GB2368925A

GB2368925A - A programmable cooker for heating a boiler or an oven

Info

Publication number: GB2368925A
Application number: GB0124123A
Authority: GB
Inventors: Michael Stack; Noel Hannan
Original assignee: Waterford Foundry Ltd
Current assignee: Waterford Foundry Ltd
Priority date: 2000-10-06
Filing date: 2001-10-08
Publication date: 2002-05-15
Anticipated expiration: 2021-10-08
Also published as: GB2368925B; IES20000806A2; GB0124123D0; IE20010886A1

Abstract

A cooker comprises at least one burner for heating a boiler or an oven. The control system 1 comprises a programmable computer 29 and a signal generating means for example a control knob. In use the cooker may provide heat for both an oven and a boiler to provide hot water for a domestic heating system. The operation of the cooker may be manual or programmed (for example switching on and off times). The cooker may be remotely operated for example via a telephone link. The system may further provide diagnostic information to a supplier at a remote location, and may be provided with corrective reprogramming from the said remote location. During operation in oven mode only, the system may open a valve to allow water to flow from the boiler into the heating system, should the temperature of the water in the boiler exceed a predetermined limit, as a result of residual heating from the oven. If the temperature of the water in the boiler is allowed to exceed said predetermined value a thermostat is triggered and the cooker shut down.

Description

IMPROVED COOKER The present invention relates to an improved cooker and more particularly to an improved cooker having a control system.

Range cookers are currently controlled by a combination of thermostats and a timer. A large number of thermostats are required to control a cooker having an oven for domestic cooking and a boiler for providing the domestic water and central heating water. Oven and boiler control thermostats are located in the oven and boiler respectively, in addition to a thermostat to control a circulating pump for the central heating water. A further thermostat is required to open a motorised valve to dump water down the heating system during the summer when the cooker is used mostly for domestic hot water and cooking. This thermostat prevents the cooker shutting down due to residual heat from the oven heating the water in the boiler above a shut down temperature. Additionally, a rocker switch is required to switch the timer between domestic hot water mode and domestic hot water and central heating mode. The thermostats and the timer are currently connected by hard wiring and the thermostats are set value mechanical controls providing a coarse method of maintaining the system at a constant temperature.

There is clearly a need for a more adjustable control system over a greater range of operating values in combination with a more compact unit having a reduced number of parts.

Accordingly, there is provided a cooker comprising at least one burner for heating a boiler or oven, a control system having a signal generating means and a cooker computer for switching the burner between an off position and an on position, wherein the computer is in communication with and responds to the signal generating means, the signal generating means including a control element within the oven or boiler, a program stored in the memory of the computer and input means on the computer for controlling the function and operation of the cooker. Preferably, the input means is operable separately by a remote terminal.

Remote control of the cooker provides greater flexibility for an operator who no longer needs to be at home to pre-heat an oven or boost the hot water. Additionally, remote control of a cooker in a house provides the operator with an effective and inexpensive method of counteracting freezing conditions in the area where the house is located reducing the risk of burst pipes and house floods in extreme weather conditions.

In a preferred embodiment, the cooker comprises two burners, one for heating a boiler and the second for heating an oven respectively. Two burners provide a complete heating and cooking solution for domestic and commercial dwellings.

Preferably, the cooker is operable by gas or oil. A variety of gas and oil burners may be used in combination with the cooker to allow more versatility for the end user.

Ideally, the gas cooker incorporates a gas burner using pre-mix burner technology. This burner will automatically shut down if the exhaust flue is partially blocked or if the ratio of air to gas reaches a value at which the gas will no longer ignite. Advantageously, the pre-mix burners are cheaper, smaller and quieter.

Preferably, the control system incorporates a PCB (Printed Circuit Board) having a plurality of connectors for attaching all the elements of the control system.

Ideally, screw terminal or plug-in connection points are provided on the PCB for a flue fan, a circulating pump, a domestic hot water valve, a central heating valve and burners.

Preferably, the control system further incorporates a cylinder thermostat, room thermostats, high limit thermostats and optoelectronic sensors.

Ideally, when the cooker is fuelled by gas the signal means further incorporates air pressure switches.

Preferably, the same PCB board can be used for the oil cooker and the gas cooker. The computer program can be set up to ignore input from the air pressure switches when the computer is controlling an oil cooker.

Ideally, the circulating pump pumps water which is heated in the boiler through the central heating system and the domestic hot water cylinder.

Preferably, the circulating pump can continue to operate when the high level thermostats are activated.

Preferably, the high level thermostats shut the cooker down in response to a predetermined temperature being reached. A signal from the remote transmitter or any of the other signal means will not compromise the integrity of the high level thermostats. Once the high level thermostat is activated a reset button on the thermostat must be manually pressed before any further operation of the cooker can occur.

Preferably, the flue fan is powered in response to either burner starting up.

Ideally, the domestic hot water valve is closed in response to a signal from the domestic water cylinder thermostat reaching a predetermined temperature thereby preventing any further hot water passing through the domestic water cylinder.

Preferably, the central heating valve prevents any water passing into the central heating system when in a closed position and it is closed in response to a signal from the room thermostats when they have reached a predetermined temperature. This prevents any further hot water entering the central heating system.

Ideally, the optoelectronic sensors provide diagnostic information in relation to where the malfunction of the cooker has occurred.

In one embodiment, the information received by the optoelectronic sensor is deciphered by a pair of LED's, one of the LED's being a high speed infra red data transmitter LED and the other optoelectronic sensor is provided by a lockout indicating red LED.

Preferably, the diagnostic information is displayed on the LCD located on the cooker computer.

Preferably, the cooker computer has a programmable memory for independently controlling a cooking channel, a central heating channel and a domestic hot water channel. The computer allows an extra channel to be controlled independently when compared with the timer and thermostat cooker control system which is currently available.

Ideally, the three channels are programmable using input buttons on the computer to set the on and off times for each channel.

Alternatively, the three channels are activated from the remote terminal. This facility provides an operator with greater flexibility and adaptability and places less significance on manual control of both cooking and heating.

Preferably, the domestic water channel and the central heating channel are programmable for seven days and the program is repeatable.

Ideally, the cooking channel is programmable for one day with a limit of three on/off times.

Ideally, manual control of the cooker is provided by a number of input elements on the exterior of the cooker computer including temperature dials for the oven and the boiler and boost buttons for the domestic hot water channel and the central heating channel.

Preferably, the oven and the boiler are heated to the temperature set by the respective temperature dials on the cooker computer when the cooker is on programmed mode. Preferably, the boost buttons turn the burners on for thirty minutes each time the boost button is pressed up to a maximum of two hours and the fifth pressing of the boost button resets the boost time to zero.

Ideally, the oven channel can be switched to manual using an input button on the computer in conjunction with turning the temperature dial for the oven to the desired temperature.

Preferably, the control element within the oven is provided by a thermocouple and the control element within the boiler is provided by a thermistor. The thermistor and thermocouple provide more control over a wide range of temperatures as opposed to the set values of the mechanical thermostat. Additionally, the parameters of control can be adjusted to suit the requirements of the system. The use of thermocouples and thermistors also reduce the number of thermostats required and remove the hardwiring between those thermostats and the removed timer. This reduction of parts brings about a substantial reduction in the overall cost of the control system for the cooker.

Ideally, the computer continuously monitors the readings from the thermocouple, thermistor and the air pressure switches. This allows the control system to respond rapidly to any critical or important values being reached.

Ideally, the thermistor signals the computer which turns on the circulating pump when the temperature of the water in the boiler reaches 55 degrees Celsius. This prevents dew point being reached in the vicinity of the boiler preventing rusting of the boiler.

Preferably, the thermistor signals the computer which opens the central heating valve when the cooker is on oven mode only and the water in the boiler reaches eighty-five degrees Celsius

due to residual heat from the oven. This prevents the temperature in the boiler reaching ninety degrees Celsius and triggering the high limit thermostat which results in shut down of the entire cooker.

In a further aspect of the invention, the computer in communication with the thermistor controls the circulating pump to continue operating for a predetermined period of time only after the boiler burner has been shut down and the domestic water and central heating valves have been closed. This predetermined period of time will prevent any residual heat causing a significant rise in boiler temperature. At present the circulating pump continues to run until the temperature of the water in the boiler falls to 55 degrees Celsius. This calculated predetermined run time for the pump will greatly reduce the amount of time the pump runs after shut down of the burner thereby improving the efficiency of the overall heating system.

Ideally, the remote terminal is provided by any touch tone telephone, a mobile phone, a control pad in another part of the house, a remote computer terminal or by conventional remote control depending on the user requirements.

In one embodiment, the cooker supplier can access the cooker from their premises allowing the supplier to re-program the cooker in the event of a malfunction. Beneficially, this allows the supplier to observe the service history of the cooker speeding up the repair process.

In a further aspect of the invention, the electricity supplier has remote access to the cooker allowing the supplier to overcome problems with peak demand in certain areas by reprogramming the cooker to alter the on/off times of the cooker.

Preferably, the remote computer terminal can access the cooker computer via a modem, an ISDN (Integrated Services Digital Network) line, the Internet or any such data link.

In a particularly preferred embodiment, the cooker computer is accessed via RAPT (Remote Activation Paging Technology) technology. Preferably, the cooker computer also provides a LCD (Liquid Crystal Display) which displays the operational status of the cooker and any fault conditions as a result of the information generated by the optoelectronic sensors.

Preferably, the computer is operated from low voltages ( < 12volt) only, and connected by a single multiway cable and a connector. The computer is located on a punched metal plate, which is a snug fit in a control recess area of the cooker.

Ideally, the plate is covered by a printed graphic overlay, with embossed or tactile push buttons, slide switches and a transparent window. The control system PCB is mounted behind the plate on standoffs.

Preferably, the major components on the computer is a microprocessor and a LCD display.

The LCD is visible through the window in the graphic overlay.

Preferably, the LCD display is backlit. The computer has a backup battery and the controls are potentiometers.

Ideally, software is custom designed. Extra hardware facilities are included to allow for future developments.

Preferably, the burner control and interface assembly PCB is a printed circuit assembly with input/output connectors. This PCB may be situated in the burner control tray and use of microcontrollers is avoided to ease safety standards. The control logic is designed to incorporate a degree of self-checking, and critical circuits are designed to be fail-safe.

Ideally, internal connections on the burner PCB can be either screw terminal or by connector.

Ideally, the features of the printed circuit board of the control system include a 12 volt and/or 5 volt DC power supply (depending upon backlight chosen), control logic integrated circuits and relays for"outside world interface.

Additionally, the printed circuit board includes connections to the computer (all low voltages), two air pressure proving switches (mains voltages), two burner connectors (mains voltages), limit thermostats (mains voltages), control thermistor/thermocouple (low voltages), mains supply, fan flue, cylinder thermostat, pipe thermostat, room thermostat, central heating valve, domestic hot water valve and circulating Pump.

The wiring to the various devices is greatly simplified.

Ideally, the cooker control has one minute setting accuracy with 3 on-off cooker times.

Preferably, there are 72 timer pegs, giving 20 minutes resolution to the central heating (CH) and domestic (DHW) programs. It is not necessary to have a full seven-day programming facility for the cooker.

Ideally, the cooker Computer control system may be supplied in two (or three) parts: 1. the programmer; 2. the burner interface; and 3. the I/O terminals.

Other major benefits will be better serviceability and a totally new concept control with more attractive features than any cooker control on the market. Also, the wiring is much tidier and the electronics PCBs will be simple plug in replacement in the unlikely event of problems.

Additionally, the computer will be software upgradable, for future products and cleaning and servicing the computer will be safer as there is no mains voltages present.

The invention will now be described with reference to the accompanying drawings, which show, by way of example only, one embodiment of an improved cooker in accordance with the invention in which: Figure 1 is a diagram of a control system for the improved cooker fuelled by oil ; Figure 2 is a diagram of a control system for the improved cooker fuelled by gas; Figure 3 is a diagram of a control system for the improved cooker; Figure 4A is a simplified diagram showing the wiring harness routes with the present twin burner cooker; and Figure 4B shows the simplification of the wiring due to the cooker control system.

Referring to the drawings and now to Figure 1 and Figure 3, there is shown a diagram of a control system for a twin series oil cooker indicated generally by the reference numeral 1. The details of the operation of the cooker 1, from plugging in the appliance to full operational mode, are set out below. The details of the cooker per se are not shown in the drawings as they are well known in the art. Suitable cookers are the cast-iron cookers manufactured and sold under the trade mark STANLEY by Waterford Stanley Limited.

Upon power up of the cooker 1 the main power supply P. C. B. board 22 is engaged. The phase 23 runs through the amp fuse 24 on to other connection points within the board, such as fan flue 2 and fan flue 3. The flue fan gets a signal as soon as either burner is turned on. The phase 23 also goes to both the oven high limit thermostat 25 and the boiler high limit

thermostat 27, the boiler control box 37 and the oven control box 36. The relays 141 to 147 and all the connectors on the right hand side of the board except the neutral points 35 are supplied with phase. There are seven relays, namely an oven control box relay 141, a boiler control box relay 142, a central heating valve relay 143, a pump relay 144, a reset relay 145, a heat dissipation relay 146 and a fan relay 147. The phase is passed through a step down transformer 51 to provide the remaining components with a low voltage (approx. 12 V) power supply. The low voltage power supply passes to the computer 29, the thermistor 42, the thermocouple 41 and the optoelectronic sensors 13 and 14.

The neutral 35 is connected to each relay 141 to 147 and to four other neutral pick-up points 35 on the main PCB board 22. The neutral 35 also passes to both the boiler control box 36 and oven control box 37.

The earth is connected as a separate earth block (solid metal bonding post type) fixed to the metal work of the cooker 1. It is linked by a wiring loom harness to all electrical parts such as high limit thermostats 25,27, control boxes 36,37 and the cooker chassis to ensure electrical safety at all times.

The computer 29 independently operates a cooking channel, a domestic hot water channel and a central heating channel on the modes day off, continuous, auto, boost and can be set up to three different times on each channel for the same time each day or different times each day.

Once oven mode is engaged either manually, remotely or in response to a pre-set programme stored in the computer 29, a signal is put out from a terminal on the computer 29 to both the thermocouple 41 and to a connection on the main PCB board 22. The signal also goes to oven control box relay 141, fan relay 147 and cylinder thermostat 5. If the cylinder thermostat 5 is closed or if the cylinder thermostat link 6 is in place power will arrive on to the domestic hot water valve connection point 7. Where a cylinder thermostat is used, it replaces the link wire fitted between the terminals 5 and 6. If the cylinder thermostat is closed then the domestic hot water valve gets phase and therefore opens. When the cylinder thermostat reaches a pre-set

temperature the link between terminals 5 and 6 is no longer made. Phase to the domestic hot water valve is interrupted and water in the cylinder is prevented from circulating through the boiler. The computer 29 constantly monitors the value of the thermistor 42 and the thermocouple 41. If the thermocouple 41 reports a temperature to the computer 29 less than the temperature setting on a temperature dial on the cooker, the computer 29 will signal the oven control box relay 141. Power will arrive onto a connection on the oven control box 36 which will begin start up and the oven fan motor 61 will start. A transformer begins sparking and a photocell checks for no light. A valve opens to deliver oil and the photocell again checks for light. A typical oven control box 36 to be used in this control system is a SATRONIC DK 0970.

If the thermocouple 41 fails (closed circuit) and the oven burner continues to generate heat, the oven high limit thermostat 25 will open and shut down the cooker 1 and all workings down stream of the limit thermostat 25. When the appliance cools down it must be manually reset by pressing a button on the front face of the thermostat 25.

Once central heating mode is engaged, a signal is put out from a terminal on the computer 29 and goes to boiler control box relay 142, central heating valve relay 143, fan relay 147 and to burner control link 11,12. Burner control link 11,12 provides an external method of disrupting power to the burners. At the same time power goes on to the room thermostat terminal link 8 and 9. If the thermistor 42 is reporting a temperature to the computer 29 less than the predetermined temperature stored in the computer 29, the computer 29 will signal the boiler control box relay 142 and power will arrive onto a connection on the boiler control box 37 which will begin start up.

Fan motor 62 starts and a transformer begins sparking. A photocell checks for no light and valves open to deliver oil. The photocell checks again for light.

When the temperature of the water in the boiler reaches 55 C the computer 29 sends a signal to the pump relay 144 switching the circulating pump 31, 32 on. At 55 C the phenomenon of dew point is avoided reducing the harmful effects of rusting on the boiler. Dew point would occur about the water-jacket of the burner in the region where cold water entering the boiler encounters warm water that has just been heated by the boiler. When the temperature of the water in the boiler reaches 80oC, the computer 29 signals the boiler control box 36 via relay 142 to shut down the boiler burner. The temperature of the water at which the computer 29 signals the boiler control box 36 to restart the boiler burner is set at approximately 76 C (approx. 4 C below cut out temperature). Additionally, when the pre-set temperatures are reached in the relevant zones or rooms the room thermostats 8,9 may operate relays that shut off the relevant zones or the room thermostats 8,9 may directly shut the boiler burner down by means of burner link 11,12.

If the thermistor 42 fails (closed circuit) and the boiler burner continues the boiler high limit thermostat 27 will open and shut down the cooker 1 and all workings down stream of the limit thermostat 27 at approximately 90oC. When the appliance cools down it must be manually reset by pressing a button on the front face of the thermostat 27.

Once domestic hot water mode is engaged a signal is put out from a terminal on the computer 29 and it goes to boiler control box relay 142, fan relay 147, cylinder thermostat 5 and to burner control link 11 and 12. If the cylinder thermostat 5 is closed or if the cylinder thermostat link 6 is in place power will arrive on to the domestic hot water valve connection point 7. This valve prevents the water which is heated in the boiler passing into the domestic water cylinder. If the thermistor 42 is reporting a temperature to the computer less than the predetermined temperature stored in the computer 29, the computer 29 will signal the boiler control box relay 142 and power will arrive onto a connection on the boiler control box 37 which will begin start up.

The fan motor 62 starts and a transformer begins sparking. A photocell checks for no light and valves open to deliver oil. The photocell checks again for light.

When the temperature of the water in the boiler reaches 55 C the computer 29 sends a signal to the pump relay 144 switching the circulating pump 31,32 on. When the temperature of the

water in the boiler reaches 80 C the computer 29 signals the boiler control box 36 via relay 142 to shut down the boiler burner. The temperature of the water at which the computer 29 signals the boiler control box 36 to restart the boiler burner is set at approximately 76 C (approx. 4 C below cut out temperature). Once the pre-set temperature is reached in the domestic hot water cylinder, the cylinder thermostat breaks the link between 5 and 6 to shut the domestic hot water valve 7 preventing hot water from passing through the domestic hot water cylinder.

The circulating pump 31,32 will continue to operate, if any of the high limit thermostats 25, 27 are open.

Referring to the drawings and now to Figure 2 and Figure 3 there is shown a diagram of a control system for a twin burner gas cooker indicated generally by the reference numeral 21.

The operations of the gas cooker from plugging in the appliance to full operational mode are set out below.

Upon powerup of the cooker 21 the main power supply P. C. B. board 22 is engaged. The phase 23 runs through the amp fuse 24 on to other points within the board, such as fan flue 2 and fan

flue 3. The flue fan gets a signal as soon as either burner is turned on. The phase 23 also goes to both the oven high limit thermostat 25 and the boiler high limit thermostat 27 and the boiler control box 37 and the oven control box 36. The relays 141 to 147 and all the connectors on the right hand side of the board except the neutral points 35 are supplied with phase as well as both the boiler pressure switch 101 and oven pressure switch 102. There are seven relays, namely an oven control box relay 141, a boiler control box relay 142, a central heating valve relay 143, a pump relay 144, a reset relay 145, a heat dissipation relay 146 and a fan relay 147. The phase is passed through a step down transformer 51 to provide the remaining components with a low voltage (approx. 12 V) power supply. The low voltage power supply passes to the computer 29, the thermistor 42, thermocouple 41 and the optoelectronic sensors 13 and 14.

The neutral 35 is run to each relay 141 to 147 and from there to four other neutral pick-up points 35 on the main PCB board 22. The neutral 35 also passes to the boiler control box 36 and oven control box 37.

The earth is connected as a separate earth block (solid metal bonding post type) fixed to the metal work of the cooker. It is linked by a wiring loom harness to all electrical parts such as high limit thermostats 25,27, control boxes 36,37 pressure switches 101,102 and the cooker chassis to ensure electrical safety at all times.

The computer 29 independently operates a cooking channel, a domestic hot water channel and a central heating channel on the modes day, off, continuous, auto, boost and can be set up to three different times on each channel for the same time each day or different times each day.

When the oven mode is engaged either manually, remotely or in response to a pre-set programme stored in the computer 29, a signal is put out from a terminal on the computer 29 to both the thermocouple 41 and a connection on the main PCB board 22. The signal also goes to oven burner relay 141, fan relay 147 and cylinder thermostat 5. If the cylinder thermostat 5 is closed or if the cylinder thermostat link 6 is in place power will arrive on to the

domestic hot water valve connection point 7. The computer 29 constantly monitors the thermistor 42, the thermocouple 41 and both pressure switches 101,102. If the thermocouple 41 reports a temperature to the computer 29 less than the temperature setting on a temperature dial on the cooker the computer will signal the oven control box relay 141. Power will arrive onto a connection on the oven control box 36 which will begin start up and the oven burner fan motor 61 and oven pressure switch 102 are engaged (closed). Each gas burner has a fan and an associated pressure switch 101, 102.

The pre-purge period will last approximately 30 seconds and the control box 36 will lock out at this stage if the pressure switch 102 is not closed.

Within the control box 36, a transformer provides a voltage to an ignition electrode causing a spark to jump from an ignition probe to the burner head. During this section a gas valve opens while the ignition electrode continues to spark. An ionisation/flame signal is checked. With the burner firing at the start of this section all checks have been carried out and found to be satisfactory.

If the thermocouple 41 fails (closed circuit) and the oven burner continues to generate heat, the oven high limit thermostat 25 will open and shut down the cooker 21 and all workings down stream of the limit thermostat 25. When the appliance cools down it must be manually reset by pressing a button on the front face of the thermostat 25.

Once central heating mode is engaged, a signal is put out from a terminal on the computer 29 and goes to boiler burner relay 141, central heating valve relay 143, fan relay 147 and to burner control link 11,12. Burner control link 11,12 provides an external method of disrupting power to the burners. At the same time power goes on to the room thermostat terminal link 8 and 9. If the thermistor 42 is reporting a temperature to the computer 29 less than the predetermined temperature stored in the computer 29, the computer will signal the boiler control box relay 142 and power will arrive onto a connection on the boiler control box 37

which will begin start up. At this point the boiler burner fan motor 62 and boiler pressure switch 101 are engaged (closed).

The pre-purge period will last approximately 30 seconds. The control box 37 will lock out at this stage if the pressure switch 101 is not closed. The transformer provides a voltage to the ignition electrode causing a spark to jump from the ignition probe to the burner head. During this section the gas valve opens while the ignition electrode continues to spark. The ionisation/flame signal is checked. With the burner firing at the start of this section all checks have been carried out and found to be satisfactory.

water in the boiler reaches 80 C the computer 29 signals the boiler control box 36 via relay 142 to shut down the boiler burner. The temperature of the water at which the computer 29 signals the boiler control box 36 to restart the boiler burner is set at approximately 76 C (approx. 4 C below cut out temperature). Additionally, when the pre-set temperatures are reached in the relevant zones or rooms the room thermostats 8,9 may operate relays that shut off the relevant zones or the room thermostats 8,9 may directly shut the boiler burner down.

If the thermistor 42 fails (closed circuit) and the boiler burner continues the boiler high limit thermostat 27 will open and shut down the cooker 21 and all workings down stream of the limit thermostat 27 at approximately 90oc. When the appliance cools down it must be manually reset by pressing a button on the front face of the thermostat 27.

Once domestic hot water mode is engaged a signal is put out from a terminal on the computer 29 and it goes to boiler control box burner relay 142, fan relay 147, cylinder thermostat 5 and to burner control link 11 and 12. If the cylinder thermostat 5 is closed or if the cylinder thermostat link 6 is in place power will arrive on to the domestic hot water valve connection point 7. If the thermistor 42 is reporting a temperature to the computer 29 less than the

predetermined temperature stored in the computer 29, the computer 29 will signal the boiler control box relay 142 and power will arrive onto a connection on the boiler control box 37 which will begin start up.

At this point both the boiler burner motor fan 62 and the boiler pressure switch 101 are engaged (closed). The pre-purge period will last approximately 30 seconds. The control box 37 will lock out at this stage if the pressure switch 101 is not closed. The transformer provides a voltage to the ignition electrode causing a spark to jump from the ignition probe to the burner head. During this section the gas valve opens while the ignition electrode continues to spark. The ionisation/flame signal is checked. With the burner firing at the start of this section all checks have been carried out and found to be satisfactory When the temperature of the water in the boiler reaches 55 C the computer 29 signals the pump relay 144 switching the circulating pump 31,32 on. When the temperature of the boiler

reaches 80 C the computer 29 signals the boiler control box 36 via relay 142 to shut down the boiler burner. The temperature of the water at which the computer 29 signals the boiler control box 36 to restart the boiler burner is set at approximately 76 C (approx. 4 C below cut out temperature). Once the pre-set temperature is reached in the domestic hot water cylinder the cylinder thermostat breaks the link between 5 and 6 to shut the domestic hot water valve 7 preventing hot water from passing through the domestic hot water cylinder.

If the thermistor 42 fails (closed circuit) and the boiler burner continues the boiler high limit thermostat 27 will open and shut down the cooker 21 and all workings down stream of the limit thermostat 27 at 90oC. When the appliance cools down it must be manually reset by pressing a button on the front face of the thermostat 27.

If a malfunction occurs during operation of the cooker 21 the boiler optoelectronic sensor 13 and the oven optoelectronic sensor 14 will relay the information to the computer 29. A table

of the diagnostic conditions that may be extracted and displayed is supplied at the end of the detailed description of this specification.

Normally in the summer time when the appliance is being used for domestic hot water mode and cooker mode only, the computer 29 may signal the central heating valve relay 143 to open allowing hot water to pass into the heating system in response to the thermistor 42 reporting a

water temperature of 85 C in the boiler. This feature prevents residual heat from the oven heating the water in the boiler to approximately 90 C thereby causing the appliance to cut out during cooking.

Referring to the drawings and now to Figure 4A, the cooker is controlled by a combination of thermostats and a timer 429. An oven control thermostat 441 and boiler control thermostats 442 are located in the oven and boiler respectively in addition to a well thermostat 443 to control a circulating pump for the central heating and domestic hot water. A further inter thermostat 444 is required to open a motorised valve to dump water down the heating system during the summer when the cooker is used mostly for domestic hot water and cooking. This thermostat 444 prevents the cooker shutting down due to residual heat from the oven heating the water in the boiler above a shut down temperature. Additionally, a rocker switch is required to switch the timer 429 between domestic hot water mode and domestic hot water and central heating mode. The thermostats and the timer 429 are currently connected by a substantial amount of hard wiring as can be seen from the drawing. A main PCB board 445 having connectors for attaching external units and a secondary PCB board 446 for connecting to the oven control box 436, boiler control box 437and both burners 447,448 are also required. The limit thermostats 425 and 427 are connected to the main PCB board 445 and the pressure switches 401,402 are connected to the secondary board 446. Referring to the drawings and now to Figure 4B, the thermistor 42, thermocouple 41, oven control box 36, boiler control box 37, air pressure switches 101,102 and limit thermostats 25, 27 are all directly connected to the single control system PCB 22. The values provided by the thermistor 42, thermocouple 41 and air pressure switches 101,102 are monitored by the computer 29 and the system is controlled by the computer 29 in response to these values.

Table 1. Diagnostic conditions of Cooker

Fault Nr Test Possible cause 1 Oven. No air Welded Air Switch/faulty fan relay 2 Oven air Open air switch 3 Oven burner control Faulty burner control box/relay 4 Oven Hi-Limit thermostat Over temperature due to control thermostat failure 5 Oven Temperature sensor Faulty temperature sensor 6 Tek self-test Fail self test 7 Boiler Test No air Welded Air Switch 8 Boiler Air test Open air switch 9 Boiler burner control box Faulty burner control box 10 Boiler High limit thermostat Over temperature due to control thermostat failure 11 Boiler temperature sensor Faulty temperature sensor 12 Control tray temperature Excessive temperature in control tray 13 Low mains voltage Low supply 14 Oven flame not established in Ts No fuel/faulty valve 15 Oven flame simulation during Faulty flame probe/sensor Tw 16 Boiler flame not est. in Ts No fuel/faulty valve 17 Boiler flame simulation during Faulty flame proble/sensor Tw It is to be understood that the invention is not limited to the specific details described above, which are given by way of example only, and that various modifications and alterations are possible without departing from the scope of the invention as defined in the appended claims.

Claims

CLAIMS 1. A cooker comprising at least one burner for heating a boiler or oven, a control system having a signal generating means and a cooker computer for switching the burner between an off position and an on position, wherein the computer is in communication with and responds to the signal generating means, the signal generating means including a control element within the oven or boiler, a program stored in the memory of the computer, and input means on the computer for controlling the function and operation of the computer.
2. A cooker as claimed in Claim 1, in which the input means is operable separately by a remote terminal.
3. A cooker as claimed in Claim 1 or Claim 2, comprising two burners, one for heating a boiler and the second for cooking purposes and with the cooker being operable by gas or oil.
4. A cooker as claimed in any one of the preceding claims, in which the cooker incorporates a gas burner incorporating a pre-mix burner means, by which the burner will shut down if the exhaust flue is partially blocked or if the ratio of air to gas reaches a value at which the gas will no longer ignite.
5. A cooker is claimed in any one of the preceding claims, in which the control system incorporates a PCB (printed circuit board) having a plurality of connectors for attaching all the elements of the control system, with screw terminal or plug-in connection points being provided on the PCB for a flue fan, a circulating pump, a domestic hot water valve, a central heating valve and burners.
6. A cooker as claimed in any one of the preceding claims, in which the control system further incorporates a cylinder thermostat, room thermostats, high limit thermostats and optoelectronic sensors.
7. A cooker as claimed in any one of the preceding claims, in which the signal means further incorporates air pressure switches for use in conjunction with a gas burner
8. A cooker as claimed in Claim 6, including a circulating pump operable to pump water heated in the boiler through a central heating system and a domestic hot water cylinder, the circulating pump being operable to continue functioning when high level thermostats are activated with the high level thermostats being operable to shut the cooker down in response to a predetermined temperature being reached, with a reset means being operable on the thermostat and which must be manually pressed before any further operation of the cooker can occur.
9. A cooker as claimed in Claim 6, in which the domestic hot water valve is closable in response to a signal from the domestic water cylinder thermostat reaching a predetermined temperature thereby preventing any further hot water passing through the domestic water cylinder.
10. A cooker as claimed in Claim 6, in which the central heating valve is operable to prevent any water passing into the central heating system when in a closed position and is closable in response to a signal from the room thermostats when they have reached a predetermined temperature, thereby preventing any further hot water entering the central heating system.
11. A cooker as claimed in Claim 6, in which the optoelectronic sensors are operable to provide diagnostic information in relation to where a malfunction of the cooker has occurred.
12. A cooker as claimed in Claim 11, including a pair of LED's for displaying the information received by the optoelectronic sensors, one of the LED's being a high speed infra red data transmitter LED and the other being a lockout indicating red LED.
13. A cooker as claimed in Claim 12, in which the diagnostic information is displayable on an LCD located on the cooker computer.
14. A cooker as claimed in any one of the preceding claims, in which the cooker computer has a programmable memory for independently controlling a cooking channel, a central heating channel and a domestic hot water channel.
15. A cooker as claimed in Claim 14, in which the three channels are programmable using input controls on the computer to set the on and off times for each channel.
16. A cooker as claimed in Claim 14 or Claim 15, in the three channels are operable from the remote terminal.
17. A cooker as claimed in any one of the Claims 14 to 16, in which the domestic water channel and the central heating channel are programmable for seven days and the program is repeatable.
18. A cooker as claimed in any one of Claims 14 to 17, in which, the cooking channel is programmable for one day with a limit of three on/off times.
19. A cooker as claimed in any one of the preceding claims, in which manual control of the cooker is provided by a number of input elements on the exterior of the cooker computer including temperature dials for the oven and the boiler and boost buttons for the domestic hot water channel and the central heating channel.
20. A cooker as claimed in Claim 19, in which the oven and the boiler are heated to the temperature set by the respective temperature dials on the cooker computer when the cooker is on programmed mode.
21. A cooker as claimed in Claim 19 in which the boost buttons turn the burners on for thirty minutes each time the boost button is pressed, up to a maximum of two hours and the fifth pressing of the boost button resets the boost time to zero.
22. A cooker as claimed in Claim 19, in which, the oven channel can be switched to manual using an input button on the computer in conjunction with turning the temperature dial for the oven to the desired temperature.
23. A cooker as claimed in any one of the preceding claims, in which the control element within the oven is provided by a thermocouple and the control element within the boiler is provided by a thermistor.
24. A cooker as claimed in Claim 23, in which in use the computer continuously monitors the readings from the thermocouple, thermistor and the air pressure switches.
25. A cooker as claimed in Claim 23 or Claim 24, in which in use, the thermistor signals the computer which turns on the circulating pump when the temperature of the water in the boiler reaches 55 degrees Celsius, thereby preventing dew point being reached in the vicinity of the boiler preventing rusting of the boiler.
26. A cooker as claimed in Claim 23 or Claim 24, in which in use, the thermistor signals the computer which opens the central heating valve when the cooker is on oven mode only and the water in the boiler reaches eighty-five degrees Celsius due to residual heat from the oven, thereby preventing the temperature in the boiler reaching ninety degrees Celsius and triggering the high limit thermostat which results in shut down of the entire cooker.
27. A cooker as claimed in Claim 23, in which the computer in communication with the thermistor controls the circulating pump to continue operating for a predetermined period of

time only after the boiler burner has been shut down and the domestic water and central heating valves have been closed, thereby preventing any residual heat causing a significant rise in boiler temperature.
28. A cooker as claimed in any one of the preceding claims, in which the remote terminal is provided by touch tone telephone, a mobile phone, a control pad in another part of the house, a remote computer terminal or by any other remote control means.
29. A cooker as claimed in any one of the preceding claims, in which the cooker supplier can access the cooker from their premises allowing the supplier to re-program the cooker in the event of a malfunction and allowing the supplier to observe the service history of the cooker speeding up the repair process.
30. A cooker as claimed in any one of the preceding claims, in which the electricity supplier has remote access to the cooker allowing the supplier to overcome problems with peak demand in certain areas by reprogramming the cooker to alter the on/off times of the cooker.
31. A cooker as claimed in any one of the preceding claims, in which the remote computer terminal can access the cooker computer via a modem, an ISDN (Integrated Services Digital Network) line, the Internet or any such data link.
32. A cooker as claimed in any one of the preceding claims, in which the cooker computer is accessed via RAPT (Remote Activation Paging Technology) technology.
33. A cooker as claimed in any one of the preceding claims, in which the cooker also inlcudes a LCD (Liquid Crystal Display) which displays the operational status of the cooker and any fault conditions as a result of the information generated by the optoelectronic sensors.
34. A cooker as claimed in any one of the preceding claims, in which the computer is operated from a low voltage only, and electricity supply is connected by a single multiway cable and a connector.
35. A cooker as claimed in any one of the preceding claims, in which the computer is mounted on a plate which is covered by a printed graphic overlay, with embossed or tactile push buttons, slide switches and a transparent window with the control system PCB being mounted behind the plate on standoff.
36. A cooker as claimed in any one of the preceding claims, in which the printed circuit board includes connections to the computer, two air pressure proving switches (mains voltage), two burner connectors (mains voltage), limit thermostats (mains voltage), control thermistor/thermocouple (low voltage), mains supply, fan flue, cylinder thermostat, pipe thermostat, room thermostat, central heating valve, domestic hot water valve and circulating Pump.
37. A cooker substantially as herein described with reference to and as shown in the accompanying drawings.
38. A control system for use with a cooker as claimed in any one of the preceding claims.