WO2007028175A1

WO2007028175A1 - A heating device

Info

Publication number: WO2007028175A1
Application number: PCT/ZA2006/000103
Authority: WO
Inventors: Andre Meinhard Fourie
Original assignee: Andre Meinhard Fourie
Priority date: 2005-09-02
Filing date: 2006-09-01
Publication date: 2007-03-08
Also published as: AU2006287152A1; EP1938020A1; ZA200710543B; AU2006287152A2; ZA200710542B

Abstract

The invention provides for a heating device control system 10. The system 10 includes a temperature sensor 21 arranged to measure a temperature of a liquid when heated by a heating device, such as a hot water cylinder 12. The system 10 includes a control arrangement arranged to monitor pre-determined parameters, such as a heating rate, associated with heating of the heating device 12 and to interrupt electrical current supply to a heating element 25 of the heating device 12 should any one of the monitored parameters deviate from a pre-determined amount. The system 10 further includes a remote indication device 16 operatively associated with the control arrangement and arranged to indicate to a user that electrical current supply to the heating element 25 of the heating device 12 has been interrupted.

Description

A HEATING DEVICE

FIELD OF THE INVENTION:

THIS INVENTION relates to a heating device. In particular, the invention relates to a method of regulating heating of a heating device, to a heating device control system and to a heating device.

BACKGROUND OF THE INVENTION:

Heating devices are used in a variety of different applications. Such heating devices include water heating devices, such as, geysers, hot water earns, bane maries, instant water heaters, water heaters for Jacuzzis and saunas, and the like, for example. Such heating devices further include heating devices used in hot houses, aquariums, air conditioning, refrigeration and the like, for example.

Geysers are often used as water heating devices. In most homes, geysers are used to generate hot water for domestic use. In many cases, a geyser consumes more electricity than any other device used in a home. The electrical consumption of a geyser in a home can constitute as much as between about 40% to 60% of the total electrical consumption of the home.

Various factors can influence the efficiency of a geyser. For example, scale build up around a heating element of the geyser, deterioration of the heating element, leakage of hot water pipes, leakage of a hot water cylinder of the geyser, leakage of valves on the geyser, failure of a thermostat of the geyser leading to over heating, and the like. In such cases, the geyser typically consumes a greater amount of electricity than would otherwise be the case. In extreme cases, a geyser can consume as much as 500% more electricity than normal. In many cases, a hot water cylinder of a geyser is not protected against earth leakage. Accordingly, various parts of a geyser can deteriorate over time causing excessive electrical consumption without a user of the geyser being aware of such excessive electrical consumption. Eventually, the geyser can fail in a number of ways. For example, a heating element resistance wire of the geyser can suddenly fail thereby disabling the geyser from being able to provide hot water. Instead, the heating element resistance wire of the geyser can suddenly fail in a manner to cause water in the hot water cylinder to close a resistance path and to act as a conductor. In such a case, the water in the hot water cylinder may still be heated, but not enough to reach a preset geyser water temperature. Due to the preset water temperature not being reached, this can cause the heating element to operate continually while heating the water sufficiently for domestic use but without reaching the preset temperature and without the user being aware of the continual operation of the heating element. This can cause the electrical consumption of the geyser to be 400% more than normal.

A thermostat of the geyser can suddenly fail thereby disabling the geyser from being able to provide hot water. An outer sleeve of the heating element can become deteriorated thereby causing heating of water in the hot water cylinder to become very inefficient. It has been found that such deterioration can cause electrical consumption to be up to 800% more than normal.

In many cases, a geyser is situated at a location, such as within a roof of a house, or the like, where the user cannot readily inspect the geyser. Accordingly, the electrical consumption of the geyser can be excessive, while the user is oblivious to such excessive electrical consumption.

It is an object of the invention to provide a geyser control system arranged to permit a user of the geyser to monitor operational parameters of the geyser.

SUMMARY OF THE INVENTION: According to one aspect of the invention, there is provided a method of regulating heating of a heating device, the method including monitoring pre-determined parameters associated with heating of the heating device and interrupting electrical current supply to a heating element of the heating device should any one of the monitored parameters deviate from a pre-determined amount.

Monitoring pre-determined parameters associated with heating of the heating device may include monitoring a heating rate of a liquid being heated by the heating device.

Interrupting electrical current supply to the heating element of the heating device should any one of the monitored parameters deviate from a pre-determined amount may include interrupting the electrical current supply to the heating element should the heating rate be lower than a pre-determined amount.

Interrupting the electrical current supply to the heating element should the heating rate be lower than a pre-determined amount may include interrupting the electrical current supply to the heating element should the heating rate be lower than about 10°C per hour.

Interrupting the electrical current supply to the heating element should the heating rate be lower than a pre-determined amount may include interrupting the electrical current supply to the heating element should the heating rate be lower than about 15°C per hour.

Interrupting the electrical current supply to the heating element should the heating rate be lower than a pre-determined amount may include interrupting the electrical current supply to the heating element should the heating rate be lower than about 20° C per hour. Interrupting electrical current supply to the heating element of the heating device should any one of the monitored parameters deviate from a pre-determined amount may include interrupting the electrical current supply to the heating element should the heating rate be higher than a pre-determined amount.

Interrupting the electrical current supply to the heating element should the heating rate be higher than a pre-determined amount may include interrupting the electrical current supply to the heating element should the heating rate be higher than about 30°C per hour.

Interrupting the electrical current supply to the heating element should the heating rate be higher than a pre-determined amount may include interrupting the electrical current supply to the heating element should the heating rate be higher than about 40°C per hour.

Interrupting the electrical current supply to the heating element should the heating rate be higher than a pre-determined amount may include interrupting the electrical current supply to the heating element should the heating rate be higher than about 50°C per hour.

Monitoring pre-determined parameters associated with heating of the heating device may include monitoring a temperature of the liquid being heated by the heating device.

Interrupting electrical current supply to the heating element of the heating device should any one of the monitored parameters deviate from a pre-determined amount may include interrupting the electrical current supply to the heating element should the temperature of the liquid being heated by the heating device exceed a pre-determined amount. Interrupting the electrical current supply to the heating element should the temperature of the liquid being heated by the heating device exceed a pre-determined amount may include interrupting the electrical current supply to the heating element should the temperature of the liquid being heated by the heating device exceed about 75⁰C.

Interrupting the electrical current supply to the heating element should the temperature of the liquid being heated by the heating device exceed a pre-determined amount may include interrupting the electrical current supply to the heating element should the temperature of the liquid being heated by the heating device exceed about

80⁰C.

85°C.

Monitoring pre-determined parameters associated with heating of the heating device may include monitoring electrical current supply to the heating element of the heating device.

Interrupting electrical current supply to the heating element of the heating device should any one of the monitored parameters deviate from a pre-determined amount may include interrupting the electrical current supply to the heating element should there be an earth leakage.

Monitoring pre-determined parameters associated with heating of the heating device may include monitoring a temperature sensor arranged to measure the temperature of the liquid being heated by the heating device. Interrupting electrical current supply to the heating element of the heating device should any one of the monitored parameters deviate from a pre-determined amount may include interrupting the electrical current supply to the heating element should the temperature sensor fail.

According to another aspect of the invention, there is provided a heating device control system including a temperature sensor arranged to measure a temperature of a liquid when heated by a heating device, a control arrangement arranged to monitor predetermined parameters associated with heating of the heating device and to interrupt electrical current supply to a heating element of the heating device should any one of the monitored parameters deviate from a pre-determined amount and a remote indication device operatively associated with the control arrangement and arranged to indicate to a user that electrical current supply to the heating element of the heating device has been interrupted.

The remote indication device may be arranged to indicate to the user a nature of a fault, which has given rise to the interruption of electrical current supply to the heating element.

The remote indication device may be arranged to indicate to the user that the nature of the fault is that a temperature of the liquid being heated by the heating device has risen higher than a pre-determined amount.

The remote indication device may be arranged to indicate to the user that the nature of the fault is that a heating rate of the liquid being heated by the heating device is higher than a pre-determined amount.

The remote indication device may be arranged to indicate to the user that the nature of the fault is that a heating rate of the liquid being heated by the heating device is lower than a pre-determined amount. The remote indication device may be arranged to indicate to the user that the nature of the fault is an earth leakage.

The remote indication device may be arranged to indicate to the user that the nature of the fault is that the temperature sensor has failed.

According to another aspect of the invention, there is provided a heating device including a control system as described above.

According to another aspect of the invention, there is provided a method of regulating heating of a heating device, the method including monitoring a temperature of a liquid in a heating device, receiving a signal to interrupt electrical current supply to a heating element of the heating device and interrupting electrical current supply to the heating element of the heating device should the monitored temperature of the liquid be higher than a pre-determined amount and maintaining electrical current supply to the heating element of the heating device should the monitored temperature be below the predetermined amount.

The method may include interrupting electrical current supply to the heating element of the heating device should the monitored temperature of the liquid become higher than the pre-determined amount after receipt of the signal to interrupt electrical power supply to the heating element of the heating device.

The pre-determined amount may be in the range of between about 4O⁰C and about 60°C. The pre-determined amount may be in the range of between about 45°C and about 55⁰C. The pre-determined amount may be about 50°C.

According to another aspect of the invention, there is provided a heating device control system including monitoring means arranged to monitor a temperature of a liquid in a heating device, signal receiving means arranged to receive a signal to interrupt electrical current supply to a heating element of the heating device and interruption means arranged to interrupt electrical current supply to the heating element of the heating device should the monitored temperature of the liquid be higher than a pre-determined amount and to maintain electrical current supply to the heating element of the heating device should the monitored temperature be below the pre-determined amount.

The interruption means may be arranged to interrupt electrical current supply to the heating element of the heating device should the monitored temperature of the liquid become higher than the pre-determined amount after receipt of the signal to interrupt electrical power supply to the heating element of the heating device.

The pre-determined amount may be in the range of between about 40°C and 60°C. The pre-determined amount may be in the range of between about 45⁰C and 55⁰C. The pre-determined amount may be about 50⁰C.

According to another aspect of the invention, there is provided a heating device including a control system as described immediately above.

BRIEF DESCRIPTION OF THE DRAWINGS:

Embodiments of the invention, will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which:

Figure 1 shows a schematic diagram of a heating device control system, in accordance with one aspect of the invention;

Figure 2 shows, at an enlarged scale, a schematic view of a remote control device of the heating device control system shown in Figure 1;

Figure 3 shows a schematic circuit diagram of the heating device control system shown in Figure 1 ; Figure 4 shows, at an enlarged scale, a schematic circuit diagram of a remote control device of the heating device control system shown in Figure 3; and

Figure 5 shows, at an enlarged scale, a schematic circuit diagram of a control box of the heating device control system shown in Figure 3.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS:

Referring to Figures 1 and 2 of the drawings, a heating device control system for controlling heating of a heating device, such as a hot water cylinder 12 of a geyser, or the like, for example, is generally indicated by reference numeral 10.

The heating device control system 10 includes a control box, schematically indicated at 14, and a remote indication, or control, device 16. The control box 14 can be positioned in close proximity to the hot water cylinder 12. The remote indication device 16 can be positioned at any convenient location remote from the geyser 12, where the remote indication device 16 is readily accessible by a user, such as, within a room of a house, or the like, for example.

A temperature probe, or sensor, as indicated in dashed lines by reference numeral

21 is typically positioned on the hot water cylinder 12 to measure a temperature of a liquid, such as water, for example, in the hot water cylinder 12. The temperature probe 21 can be in the form of, for example, a PT 100 temperature probe, or the like. The temperature probe 21 is operatively connected to the control box 14 by lines 12.1, 12.2. Monitoring means, generally indicated by reference numeral 23, in the control box 14, is operatively associated with the temperature sensor 21 through lines 12.1, 12.2. The monitoring means 13 is arranged to determine a temperature and a heating rate of the water in the hot water cylinder 12.

The remote indication device 16 includes an on/off button 18, a digital display 20, a timer button 22, a setting button 24, a heating/standby indicator 26, an on/off indicator 28 and a timer indicator 30. The indicators, 26, 28, 30 are typically in the form of LED's (Light Emitting Diodes). By means of the on/off button 18, a user can cause electrical current supply, or power, to a heating element 25 of the hot water cylinder 12 to be switched selectively on or off. Electrical current supply is provided to the heating element 25 through lines 27.1 and 27.2 extending from the control box 14 to the heating element 25. In the case where the user is going to be away for an extended period, the user can use the button 18 to switch off electrical power supply to the hot water cylinder 12 while he, or she, is away, thereby to save on electrical consumption. The button 18 can then be used to switch on electrical current supply to the hot water cylinder 12 when the user returns .

When electrical current supply is supplied to the heating element 25 of the hot water cylinder 12, the indicator 28 is typically on and generates a distinctively coloured light, such as, a red coloured light, for example. When electrical current supply to the heating element 25 of the hot water cylinder 12 is interrupted, the indicator 28 is typically on and generates a distinctively coloured light, such as, a green coloured light, for example. Instead, the indicator 28 can be switched off when electrical current supply to the heating element 25 of the hot water cylinder 12 is switched off. The indicator 26 is typically on to generate a distinctively coloured light, such as a red coloured light, or the like, for example, so as to indicate that the heating element 25 of the hot water cylinder 12 is on and busy heating water in the hot water cylinder 12 to a desired set temperature. When the heating element 25 is switched off, such as, when a set water temperature in the hot water cylinder 12 has been reached, the indicator 26 typically changes to generate a distinctively coloured light, such as a green coloured light, for example, to indicate that water in the hot water cylinder 12 is at a set temperature.

The setting button 24 is typically used to set a desired temperature to which water in the hot water cylinder 12 is to be heated. The display 20 normally displays a temperature of water in the hot water cylinder 12 as measured by the temperature sensor 21. When the setting button 24 is pressed and released, the display 20 typically shows a set temperature in a flashing fashion. To adjust the set temperature, the button 24 is pressed repeatedly until a new desired set temperature is displayed on the display 20. As the button 24 is pressed repeatedly, the temperature displayed on the display 20 typically increases incrementally, such as in steps of 5°C, or the like, for example, between a range of between about 30⁰C to about 85°C, for example. When 85⁰C is reached, the display returns to 30⁰C. In this way, a user can select a desired temperature to which water in the hot water cylinder 12 is to be heated by pressing the button 24 until the desired temperature is displayed on the display 20. After a pre-determined length of time after the button 24 has been released, such as 8 seconds, or the like, for example, the display 20 switches automatically to again display the measured temperature of the water in the hot water cylinder 12.

The system 10 is provided with a timer to enable a user to cause electrical current supply to be supplied to the heating element 25 of the hot water cylinder 12 at a set time in the future. By making use of the timer, a user can switch off electrical current supply to the hot water cylinder 12 and cause electrical current supply to be resumed at a time in the future. For example, if a user is going to be away for a relatively long period of time, electrical current supply can be switched off and the timer can be used to cause electrical current supply to be resumed automatically shortly before the user's return. In this way, electrical consumption can be conserved.

To operate the timer, the button 18 is pressed to switch off electrical current supply to the heating element 25 of the hot water cylinder 12. The timer button 22 is then pressed and a time is then displayed on the display 20 in a flashing fashion. The button 22 can then be pressed repeatedly to increase the time displayed on the display 20. When the button 22 is pressed after three seconds, the displayed time is decreased. If the button 22 is released, the time on the display 20 will be set after a predetermined length of time, such as, 8 seconds, or the like. The measured temperature of the water in the hot water cylinder 12 is then again displayed on the display 20. In this way, the user can cause electrical power to the heating element 25 of the hot water cylinder 12 to be cut and to resume after a predetermined length of time. To see how much of the set time on the timer is left, the timer button 22 is typically pressed once. The remainder of the set time on the timer is then displayed on the display 20. After a predetermined length of time, such as, 8 seconds, or the like, for example, the display 20 again displays the measured temperature of the water in the hot water cylinder 12. After the set time on the timer has lapsed, the normal operation of the hot water cylinder 12 is resumed automatically.

To cancel the timer before the set time has lapsed, the on/off button 18 is pressed once, thereby to cause normal operation of the hot water cylinder 12 to resume. When the system 10 operates under the timer, the indicator 30 is typically switched on to generate a distinctively coloured light, such as yellow coloured light, or the like, for example. The timer can make provision for a time period of between 1 to 99 hours, for example.

The system 10 makes provision for operative association with a domestic load control device. Such a domestic load control device can be in the form of, what is colloquially referred to as, a ripple receiver, or a radio receiver, or the like. Signal receiving means, in the form of a domestic load control device, or ripple receiver, is shown in Figure 1 of the drawings as indicated by reference numeral 15. The signal receiving means, or ripple receiver 15, is arranged to receive a signal to interrupt electrical current supply to the heating element 25 of the heating device 12. It is envisaged that in view of increasing electrical power demands, that a system will be implemented where a governing authority, such as a municipality, or an electrical power supply company, or the like, can cause such domestic load control devices to be installed in homes so that electrical power to hot water cylinders can be cut during peak electrical power demand periods. This can be achieved by a ripple signal through electrical lines 17, 19 supplying electrical current to the heating element 25 of the hot water cylinder 12, or by means of a radio transmitter/receiver arrangement, or the like.

However, should the electrical current to the heating element 25 of the hot water cylinder 12 be cut shortly after the hot water cylinder 12 has been emptied of hot water, this could inconvenience consumers, since hot water would then only become available after the domestic load control device has again been switched. The system 10 provides a solution to such a problem, as will now be described.

When a signal is received by the domestic load control device 15, the display 20 displays an associated message such as, LC, for example, to indicate to a consumer, or user, or the like, that load control is being applied. The signal from the ripple receiver 15 is communicated to the control box 14 through lines 15.1, 15.2, 15.3. Through line 15.1 an "on" signal is selectively passed, through line 15.2 a 12V DC current is selectively passed and through line 15.3 an "off signal is selectively passed. While such load control is being applied, the system 10 is arranged to inhibit the changing of any set parameters on the system 10 by the user. The system 10 includes interruption means, generally indicated by reference numeral 27, arranged to interrupt electrical current supply to the heating element 25 of the heating device 12 should the temperature of the water, as monitored by the monitoring means 23, be higher than a pre-determined amount and to maintain electrical current supply to the heating element 25 of the heating device 12 should the temperature, as monitored by the monitoring means 23, be below the predetermined amount. Accordingly, should the water temperature in the hot water cylinder 12 be less than a predetermined temperature, such as, a specific temperature, or amount, falling in the range of between about 40°C and about 60⁰C, preferably a specific amount falling in the range between about 45°C and about 55⁰C and advantageously an amount of about 50⁰C, or the like, for example, when load control is applied, the signal is typically acknowledged. However, electrical current to the heating element 25 of the hot water cylinder 12 is retained until the specific amount, such as 50°C, for example, is reached. Accordingly, when 51⁰C is reached, for example, electrical current supply to the heating element 25 of the hot water cylinder 12 is then cut.

Should the display LC last too long, then the consumer can recognize that a failure to receive an "on" signal can have occurred and can then report such failure to the relevant authorities. Referring now to Figure 3 of the drawings, where like reference numerals have been used to designate similar parts, unless otherwise stated, a control arrangement, or circuitry, of the control system 10 in the control box 14 and in the remote indication device 16, is generally indicated by reference numeral 29, and will now be described in greater detail.

The control arrangement 29 is arranged to monitor pre-determined parameters, such as a temperature, a heating rate, and the like, associated with heating of the heating device 12 and to interrupt electrical current supply to the heating element 25 of the heating device 12 should any one of the monitored parameters deviate from a predetermined amount. The remote indication device 16 is operatively associated with the control circuitry 29 and is arranged to indicate to a user that electrical current supply to the heating element 25 of the heating device 12 has been interrupted.

Reference numeral 32 indicates a controller section in the form of a MCU (Micro

Control Unit). The controller 32 can typically be similar to an MCU available from TOSHIBA™ under the part number TMP86C807. This can be a relatively high speed and a relatively high performance 8-bit single chip microcomputer having a relatively small package. The MCU can typically include a CPU (Central Processing Unit) core, ROM (Read Only Memory) of 4 kbytes, or 8 kbytes, RAM (Ready Access Memory) of 256 bytes, a multi-role timer counter, SEI (Serial Expansion Interface) and UART (Asynchronous Serial Interface), 8-bit AD converter and two clock generators on the associated chip, for example.

Reference numeral 34 indicates a power supply section. The power supply section 34 can typically include an input for a voltage of AC 230V +/- 10%, a step down by transformer, rectified to provide stable 5 V DC for supplying an appropriate voltage to the MCU. The input voltage can be filtered and can include a Varistor, so as to regulate voltage within an appropriate range and to protect against surge interference. The circuitry sections can typically be such as to comply with specific requirements, such as EMC requirements, or the like. Reference numeral 36 indicates a heating element section. The heating element section 36 can use a double throw control method to control AC Live and Neutral, for safety reasons, and the like. The section 36 can use relays, such as OEG PCF-I l 2DIM relays having a contact rating of 20A 250V maximum, for example. Use can be made of a contact current of up to 25A and a coil rating of 12V DC. The section 36 can be such as to comply with standards recommended by recognized test institutions, such as UL, CSA and TUV, for example. A relay for neutral is indicated at 36.1 and a relay for live is indicated at 36.2. The relays 36.1, 36.2 can be normally open.

Reference numeral 38 indicates an indication section. The indication section 38 can apply scanning methodology to reduce controller consumption. The indication section 38 is arranged to cause a measured temperature of the water in the hot water cylinder 12 normally to be displayed on the display 20. The indication section 38 is arranged to cause a time set on a timer of the system 10 to be displayed selectively on the display 20 and to cause error codes to be displayed selectively on the display 20 when certain mal-functions, or events, occur, as described in greater detail below. The indication section 38 is operatively associated with the remote control device 16 to cause information, such as, power on/off, keep warm/heating, timer activation, and the like, for example, to be indicated on the remote indication device 16. The temperature probe, or sensor, of the control system 10, is indicated at 21. The temperature probe 21 can be in the form of, for example, a PT 100 temperature probe, or the like.

Reference numeral 42 indicates a leakage current section. The leakage current section 42 can apply specific leakage detector circuitry, which can match with a precision current transformer, to safely and accurately detect system leakage current. An associated board of the leakage current section is provided with terminals for checking of leakage current measurement. This enables relative ease of maintenance to enhance system safety. Reference numeral 44 indicates a domestic load control section in the form of a ripple receiver control section. The ripple receiver control section 44 makes provision for operation with a ripple receiver. The heating element 25 of the hot water cylinder 12 can be arranged to operate through a ripple receiver so that when a signal is received from the ripple receiver, the heating element 25 of the hot water cylinder 12 can be caused to be switched on or off under load control. The circuitry for applying such load control can use an opto-coupler isolation method so as to enable the ripple receiver to function independently. Firmware and hardware can typically include filtering to enhance signal interpretation. Signal input from the ripple receiver is indicated generally at 44.1. When load control by the ripple receiver is applied, such load control is displayed on the display 20 through the lines 44.2.

Power supply to the ripple receiver is generally indicated at 45. The power supply 45 can typically be a 220V/230V power supply.

Reference numeral 46 indicates an EEPROM (Electronically Erasable Programmable Read Only Memory) section for storing settings, and the like, in the event of a power outage, or the like. The EEPROM section 46 can apply EEPROM ICs in the event of an electrical power supply interruption, such as when the electrical power is switched off, or in the event of an electrical power supply interruption, or outage, or the like. The EEPROM typically stores settings, such as, timer settings, temperature settings, and the like, for example, and previous modes, such as, on/off status, heating/keep warm status, timer status, ripple receiver (LC) on/off status, and the like, for example, in a memory. The EEPROM IC can typically be an ATMEL 24C0 IA and can have serial EEPROM features, lower power CMOS technology, can be 12C compatible, can have 1000000 Erase/write cycles and a data retention of greater than 200 years, for example.

Reference numeral 48 indicates a display driver for driving the display 20 and is operatively connected at 50. The system 10 provides for an earth fault current, for example, of 17 to 25mA at an action time of less than, or equal to, 0.15 seconds, or the like. The system 10 further provides for overheating, typically at a temperature of greater than about 75 °C, or about 80°, preferably about 85°C. The system 10 also provides for indication of failure of the temperature sensor 21. The system 10 further provides for monitoring a temperature increase, or heating rate. The system 10 can be arranged to determine when the temperature increase, or heating rate, is less than about 10°C per hour and more than about 5°C per 15 minutes, for example.

The control system 10 is typically provided with bi-polar relays so as to enable the heating element 25 of the hot water cylinder 12 to be isolated from the supply of both live and neutral, when any one of a number of predetermined events, or faults, arise. These events include when the on/off button 18 on the remote control device 16 is activated. In such a case an appropriate signal is passed through the line 54.1. When power is supplied, the indicator 28 is coloured red, and when power is interrupted, the indicator 28 is coloured green. The remote indication device 16 is arranged to indicate to a user a nature of a fault, which has given rise to the interruption of electrical current supply to the heating element 25. In the event of an earth leakage, for example, an associated error code, such as "El", is displayed on the display 20 of the remote indication device 16 and an alarm, or beeper, is activated. In such a case an appropriate signal is passed through the line 54.2 and an appropriate signal for activation of the buzzer, or beeper, is passed through the line 54.3. The alarm, or beeper, can be in the form of, for example, a 2 Hz alarm, or the like, as indicated at 52 in Figure 3 of the drawings.

In the event of a heating rate, or temperature increase, of more than a predetermined amount of about 30°C per hour, or about 40°C per hour, or about 50°C per hour, preferably about 5°C per 15 minutes, for example, an associated error code, such as "E2", is displayed on the display 20 of the remote indication device 16 and the alarm 52 is activated. This can be the case where an attempt is made to heat while the hot water cylinder 12 is empty. In the event of a heating rate, or temperature increase, of less than a pre-determined amount of about 10°C per hour, or about 15⁰C per hour, or about 20°C per hour, for example, an associated error code, such as "E4", is displayed on the display 20 of the remote control device 16 and the alarm 52 is activated. This can be the case where the heating element 25 of the hot water cylinder 12 has failed, or due to excessive scale build up on the heating element 25, or due to leakage from an associated hot water pipe, or due to leakage from an associated valve, or the like.

In the event of the temperature sensor, or probe, at 21 failing, for example, an associated error code, such as "E3", is displayed on the display 20 of the remote indication device 16 and the alarm 52 is activated. In such a case an appropriate signal is passed through the line 54.4.

In the event of over heating, such as a temperature of above about 75⁰C, or about 8O⁰C, preferably about 85°C, for example, an associated error code, such as "E5", is displayed on the display 20 of the remote indication device 16 and the alarm 52 is activated.

Typically, as a result of any one of the above events, the relays will be switched to isolate electrical current supply to the heating element 25 of the hot water cylinder 12. This typically includes opening live and neutral lines to the heating element 25 of the hot water cylinder 12. Line 54.5 is an earth line.

The display 20 is typically a two digit digital display. The display 20 can be arranged to generate a high light green colour, for example. The display can be a 16 X 20 display. The display 20 can be arranged normally to display the temperature of the water in the hot water cylinder 12 whether electrical current supply to the heating element 25 is switched on or off. The temperature displayed on the display 20 is typically overridden in the case of one of the events, or faults, as described above and one of the error codes El to E5 is then displayed on the display 20. Conveniently, a table indicating the meaning of the error codes can be provided. The table can be mounted on the remote control device 16. The table can be mounted on a rear surface (not shown) of the device 16.

By means of the button 24 on the remote indication device 16, the temperature to which water is to be heated can be adjusted. When the button 24 is pressed, the display

20 displays the current set temperature in the hot water cylinder 12. By means of the button 22 on the remote indication device 16, the system 10 can cause the water in the hot water cylinder 12 to be heated for a selected time period. After the button 22 is pressed, the display 20 displays a time. The time can be adjusted so as to activate the heating element 25 of the hot water cylinder 12 for an adjusted, or selected, time period.

Claims

CLAIMS:

1. A method of regulating heating of a heating device, the method including: monitoring pre-determined parameters associated with heating of the heating device; and interrupting electrical current supply to a heating element of the heating device should any one of the monitored parameters deviate from a pre-determined amount.

2. A method of regulating heating of a heating device as claimed in claim 1, in which monitoring pre-determined parameters associated with heating of the heating device includes monitoring a heating rate of a liquid being heated by the heating device.

3. A method of regulating heating of a heating device as claimed in claim 2, in which interrupting electrical current supply to the heating element of the heating device should any one of the monitored parameters deviate from a pre-determined amount includes interrupting the electrical current supply to the heating element should the heating rate be lower than a pre-determined amount.

4. A method of regulating heating of a heating device as claimed in claim 3, in which interrupting the electrical current supply to the heating element should the heating rate be lower than a pre-determined amount includes interrupting the electrical current supply to the heating element should the heating rate be lower than about 10°C per hour.

5. A method of regulating heating of a heating device as claimed in claim 3, in which interrupting the electrical current supply to the heating element should the heating rate be lower than a pre-determined amount includes interrupting the electrical current supply to the heating element should the heating rate be lower than about 15°C per hour.

6. A method of regulating heating of a heating device as claimed in claim 3, in which interrupting the electrical current supply to the heating element should the heating rate be lower than a pre-determined amount includes interrupting the electrical current supply to the heating element should the heating rate be lower than about 20⁰C per hour.

7. A method of regulating heating of a heating device as claimed in any one of claims 2 to 6 inclusive, in which interrupting electrical current supply to the heating element of the heating device should any one of the monitored parameters deviate from a pre-determined amount includes interrupting the electrical current supply to the heating element should the heating rate be higher than a pre-determined amount.

8. A method of regulating heating of a heating device as claimed in claim 7, in which interrupting the electrical current supply to the heating element should the heating rate be higher than a pre-determined amount includes interrupting the electrical current supply to the heating element should the heating rate be higher than about 30⁰C per hour.

9. A method of regulating heating of a heating device as claimed in claim 7, in which interrupting the electrical current supply to the heating element should the heating rate be higher than a pre-determined amount includes interrupting the electrical current supply to the heating element should the heating rate be higher than about 4O⁰C per hour.

10. A method of regulating heating of a heating device as claimed in claim 7, in which interrupting the electrical current supply to the heating element should the heating rate be higher than a pre-determined amount includes interrupting the electrical current supply to the heating element should the heating rate be higher than about 50⁰C per hour.

11. A method of regulating heating of a heating device as claimed in any one of claims 2 to 10 inclusive, in which monitoring pre-determined parameters associated with heating of the heating device includes monitoring a temperature of the liquid being heated by the heating device.

12. A method of regulating heating of a heating device as claimed in claim 11, in which interrupting electrical current supply to the heating element of the heating device should any one of the monitored parameters deviate from a pre-determined amount includes interrupting the electrical current supply to the heating element should the temperature of the liquid being heated by the heating device exceed a pre-determined amount.

13. A method of regulating heating of a heating device as claimed in claim 12, in which interrupting the electrical current supply to the heating element should the temperature of the liquid being heated by the heating device exceed a pre-determined amount includes interrupting the electrical current supply to the heating element should the temperature of the liquid being heated by the heating device exceed about 75°C.

14. A method of regulating heating of a heating device as claimed in claim 12, in which interrupting the electrical current supply to the heating element should the temperature of the liquid being heated by the heating device exceed a pre-determined amount includes interrupting the electrical current supply to the heating element should the temperature of the liquid being heated by the heating device exceed about 80°C.

15. A method of regulating heating of a heating device as claimed in claim 12, in which interrupting the electrical current supply to the heating element should the temperature of the liquid being heated by the heating device exceed a pre-determined amount includes interrupting the electrical current supply to the heating element should the temperature of the liquid being heated by the heating device exceed about 85°C.

16. A method of regulating heating of a heating device as claimed in any one of the preceding claims, in which monitoring pre-determined parameters associated with heating of the heating device includes monitoring electrical current supply to the heating element of the heating device.

17. A method of regulating heating of a heating device as claimed in any one of the preceding claims, in which interrupting electrical current supply to the heating element of the heating device should any one of the monitored parameters deviate from a predetermined amount includes interrupting the electrical current supply to the heating element should there be an earth leakage.

18. A method of regulating heating of a heating device as claimed in any one of the preceding claims, in which monitoring pre-determined parameters associated with heating of the heating device includes monitoring a temperature sensor arranged to measure the temperature of the liquid being heated by the heating device.

19. A method of regulating heating of a heating device as claimed in claim 18, in which interrupting electrical current supply to the heating element of the heating device should any one of the monitored parameters deviate from a pre-determined amount includes interrupting the electrical current supply to the heating element should the temperature sensor fail.

20. A heating device control system including: a temperature sensor arranged to measure a temperature of a liquid when heated by a heating device; a control arrangement arranged to monitor pre-determined parameters associated with heating of the heating device and to interrupt electrical current supply to a heating element of the heating device should any one of the monitored parameters deviate from a pre-determined amount; and a remote indication device operatively associated with the control arrangement and arranged to indicate to a user that electrical current supply to the heating element of the heating device has been interrupted.

21. A heating device control system as claimed in claim 20, in which the remote indication device is arranged to indicate to the user a nature of a fault which has given rise to the interruption of electrical current supply to the heating element.

22. A heating device control system as claimed in claim 21, in which the remote indication device is arranged to indicate to the user that the nature of the fault is that a temperature of the liquid being heated by the heating device has risen higher than a pre- determined amount.

23. A heating device control system as claimed in claim 21 or claim 22, in which the remote indication device is arranged to indicate to the user that the nature of the fault is that a heating rate of the liquid being heated by the heating device is higher than a pre- determined amount.

24. A heating device control system as claimed in any one of claims 21 to 23 inclusive, in which the remote indication device is arranged to indicate to the user that the nature of the fault is that a heating rate of the liquid being heated by the heating device is lower than a pre-determined amount.

25. A heating device control system as claimed in any one of claims 21 to 24 inclusive, in which the remote indication device is arranged to indicate to the user that the nature of the fault is an earth leakage.

26. A heating device control system as claimed in any one of claims 21 to 25 inclusive, in which the remote indication device is arranged to indicate to the user that the nature of the fault is that the temperature sensor has failed.

27. A heating device including a control system as claimed in any one of claims 20 to 26 inclusive.

28. A method of regulating heating of a heating device, the method including: monitoring a temperature of a liquid in a heating device; receiving a signal to interrupt electrical current supply to a heating element of the heating device; and interrupting electrical current supply to the heating element of the heating device should the monitored temperature of the liquid be higher than a pre-determined amount and maintaining electrical current supply to the heating element of the heating device should the monitored temperature be below the pre-determined amount.

29. A method of regulating heating of a heating device as claimed in claim 28, which includes interrupting electrical current supply to the heating element of the heating device should the monitored temperature of the liquid become higher than the pre-determined amount after receipt of the signal to interrupt electrical power supply to the heating element of the heating device.

30. A method of regulating heating of a heating device as claimed in claim 28 or claim 29, in which the pre-determined amount is in the range of between about 4O⁰C and about 60°C.

31. A method of regulating heating of a heating device as claimed in claim 28 or claim 29, in which the pre-determined amount is in the range of between about 45 °C and about 55°C.

32. A method of regulating heating of a heating device as claimed in claim 28 or claim 29, in which the pre-determined amount is about 50°C.

33. A heating device control system including: monitoring means arranged to monitor a temperature of a liquid in a heating device; signal receiving means arranged to receive a signal to interrupt electrical power supply to a heating element of the heating device; and interruption means arranged to interrupt electrical current supply to the heating element of the heating device should the monitored temperature of the liquid be higher than a pre-determined amount and to maintain electrical current supply to the heating element of the heating device should the monitored temperature be below the predetermined amount.

34. A heating device control system as claimed in claim 33, in which the interruption means is arranged to interrupt electrical current supply to the heating element of the heating device should the monitored temperature of the liquid become higher than the pre-determined amount after receipt of the signal to interrupt electrical power supply to the heating element of the heating device.

35. A heating device control system as claimed in claim 33 or claim 34, in which the pre-determined amount is in the range of between about 4O⁰C and 60°C.

36. A heating device control system as claimed in claim 33 or claim 34, in which the pre-determined amount is in the range of between about 45⁰C and 55°C.

37. A heating device control system as claimed in claim 33 or claim 34, in which the pre-determined amount is about 50⁰C.

38. A heating device including a control system as claimed in any one of claims 33 to 37 inclusive.