
which:
. Figure 1 shows a hot water appliance with thermostat
according to the prior art;
Figure 2 shows an alternative hot water appliance with
10 thermostat according to the prior art;
Figure 3 shows a hot water appliance according to the
present invention;
Figure 4 shows a further embodiment of a hot water
appliance according to the present invention;
Figure 5 shows yet another embodiment of a hot water
appliance according to the present invention;
Figure 6 shows an alternative embodiment of a hot water
appliance according to the present invention;
Figure 7 shows a further alternative embodiment of a
hot water appliance according to the present invention;
Figure 8 shows yet another alternative embodiment of a
hot water appliance according to the present invention;
Figure 9 is a schematic representation of the control
unit and the heating member of the hot water appliance of
Figure 8; and
Figure 10 is a flow diagram indicating how the hot
water appliance is controlled.
A hot water appliance 10 (figure 1) according to the
prior art comprises a feed conduit 22 for water. The water
is circulated in the hot water circuit by a pump 24. The
water is pumped through a heat exchanger 26, where it is
heated. The hot water leaves hot water appliance 10 via
water outlet 28. The water in heat exchanger 26 is heated by
a burner 30. Burner 30 comprises an air/gas mixture from a
mixer 32 (for instance a venturi). Air is drawn in by a fan
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34 via an air feed 36 and blown into mixer 32. Gas from a
gas feed 38 reaches mixer 32 via a gas block 39.
Fan 34 and pump 24 are controlled from an external
thermostat 50 located elsewhere. Thermostat 50 is connected
via a cable 42 to hot water appliance 10. Cable 42 is
typically a two-wire connection. Thermostat 50 comprises a
temperature sensor 52 which generates a signal to a
controller 54. Controller 54 is further connected to a
control panel 56. A desired temperature can be entered and
programs set via the control panel. The control panel is
generally provided with a display screen on which the
measured temperature is shown. The display screen usually
also shows information for the purpose of facilitating input
of a desired temperature or a program.
Some prior art hot water appliances 10 are provided
with a dual conduit to enable realization of two hot water
circuits. Hot water circuit 10 of figure 2 shows a first
water feed 22a in which the water is pumped by a first pump
24a, after which the water runs via a first heat exchanger
26a to water discharge 28a. The first hot water circuit is
hereby provided with hot water. The second hot water circuit
feeds water to the second water feed 22b. The water is
pumped by second pump 24b and runs via second heat exchanger
26b to second water discharge 28b. Two separated hot water
circuits are realized in this way. It is otherwise
advantageous to integrate the first and second heat
exchanger 26a, 26b into a single heat exchanger.
In both hot water appliance 10 of figure 1 and hot
water appliance 10 of figure 2 the temperature controller is
located in thermostat 50. The controller determines the
deviation between the temperature measured by temperature
sensor 52 and the desired temperature entered via control
panel 56. On the basis of this deviation an indication is
given via cable 42 that there is a heat demand and, in the
case of a modulated signal, how great the heat demand is.
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Hot water appliance 100 (figure 3) according to the
present invention largely corresponds to the prior art hot
water appliance 10. Water is supplied via a water feed 122
and circulated by means of a pump 124. The water is pumped
via a heat exchanger 126 to water discharge 128. The water
in heat exchanger 126 is heated by a burner 130. The burner
combusts an air/gas mixture. Air is drawn in via an air feed
136 by a fan 134 and blown into mixer 132. Gas moves from
gas feed 138 via gas block 139 to mixer 132, where it mixes
with the air. The controller or control unit 154 which
controls fan 134 and pump 124 is however not now
incorporated in thermostat 50 but in hot water appliance 100
itself. This controller 154 comprises a memory 153 in which
a desired temperature can be stored and an input/output unit
155 (figure 9). A housing 150 is connected via a cable 42 to
the input/output unit 155 of controller 154 in hot water
appliance 100. Housing 150 no longer comprises a controller
54, but only a temperature sensor 152 which provides a
signal representative of the temperature. In addition, a
control panel 156 is arranged in housing 150. Via this
control panel 156 a desired temperature can be entered,
which is transmitted via cable 42 to controller 154 in hot
water appliance 100 and is there stored in memory 153. Other
operating instructions, for instance switch-on and switch-
off times in accordance with a program entered via control
panel 156, can be transmitted via cable 42 to control device
154, which stores them in memory 153. Two signal lines are
drawn in cable 42. These are however not necessarily two
physically separated conductors. Depending on the
embodiment, this can for instance also be a data bus.
In an alternative embodiment (figure 4) there are even
two temperature sensors 152a, 152b connected to control unit
154 in the hot water appliance. The first temperature sensor
152a is received in the same housing 150a as a control panel
156a and connected to hot water appliance 100 via a first
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cable 42a. A second temperature sensor 152b is received in a
second housing 150b and connected to hot water appliance 100
via a second cable 42b. In a specific embodiment the first
housing 150a with the first temperature sensor 152a is
located in a room which is heated and where the temperature
has to be regulated. The first temperature sensor measures
the temperature in the room. The difference from the desired
temperature set via control panel 156a is also the deviation
which has to be removed by control 154. The second housing
150b with the second temperature sensor 152b is placed
outside. The second temperature sensor 152b thus detects the
outside temperature. Controller 154 thus uses the signal
from the first temperature sensor 152a to remove, by means
of a feedback, deviations detected in the inside
temperature, while controller 154 uses the signal from the
second temperature sensor 152b to pro-actively respond to
temperature changes outside by means of a feed forward
coupling. In other embodiments the second temperature sensor
152b is for instance also placed inside, but in a different
room from temperature sensor 152a. It is highly probable in
this case that another control algorithm will also be
necessary.
In another embodiment (figure 5) hot water appliance
100 is adapted to provide two hot water circuits with hot
water. Hot water appliance 10 comprises a first water feed
122a. From the first water feed 122a the water is pumped by
first pump 124a via the first heat exchanger 126a to the
first water discharge 128a. This part forms part of the
first hot water circuit. From a second water feed 122b water
is pumped by a second pump 124b via the second heat
exchanger 126b to the second water discharge 128b. This part
forms part of the second hot water circuit. It is otherwise
advantageous to integrate the first heat exchanger 126a and
the second heat exchanger 126b into a single heat exchanger
with two separated water feeds.
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In this embodiment, as in the previous one, two
temperature sensors 152a and 152b are connected to the hot
water appliance. The first temperature sensor 152a is
received in a first space which is heated using the first
hot water circuit. The second temperature sensor 152b is
received in a second space which is heated using the second
hot water circuit. Controller 154 now also has two separated
control circuits. The first makes use of the temperature
measured by the first temperature sensor 152a and compares
this to a first desired temperature set for the first space.
On the basis of the deviation this control circuit controls
pump 124a of the first hot water circuit (and fan 134). The
second control circuit makes use of the temperature measured
by the second temperature sensor 152b. This is compared to a
second desired temperature set for the second space. The
second pump 124b of the second hot water circuit (and of
course fan 134) is controlled on the basis of the measured
and desired temperature.
In a further embodiment (figure 6) the communication
between the second temperature sensor 152b and hot water
appliance 100 takes a wireless form, for instance via a
Direct WiFi connection. Second housing 150b is provided for
this purpose with a WiFi network transmitter/receiver 158b.
Hot water appliance 100 is also provided with a WiFi network
transmitter/receiver 168. It is hereby not necessary to draw
extra cables.
In yet another embodiment (figure 7) a first housing
150a is provided with a control panel 156a. The control
panel is connected to a WiFi network transmitter/receiver
likewise arranged in first housing 150a. Via this WiFi
network transmitter/receiver the control panel communicates
with a WiFi network transmitter/receiver 168 in hot water
appliance 100. Messages sent from control panel 156a to hot
water appliance 100 mainly comprise information about the
keys which have been pressed. Messages in the opposite
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direction mainly comprise information which is shown on the
screen associated with control panel 156a. In an embodiment
control panel 156a is part of a dedicated operating device
(wireless remote control). In an alternative embodiment
5 housing 150a is the housing of a mobile phone which runs a
dedicated application in order to communicate with hot water
appliance 100 via a Direct WiFi connection.
In another embodiment (figure 8) hot water appliance
100 is provided with a web server 169. The web server has a
10 (wireless or wired) connection to for instance a home
network 210 via a network card. A mobile phone or tablet
computer 150a (with a keyboard and screen 156a) is provided
with a WiFi network chip and communicates wirelessly with
home network 210. The address of web server 169 is visited
15 via an internet browser on mobile phone or tablet 150a. The
web server presents the user of mobile phone or tablet 150a
with a user interface for operating hot water appliance 100.
The user is for instance able to change the desired
temperature, modify a program, view the temperature measured
(by temperature sensor 152b), view the temperature variation
during the day, view status information of hot water
appliance 100 (for instance number of burning hours per day)
and view error messages. If home network 210 allows
connections from the internet it is even possible for a
technician to consult web server 169 via the internet using
his/her personal computer in order to remedy malfunctions or
to for instance perform an online combustion check.
In yet another embodiment (figure 9) the web server on
which the user interface can be found is an external server,
and control unit 154 communicates with this web server via
internet 210. Control unit 154 need then only have an IP
address so that it can be accessed via the internet. The
functions incorporated in hot water appliance 100 are
limited here to the actual control of pump 124 and fan 134.
By providing the user interface on an external web server it
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can be modified in simple manner without operations having
to be performed for this purpose on hot water appliance 100.
The user interface can thus be improved and added to when
new technical options become available. The control unit 154
on hot water appliance 100, which need comprise only the
minimum hardware and software to be able to perform the most
basic functions, even when the connection to the outside
world is lost, can then always be reconfigured when the user
interface is modified.
In this embodiment control unit 154 has two operational
modes; a first mode in which the control is based on
operating instructions entered via the user interface and
transmitted via the internet to input/output unit 155, and a
second mode in which the control takes place on the basis of
a desired temperature stored in memory 153. This can be a
single temperature or a predetermined program of
temperatures at determined times of the day. The first mode
is the normal operational mode, while the second mode is an
exception mode. This latter mode serves only to guarantee
continued operation of hot water appliance 100 in the
unlikely event operating device 154 were not to receive any
operating instructions, for instance due to failure of the
network to which input/output unit 155 is connected. In both
modes an actually measured temperature originating from
temperature sensor 152 applies as reference. In order to
enable realization of both operational modes, the actual
control part 157 of control unit 154 comprises two operating
programs, which are shown schematically here; an extensive
regular operating program 162 which acts on the basis of the
operating instructions coming in via input/output unit 155
and a much more limited emergency program 161 which acts on
the basis of the information stored in memory 153.
Figure 10 shows schematically how control unit 154
switches between the two operational modes. After a control
cycle has been started in block 201, a check is made in
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block 202 as to whether input/output unit 155 is receiving
signals which may comprise operating instructions.
When this is the case, these instructions are read in
block 203 and, among other information, a desired
temperature value Tgew is derived therefrom_ The measured
temperature T is subsequently read in block 205. This
measured temperature is then compared in block 206 to the
desired temperature Tgew. If it follows from this comparison
that the desired temperature has been reached, the control
unit need not undertake any further control action and the
program returns to checking for the presence of input
signals in block 202. If on the other hand it follows from
the temperature comparison in block 206 that a control
action is required, control signals for pump 124 and fan 134
are generated in block 207. The program then returns to
block 202.
When it is determined in block 202 that input/output
unit 155 is not receiving (or has not received) any
operating instructions, a switch is made to the emergency
program. The desired value of the temperature Tgew, which is
stored in memory 153, is in that case read in block 204. The
program then continues reading the measured temperature in
block 205. All further program steps are identical to the
steps taken when an input signal is detected.
Optimal use can in this way be made of the
possibilities of the internet or other external sources in
order to make available a highly user-friendly operation
with extensive options without extensive provision having to
be made for this purpose in the hot water appliance.
Furthermore, the operational reliability of the hot water
appliance is in this way always guaranteed, even when
communication means fail.
The described embodiments and the embodiments shown in
the figures are only exemplary embodiments by way of
illustration of the invention. The invention is not limited
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to these embodiments. It will be apparent to the skilled
person that many variations of and modifications to the
shown embodiments are possible within the invention. Instead
of storing a desired temperature in the memory of the
control unit another control parameter could also be stored,
for instance a table with switch on/off times. The
input/output unit would then have to receive a time signal
instead of a temperature signal. It is thus also possible
without problem to combine features of different embodiments
to form new embodiments without departing from the
invention. The shown embodiments are therefore not
limitative for the scope of protection sought. The scope of
protection is defined solely by the following claims.
