GB2384552A

GB2384552A - A hot water boiler which prevents excess heat build-up

Info

Publication number: GB2384552A
Application number: GB0201553A
Authority: GB
Inventors: Roy Goodwill
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-01-24
Filing date: 2002-01-24
Publication date: 2003-07-30
Also published as: GB0201553D0

Abstract

A central heating system is connected to a heater 9 and a pump 10 wherein the pump operates for longer than the heater. This allows the heater to cool down without an excess of boiling water building up in the heater. The heater and pump may be mounted in, or remotely connected to, a boiler. Initiation of heater and pump is simultaneous. The heater may operate continuously or intermittently while switched on. The pump may operate for 20 to 30 minutes longer than the heater. A thermostat 8 may be provided to sense ambient air temperature. A timer 7 may control the operating periods of the heater and pump. The boiler may have a pump override 6 so that hot water is not circulated.

Description

IMPROVEMENTS IN AND RELATING TO HEATING Field of the Invention This invention relates to methods of circulating hot water round a hot water heating apparatus and to hot water boilers per se.

Background to the Invention Many hot water based heating systems, especially domestic central heating systems, comprise a central heating boiler comprising a boiler heater and a boiler pump, to which is connected a pipe system interspersed with radiator units.

Generally the boiler will be connected to a thermostat which senses the temperature in a given environment, and actuates the heater and pump as and when necessary. When the heater and pump are actuated, water is passed into the heater, heated to the required temperature and then pumped through the pipe and radiator system by the boiler pump, in order to heat up rooms or other enclosed environments in which the radiators are furnished.

When it is desired to allow the rooms or enclosed environments to cool down, such as when the thermostat is timed to switch off, the pump and boiler are simultaneously stopped, and the water within the hot water heating system allowed to cool down until the thermostat actuates the system at the next desired time period.

Generally speaking, the boiler heater comprises a number of heater fins, which heat up and are arranged such that water passes through and around the fins and the water is

heated up by heat transfer from the heater fins. When the boiler and pump are stopped simultaneously, the flow of water through the heater also stops. The heater fins takes some time to cool down, and during this time, the water which has stopped within the heater and which is present around the fins, is continually heated to boiling point. As the water trapped within the heater boils, steam bubbles are formed which causes loud banging and rattling within the heater and water pipe system and can also cause shaking in the pipe system and radiators, which could lead to joints rupturing, and potentially lead to water leaking into a room or other enclosed environment.

In some hot water heating systems, the heater further exacerbates the situation by continually being fired and stopped when the pump has ceased pumping, thereby continually heating the trapped water within the fins to boiling point. Continuous firing and cessation of the heater is especially prevalent in hot water heating systems which also include a hot water storage tank, from which hot water to outlets or taps is provided. The hot water heating system is then usually programmed such that the heater fires periodically, in order to keep the tank of hot water at the required temperature. However, as the boiler pump is not actuated at this time, stationary water is still present within the fins of the boiler heater, and the same problems arise as for the hot water heating system per se. Some existing hot water control systems rectify this problem by employing a hot water thermostat within the hot water tank which stops the heater firing when sufficient hot water is in the tank when the pump is not circulating. In other known hot water systems hot water is fed by the pump through a thermostatically

controlled valve. Both of these systems require additional materials to implement and are difficult or expensive to fit into existing hot water systems.

It would therefore be advantageous to provide a hot water heating apparatus which did not generate steam bubbles or cessation of heating and pumping and which could be retrofitted into existing hot water heating systems, without undue cost or burden.

It is therefore an aim of preferred embodiments of the present invention to overcome or mitigate at least one problem of the prior art, whether expressly disclosed hereinabove, or not.

Summary of the Invention According to the present invention in a first aspect, there is provided a method of circulating hot water round a hot water heating apparatus, the method comprising the steps of: (a) providing a water heater and a water pump connected to a hot water heating apparatus; (b) initiating operation of the water heater and water pump to pump heated water round the heating apparatus; (c) maintaining operation of the heater during a first time period before shutting down the heater; and (d) maintaining operation of the pump during a second time period before shutting down the pump;

wherein the second time period is longer than the first time period, such that the operation of the pump is maintained for a period of time after the heater is shut down.

Suitably the water heater and water pump are mounted together in a hot water boiler. Alternatively one of the water heater and water pump may be remotely connected to the hot water boiler. For example the heater may be mounted in the casing of a hot water boiler, with the water pump mounted in a separate casing.

Suitably, initiation of operation of the water heater and water pump occurs substantially simultaneously.

Step (c) may comprise continuous heating of the water during the first time period, or intermittent heating of the water during the first time period.

Suitably the second time period is between substantially 1 minute longer and 60 minutes longer than the first time period, preferably between substantially 5 minutes and 45 minutes longer, more preferably between substantially 20 minutes and 30 minutes longer, and most preferably substantially 25 minutes longer.

Suitably the heating apparatus is a hot water central heating system, preferably a domestic hot water central heating system, and more preferably a gas-powered domestic hot water central heating system.

Preferably the hot water heating apparatus comprises a temperature sensor operably connected to the heater and

pump, which sensor initiates step (b) of the method upon sensing a minimum prescribed temperature of the air in a substantially enclosed space in which the heating apparatus is mounted.

Thus, the method may be repeated when the temperature sensor senses a drop in temperature to the prescribed minimum after the method has been performed.

Preferably the temperature sensor is a thermostat.

Suitably a timer is provided to operate the heater and pump for the first and second time periods.

According to a second aspect of the present invention there is provided a hot water boiler comprising a water heater and a water pump, operably connected to a control means, wherein the control means, in use, is arranged to initiate operation of the heater for a first prescribed time period before shutting off the heater, and initiate operation of the pump for a second prescribed time period before shutting off the pump, wherein the second time period is longer than the first time period.

Suitably the boiler is connected to a hot water heating apparatus, such as a hot water central heating system, and preferably a domestic central heating system.

Suitably the control means is a temperature sensor, more preferably a thermostat. Preferably the temperature sensor is arranged, in use to sense the temperature of an airspace to be heated.

The control means may be situated remote to the heater and pump, and may be situated in a separate airspace to that in which the boiler is arranged to be situated.

The boiler is preferably provided with a pump shut-off means which in use, is arranged to prevent operation of the pump if desired, in order that the heater may operate to provide hot water which is not circulated by the pump, for example to provide hot tap water only.

According to a third aspect of the present invention there is provided the method of circulating hot water round a hot water heating apparatus of the first aspect of the invention, using the hot water boiler of the second aspect of the invention.

Brief Description of the Drawings For a better understanding of the various aspects of the invention and to show how embodiments of the same may be put into effect, a preferred embodiment of the invention will now be described by reference to the following drawings, in which: Figure 1 is a flow diagram of a system for boiler pump control in a hot water boiler of the invention; and Figure 2A is a graph showing heating and pumping timings using a hot water boiler of the invention having a boiler pump which utilises the flow control of the diagram of Figure 1 to provide both instant hot water and pumped hot water in a central heating system; and

Figure 2B is a graph showing heating timings of using a hot water boiler of the invention which comprises a boiler pump which utilises the flow control diagram of Figure 1, to provide instant hot water only.

Description of the Preferred Embodiment We refer firstly to Figure 1 which illustrates a flow diagram of a boiler pump control system suitable for incorporating into a central heating system containing hot water boiler which comprises a boiler heater and a circulating pump.

The flow diagram can be put into effect by construction of a suitable circuit board easily manufacturable by persons skilled in the art, and which can be retro-fitted into existing hot water boilers.

Referring to Figure 1, a preferred embodiment of a hot water boiler of the invention includes a pump controller 4 which controls operation of both a boiler heater 9 and boiler pump 10. The boiler pump 10 and pump controller 4 are connected to a combined adjustable delay and pump override controller 6. The adjustable delay and override controller 6 is also connected to a boiler controller 2, and a boiler heater 9 which includes a heater thermostat

11. The boiler controller 2 is further connected to a day timer controller 7 which can be set by a user to control heating at a central heating apparatus. The pump controller 4 is also connected to a room thermostat 8

which receives signals from the day time controller 7 or which can be manually operated.

In use signals from the pump controller 4 initiate operation of the pump 10 by switching the pump controller 4 between"on"and"off"states. When the pump controller 4 is in the"on"state, water heated by the boiler heater 9 is pumped round the central heating system by the pump 10. When the pump controller 4 signals the pump to turn off, the delay and override controller 6, set by a user, signals the pump to remain"on"for a period prescribed by the user, before switching the pump 10 off.

The pump controller 4 is not utilised when it is desired to prevent the pump 10 from functioning if it desired to heat water without subsequent pumping.

We refer now to Figures 2A-and 2B. Figure 2A is a graphical representation of on/off timings of a typical room thermostat, central heating boiler pump and boiler heater, utilising a boiler controller system of the flow diagram of Figure 1. Figure 2A also shows the temperature changes induced by use of the central heating boiler.

The room thermostat 7, central heating boiler pump 10 and boiler heater 9 may be any known type suitable for heating and pumping water round a central heating apparatus, as are well known to those skilled in the art.

On a signal from the day timer 7 within the central heating apparatus or by user input, a room thermostat 8, turns on. The pump controller 4 turns on, and both the boiler pump 10 and boiler heater 9 are started

simultaneously, as can be seen from Figure 2A. The thermostat continues to run in the"on"position whilst the temperature remains below 220C (adjustable to suit the user). During the time that the room thermostat is on, the central heating pump 10 continues to circulate water heated by the boiler heater 9. During the time that the thermostat 7 remains on, the boiler heater 9 is arranged to heat hot water passing through the heater 9 at intervals, as shown in Figure 2A, as the boiler heater 9 has its own built in thermostat control 11.

When the room temperature has reached the desired 220C (or other desired temperature depending on the user), the room thermostat 8 signals the pump controller 4, which signals the heater 9 and pump 10 to turn off. The heater 9 is immediately switched off upon receiving the signal from the boiler controller 4, but the pump delay and override controller 6 ensures the pump. 10 continues to run for a user-prescribed time period"A", before switching the pump 10 off as shown in Fig. 2A. Time period"A"may be any desired time, but is suitably around 25 minutes. This extra time period in which the cooling water is circulated prevents steam build up within the boiler heater 9 which may cause banging and/or shaking of the boiler and central heating system.

As the temperature of the room cools down, the thermostat 8 senses the drop in temperature and is arranged to switch on when the temperature drops to a prescribed level, such as 200C as shown in Fig. 2A. The thermostat 8 produces a signal which simultaneously turns on the pump 10 and heater 9 to repeat the above process, and keep the room temperature between 20 and 22 C.

Figure 2B shows a situation in graphical format whereby it is desired to provide instant hot water but not pump hot water round a central heating system, such as during summertime. In this situation, the room thermostat 8 is turned off. The central heating pump 10 is prevented from being turned on by the override function of the pump delay and override 6 which prevents the pump controller 4 from being switched on. The override function of the pump delay and override 6 may be activated by the user when desired, through the boiler controller 2. The boiler heater 9 is turned at intervals on by signals from the boiler controller 2 in order to maintain a constant supply of instant hot water for a user to access through, for example, hot water taps.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same,

equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment (s). The invention extend to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

Claims: 1. A method of circulating hot water round a hot water heating apparatus, the method comprising the steps of: (a) providing a water heater and a water pump connected to a hot water heating apparatus ; (b) initiating operation of the water heater and water pump to pump heated water round the heating apparatus; (c) maintaining operation of the heater during a first time period before shutting down the heater; and (d) maintaining operation of the pump during a second time period before shutting down the pump ; wherein the second time period is longer than the first time period, such that the operation of the pump is maintained for a period of time after the heater is shut down.
2. A method as claimed in Claim 1, wherein the water heater and water pump are mounted together in a hot water boiler.
3. A method as claimed in Claim 1, wherein one of the water heater and water pump is remotely connected to the hot water boiler.
4. A method as claimed in any one of Claims 1 to 3, wherein initiation of operation of the water heater and water pump occurs substantially simultaneously.

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5. A method as claimed in any preceding claim, wherein step (c) comprises continuous heating of the water during the first time period.
6. A method as claimed in any one of Claims 1 to 4, wherein step (c) comprises intermittent heating of the water during the first time period.
7. A method as claimed in any preceding claim, wherein the second time period is between substantially 1 minute longer and 60 minutes longer than the first time period.
8. A method as claimed in Claim 7, wherein the second time period is between substantially 20 minutes longer and substantially 30 minutes longer than the first time period.
9. A method as claimed in any preceding claim, wherein the heating apparatus is a hot water central heating system.
10. A method as claimed in any preceding claim, wherein the hot water heating apparatus comprises a temperature sensor operably connected to the heater and pump, which sensor initiates step (b) of the method upon sensing a minimum prescribed temperature of the air in a substantially enclosed space in which the heating apparatus is mounted.
11. A method as claimed in any preceding claim, wherein a timer is provided to operate the heater and pump for the first and second time periods.

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12. A hot water boiler comprising a water heater and a water pump, operably connected to a control means, wherein the control means, in use, is arranged to initiate operation of the heater for a first prescribed time period before shutting off the heater, and initiate operation of the pump for a second prescribed time period before shutting off the pump, and wherein the second time period is longer than the first time period.
13. A boiler as claimed in Claim 12, connected to a hot water heating apparatus.
14. A boiler as claimed in Claim 12 or 13, wherein the control means is a temperature sensor.
15. A boiler as claimed in Claim 14, wherein the temperature sensor is arranged, in use, to sense the temperature of an airspace to be heated.
16. A boiler as claimed in any one of Claims 12 to 15, wherein the control means is situated remote to the heater and pump.
17. A boiler as claimed in any one of Claims 12 to 16, wherein the boiler is provided with a pump shut off means which in use, is arranged to prevent operation of the pump if desired, in order that the heater may operate to provide hot water which is not circulated by the pump.

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18. A method of circulating hot water round a hot water heating apparatus as claimed in any one of Claims 1 to 11, using the hot water boiler of any one of Claims 12 to 17.
19. A method substantially as described herein with reference to the accompanying drawings.
20. A hot water boiler substantially as described herein with reference to the accompanying drawings.