Water heating systems




Water heating systems - overview

Choosing the method by which hot water is supplied is often pre-determined by the choice of central heating system; which is ironic as heating systems in the UK are used on average for less than five months of the year. In addition the amount of heating required can be pre-determined, i.e. 18 degrees centigrade in the bedrooms, 21 degrees in the living room and so on. It is the hot water requirement that tends to vary with usage, yet it is often treated as a lower requirement to, boiler location, ease of installation, cost etc. The issue is often compounded by the variety and choice of water heating systems that are now available, yet in general terms there are only two main types of system:

Instantaneous water heating which heats water as required Hot water storage, which stores hot water ready for use

Many would argue that this is an over simplification, and of course there are many derivatives of each. Both hot water systems have different characteristics and some of the key issues for consideration include:

Type of fuel available Number and age of occupants in the dwelling How much hot water do you need Is the water heating system to be a part of the central heating system Number of hot water draw off points, bathrooms en-suit etc Speed of hot water delivery Flow rate requirement Space available for hot water appliances Suitability of location and technical feasibility, flues etc Preference for a dry loft space Cost verses benefits


		The key issue is to specify and install a system that is best matched to your individual needs and circumstances at a cost that you can afford. However care needs to be taken to ensure that the system installed does not adversely affect the value of your property. When purchasing a system the specifier needs to consider the type of property i.e. public building, rented accommodation, personal home dwelling and the long term plans for occupancy i.e. investment property or life long home. A full central heating system is often perceived to add value to a property irrespective of age, yet in a small one bedroom or partially used property instantaneous heaters may be more appropriate. A balance therefore, needs to be obtained, between installation cost, intended usage and investment criteria.

		Any hot water system must be able to meet the requirements of the whole house. That is all sanitary units and whatever appliances are connected e.g. dishwashers, washing machines etc. Bathing tends to create the largest demand for hot water; each bath will require approximately 65 litres of hot water. The size of the property and layout of the rooms that have sanitary fittings also needs consideration. Long pipe runs supplying hot water would probably be un-acceptable for centralized instantaneous heater systems, and a combination of systems may be more appropriate. This section aims to examine the two main types of water heating and their derivatives, giving a simplistic overview of each system so that the reader can gain a holistic view of the choices that are available.





		Instantaneous or hot water storage? The first consideration and decision to make is whether the needs of you, your family, or visitors will be met by an instantaneous or a stored hot water system.


		Choosing a hot water cylinder Quality manager Mike Wilson talks through the varying requirements that need to be considered when choosing a new or replacement hot water cylinder, click on the links below to view details.


		Thermal stores: How they work Heat Banks or thermal stores are advanced hot water storage units, providing high flow rates of mains pressure drinkable hot water. Richard Hanson-Graville, Technical director at DPS Heatbanks, a leading manufacturer and supplier of water heating systems, explains how thermal stores work.


		Direct fired water heaters Direct fired water heaters provide one of the most energy efficient methods of heating water available on the market today. low Cost Operation, consistent reliability of performance can be maintained during daily use with reduced heat recovery times due to the use of efficient burners, and high density boiler insulation which ensures minimum heat loss.


		Components used in mains pressure water storage systems Watts Industries is one of the largest valve manufactures in the world , Managing Director Grant Phipps discusses some of the critical components used in the design and manufacture of mains pressure water storage systems.


		Open vented stored hot water systems With open vented systems a large volume of cold water is stored in a header tank located at a higher level than the cylinder usually in the attic. The water storage cylinder usually located in the airing cupboard is fed at the base of the cylinder by the header tank.


		Mains pressure hot water heating systems Mains pressure stored water systems, in general terms, rely on the water pressure within the mains supply to push the water out of the cylinder, through the pipe circuits to the tap or shower outlet.


		Controlling hot water safely in domestic properties This guide is intended to provide information that will lead to increased levels of both comfort and safety in the UK's 25 million homes. It has been prepared by Members of the Thermostatic Mixing Valve Manufacturers Association (TMVA).


		Scale in water heating systems Most people are familiar with the build up of scale on the elements of kettles and immersion heaters in hard water areas in the country, however, scale formation in closed circuit water heating systems is rarely considered.


		Alternative renewable energy systems Solar systems are not new, and have been used the world over for decades. With over 40,000 systems installed in the UK solar power is becoming the leading source of providing alternative energy. Now is the time for UK plumbers to get to grips with solar technology, and start presenting it as a serious option to customers.