GB2094503A

GB2094503A - Control units

Info

Publication number: GB2094503A
Application number: GB8100958A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-01-13
Filing date: 1981-01-13
Publication date: 1982-09-15

Abstract

A housed control unit for a central heating system has a digital display device (4), a temperature sensor and an audible signalling device both located behind a grille (6), a power input, a control signal output (e.g. to relays operating a boiler fuel solenoid valve and a water circulating pump, electronic control circuitry including memory and timing circuits, and manual controls such as touch- switches (9). Time- and temperature-dependent control signals are produced at the control output depending on the pre- setting of the unit with the manual controls (9). The display device (4) can display time and temperature and the audible signalling device can give an audible indication of operation of the unit (e.g. when a pre-set temperature is reached). The unit can be wall-mounted in a sinking box remote from a central heating boiler and connected thereto via leads at low voltage. The leads provide a low voltage supply to the unit, and the necessary outputs to the fuel valve and water pump relays. The unit may be coupled to other controls and sensors so as to act e.g. as a door-bell and smoke detector. The circuitry preferably comprises a microprocessor. A knob (5) is coupled to a potentiometer for setting the pump ON/OFF temperature. <IMAGE>

Description

SPECIFICATION Control units This invention relates to control units for central heating systems.

With conventional domestic hot water central heating systems it is usual to provide a controller mounted in the vicinity of the central heating boiler, such controller incorporating a clock and electrical switches which operate to switch the boiler on and off in accordance with a manually pre-set time cycle. Usually also there is a wallmounted manually adjustable thermostat at a location remote from the boiler which acts to control a water circulation pump during operational periods of the heating system.

With this known arrangement the requisite electrical installation work may be complicated and/or inconvenient having regard to the multiple connections which have to be made between the various electrical components including the thermostat, the controller and electricallyoperated control mechanisms of the heating system such as a fuel supply solenoid valve of the boiler and the water circulation pump especially bearing in mind that it is usual for all such components to operate at mains voltage thereby requiring the use of mains leads to interconnect the components.Moreover, the known arrangement may not be suited to ready and convenient presentation of information pertaining to operation of the heating system, such as information concerning the pre-set timing cycle and the pre-set room temperature, in so far as it may be necessary to consult separate mutually remote devices possibly at inconveniently accessible locations in order to obtain such information. Further, the versatility of the known arrangement may be limited in that the accommodation of supplementary control functions may render manufacture and/or installation of the electrical components unduly complicated or inconvenient.

An object of the present invention is to provide a versatile control unit for a central heating system which is simple and convenient to manufacture and install and which can readily and conveniently make available a range of information pertaining to the operation of the heating system.

According to the invention therefore there is provided a housed control unit for a central heating system having a digital display device, a temperature sensor, an audible signalling device, a power input, a control signal output, electronic control circuitry including memory and timing circuits connected to said devices, sensor, input and output, and manually operable controls for controlling operation of said circuitry, said circuitry being operable to feed switching control signals to said control signal output in dependence on operation of said manually operable controls and in dependence on the temperature as determined with said temperature sensor and the time as determined with said timing circuit, and said circuitry also being operable to effect production of a visual display on said digital display representative of time and/or temperature and to effect production of an audible signal with said audible signalling device in correspondence with operation of the unit.

With this arrangement, it can be possible, by appropriate operation of the said controls, readily and conveniently to enter data into the said memory circuit corresponding for example to a desired time cycle for switching a central heating boiler on and off and also a desired room temperature at which a water circulation pump of the heating system is to be switched on and off, said stored data being utilised in the production of said control signals and said control signals being utilisable to effect said switching operation. Thus, the housed control unit of the present invention can provide all requisite control of functions for a central heating system thereby enabling electrical installation work for such system to be effected in a particularly simple and convenient manner.

Most preferably, and to further facilitate installation, the control unit operates at a low supply voltage fed to said power input for example from a power supply unit located in the vicinity of the boiler, such unit having a stepdown mains transformer. Preferably also one or more relays of any suitable kind including semiconductor are provided in the vicinity of the boiler to effect switching of heating system components in response to actuation by said control signals. Conveniently the power supply unit and the relays may be provided in a common housing.

The control unit of the invention can be mounted without difficulty at a convenient location which may be remote from the central heating boiler. Thus the unit can be readily accessible for purposes of operation of the controls thereof and also for purposes of inspection of the time and/or temperature information presentable on the digital display device. The unit may be arranged to provide a contrinuous or on-demand display of current time.

Alternatively or additionally the display device may be operable to display the pre-set switching times. With regard to temperature, the display device may be operable to display current ambient temperature and/or the pre-set switching temperature. Presentation of information can be further promoted by virtue of the action of the audible signalling device which may be arranged to produce a tone or other audible signal for example whenever the manual controls are operated and/or when a pre-set time or temperature is reached.

The control unit of the invention can be manufactured and installed in a particularly simple, convenient and inexpensive manner yet may be a versatile unit capable of controlling a wide range of functions. Thus the control circuitry can be readily adapted to accommodate a wide range of timing cycles of daily or longer duration.

Similarly the unit can respond to a range of pre set temperatures such as a maximum desired room temperature, a minimum frost temperature, a maximum hot water tank temperature.

Moreover the control unit can be used for purposes additional to the control of a central heating system. By way of example, the unit may be used for any one or more of the following purposes: as a door bell, in which case a remote bell push connected to the unit may be operable to actuate the audible signalling device; as a smoke detector or fire alarm or burglar alarm, a remote sensor being used to operate the audible signalling device or to initiate some other warning or remedial action; as a timer for triggering desired operations (such as switching on of a domestic appliance, actuation of an alarm, random switching on of lights in an unoccupied house); a zero crossing point detector (i.e. a system which ensures that switch on of an electrical lamp or other appliance occurs only at the instant at which the supplied mains power is at the zero voltage point).

With regard to the construction of the control unit, this may take any suitable form but preferably the unit is suited to mounting of same in a sinking box of the kind used to mount domestic electrical sockets and the like. The manual controls may be touch switches which may be provided with associated indicator lamps. Such switches may be provided behind a hinged cover flap or the like.

The invention will now be described further by way of example only and with reference to the accompanying drawings in which: Fig. 1 is a diagrammatic perspective view of one form of a control unit according to the invention; and Fig. 2 is a circuit diagram of the unit.

The unit has a housing which may be in the form of a plastics box 1. In the upper region of a front face 2 of such box there is a rectangular aperture 3 through which a digital display device 4 can be viewed, such device having four 7segment digital display regions. Alongside this aperture 3 there is a further aperture through which projects a rotary spindle of a potentiometer, such spindle having a knob 5 thereon. In the lower region of the front face of the box there is an arrangement of multiple slots or other openings defining a grill 6, and also a recess 7 which can be covered with a hinged flap 8. Within the recess 7 there is a bank of touch sensitive switches 9, each such switch 9 comprising a metal ring 10 which is set within a respective aperture in the recessed region of the front face 2.Within some or all of these rings 10 there are respective lamps 11, such as lightemitting diodes (LEDs).

At the back of the box 1 there are electrical terminals (not shown in Fig. 1) to which leads 12, 1 3 can be connected.

The box 1 is constructed so that it can be mounted within a conventional sinking box of the kind used to wall-mount domestic electrical double sockets or the like.

Within the box, as indicated in Fig. 2, there is a printed circuit board having thereon electronic circuitry 14 utilising integrated circuit components and incorporating timing and memory circuits. The box 1 also contains a loudspeaker 1 5 mounted behind the grill 6, a temperature sensitive electrical component 1 6 also mounted behind the grill and the aforesaid potentiometer 17 controlled by the knob 5. The circuitry 14 is connected to the digital display device 4, the touch sensitive switches 9, the lamps 11 associated with the switches 9, the temperature sensitive components 16, the potentiometer 17, and the aforesaid electrical terminals at the back of the box, which terminals comprise earth, live power input, control signal output and auxiliary terminals 18, 19, 20, 21.

In use, for controlling a domestic hot water central heating system, the unit is mounted on a wall at a convenient prominent position, such as in a living room or hall, and the terminals 18-21 are connected via suitable said leads 12 to a control box 22 mounted on or adjacent the central heating boiler. The control box 22 contains a step-down mains transformer 23 and also relay devices 24, 25 which may be of any suitable electronic and/or electromagnetic construction. The transformer 23 is connected to mains supply and provides a low secondary voltage which is used to power the control unit, appropriate rectification and associated power supply components being incorporated in the circuitry 14.The relay devices 24, 25 have switching contacts which are connected in mains power supply circuits respectively for a fuel supply solenoid valve for the boiler and a water circulation pump of the heating system.

In use, the timing circuitry is operable to produce a display of current time on the display device 4 in the manner of a digital clock. The flap 8 can be hinged downwardly, as shown in Fig. 1, to expose the touch sensitive switches 9. By appropriate operation of these switches 9, the central heating system can be manually switched on and off and also pre-set times can be entered into the memory circuits corresponding to the times at which the boiler of the heating system is required automatically to switch on and off. These times are displayed on the device 4 during setting thereof and also can be recalled on demand as and when required. When not so recalled, the device 4 reverts to its display of current time.

Instructions for operation of the switches 9 may be printed on the inner surface of the flap 8. After setting of the desired time cycle, the flap 8 can be hinged upwardly to cover the switches 9.

The temperature at which the water circulation pump switches on and off can be pre-set by rotation of the knob 5. The knob 5 and the spindle on which it is mounted are metal and additionally act as a touch sensitive switch whereby, when the knob is touched, the display device 4 displays the pre-set temperature.

As mentioned above, some or all of the touch sensitive switches 9 have LEDs 11 associated therewith and these are illuminated when the pertaining switches 9 are actuated. Additionally, the circuitry includes an audio signal generator which actuates the loudspeaker 1 5 to give a short tone whenever any of the switches 9 is actuated.

A tone is also produced whenever the ambient temperature, as detected through the grill 6 by the temperature sensitive component 16, reaches the pre-set level and the water circulation pump is thereby switched off. Thus, the prevailing ambient temperature can be determined by rotating the knob 5 until a point is reached at which the tone is produced whereupon the ambient temperature will then be displayed on the device 4. The arrangement may be such that a series of repeated tones is produced if the knob 5 is manipulated to hold the pre-set temperature at the prevailing ambient level.

With the arrangement so far described, electrical installation work can be effected in a particularly simple and convenient manner having regard to the convenient mode of mounting the unit, and also having regard to the simplicity of the electrical connections and the fact that the leads between the unit and the control box are at low voltage levels.

Moreover, with the unit range of information comprising current time, pre-set switching times, pre-set switching temperature, prevailing ambient temperature can be displayed in a convenient and attractive manner.

Further, the unit is of a versatile nature and can be readily adapted at the manufacturing stage or subsequently to accominodate a wide range of requirements with regard to control of the central heating system and also for other purposes. Thus, the circuitry of the unit may be connected to further terminals to provide further output signals for controlling further mechanisms and/or to receive input signals from remote sensors or switches.

In one modification, a temperature sensitive component, such as a transistor may be used to monitor the temperature of a hot water tank and this component may be connected via a low voltage lead to an appropriate input of the unit, a suitable output of the unit being used to effect corresponding control of boiler water temperature or the like.

In a further modification, as shown in the drawings, a remote bell push 26 is connected by leads 13 to inputs 27 of the unit. When the bell push 26 is operated a suitable tone or combination of tones is produced by the loudspeaker 1 5. The unit can therefore function additionally as a door bell.

With regard to the nature of the electronic circuitry 14 it will be appreciated that this may take any suitable form but preferably comprises a m icro-processor-based circuit incorporating suitable memory, interface, driving and like components.

It is of course to be understood that the invention is not intended to be restricted to the details of the above embodiment which are described by way of example only.

Claims (filed 3/1/82) 1. A housed control unit for a central heating system having a digital display device, a temperature sensor, an audible signalling device, a power input, a control signal output, electronic control circuitry including memory and timing circuits connected to said devices, sensor, input and output, and manually operable controls for controlling operation of said circuitry, said circuitry being operable to feed switching control signals to said control signal output in dependence on operation of said manually operable controls and in dependence on the temperature as determined with said temperature sensor and the time as determined with said timing circuit, and said circuitry also being operable to effect production of a visual display on said digital display representative of time and/or temperature and to effect production of an audible signal with said audible signalling device in correspondence with operation of the unit.

2. A unit according to claim 1, wherein the display device is operable to provide a continuous or on-demand display of current time.

3. A unit according to claim 1 or 2, wherein the display device is operable to display pre-set switching times.

4. A unit according to any one of claims 1 to 3, wherein the display device is operable to display current ambient temperature.

5. A unit according to any one of claims 1 to 4, wherein the display device is operable to display a pre-set switching temperature.

6. A unit according to any one of claims 1 to 5, wherein said audible signalling device is arranged to produce an audible signal whenever the manual controls are operated.

7. A unit according to any one of claims 1 to 6, wherein said audible signalling device is arranged to produce an audible signal whenever a pre-set time or temperature is reached.

8. A unit according to any one of claims 1 to 7, wherein said manual controls are touch switches.

9. A unit according to claim 8, wherein said manual controls are arranged behind a hinged cover.

10. A unit according to claim 1, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

11. A unit according to any one of claims 1 to 10, when mounted in a sinking box.

1 2. A central heating system incorporating a unit according to any one of claims 1 to 11.

1 3. A system according to claim 12, wherein said control unit is located remote from a boiler of the system and operates at a low supply voltage received from a power supply unit having a stepdown mains transformer located in the vicinity of the boiler, said system also comprising one or

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. therewith and these are illuminated when the pertaining switches 9 are actuated. Additionally, the circuitry includes an audio signal generator which actuates the loudspeaker 1 5 to give a short tone whenever any of the switches 9 is actuated. A tone is also produced whenever the ambient temperature, as detected through the grill 6 by the temperature sensitive component 16, reaches the pre-set level and the water circulation pump is thereby switched off. Thus, the prevailing ambient temperature can be determined by rotating the knob 5 until a point is reached at which the tone is produced whereupon the ambient temperature will then be displayed on the device 4. The arrangement may be such that a series of repeated tones is produced if the knob 5 is manipulated to hold the pre-set temperature at the prevailing ambient level. With the arrangement so far described, electrical installation work can be effected in a particularly simple and convenient manner having regard to the convenient mode of mounting the unit, and also having regard to the simplicity of the electrical connections and the fact that the leads between the unit and the control box are at low voltage levels. Moreover, with the unit range of information comprising current time, pre-set switching times, pre-set switching temperature, prevailing ambient temperature can be displayed in a convenient and attractive manner. Further, the unit is of a versatile nature and can be readily adapted at the manufacturing stage or subsequently to accominodate a wide range of requirements with regard to control of the central heating system and also for other purposes. Thus, the circuitry of the unit may be connected to further terminals to provide further output signals for controlling further mechanisms and/or to receive input signals from remote sensors or switches. In one modification, a temperature sensitive component, such as a transistor may be used to monitor the temperature of a hot water tank and this component may be connected via a low voltage lead to an appropriate input of the unit, a suitable output of the unit being used to effect corresponding control of boiler water temperature or the like. In a further modification, as shown in the drawings, a remote bell push 26 is connected by leads 13 to inputs 27 of the unit. When the bell push 26 is operated a suitable tone or combination of tones is produced by the loudspeaker 1 5. The unit can therefore function additionally as a door bell. With regard to the nature of the electronic circuitry 14 it will be appreciated that this may take any suitable form but preferably comprises a m icro-processor-based circuit incorporating suitable memory, interface, driving and like components. It is of course to be understood that the invention is not intended to be restricted to the details of the above embodiment which are described by way of example only. Claims (filed 3/1/82)

1. A housed control unit for a central heating system having a digital display device, a temperature sensor, an audible signalling device, a power input, a control signal output, electronic control circuitry including memory and timing circuits connected to said devices, sensor, input and output, and manually operable controls for controlling operation of said circuitry, said circuitry being operable to feed switching control signals to said control signal output in dependence on operation of said manually operable controls and in dependence on the temperature as determined with said temperature sensor and the time as determined with said timing circuit, and said circuitry also being operable to effect production of a visual display on said digital display representative of time and/or temperature and to effect production of an audible signal with said audible signalling device in correspondence with operation of the unit.

more relays in the vicinity of the boiler which are arranged to effect switching of heating system components in response to actuation by control signals from said control unit.