Trench Heating.

There can be no doubt about it. The modern home is becoming the focus of considerable advances and developments in technology and innovation, all designed to maximise comfort and minimise energy consumption.

The efficient and effective distribution of heat around the home is creating some unique challenges, particularly where the adaptation of an existing system or structure is required. New builds and renovations require much forethought and planning to ensure that an appropriate heating system is installed during the building’s progression to avoid problems and inconveniences at a later date.

Many new-build and renovation projects are seeking to maximise the availability of natural lighting. Modern techniques of glass manufacture can now produce tough, durable and ultra-violet light reducing products that are ideal for creating the effect of a spacious environment and, particularly in a rural setting, allowing the full impact of the external landscape to be enjoyed.

However, floor to ceiling glass that offers such panoramic and light admitting characteristics also exposes the home to a cold, un-insulated surface, where heat loss can be substantial and condensation a major problem.

Installing patio doors or building the extension of a conservatory, an orangery or simply an annex with a large incorporation of glass, or with a limited amount of space, can all lead to similar problems.

The installation of trench heating can provide a convenient and practical solution to these problems and also provide an alternative in situations where the installation of conventional under-floor heating systems might not be feasible or appropriate.

The use of trench heating systems in offices and large open plan buildings has been widespread for many years, but the installation of a domestic modification is slowly becoming a desirable option for home-owners.

As the name suggests, trench heating is usually recessed into the floor of the property, although there are variations of the system that can be semi-recessed or floor level mounted.

The systems can be either fitted with electric heating elements or plumbed into a conventional low-pressure hot water gas or electric boiler installation.

They can also be fuelled by ground or air source heat pumps and other renewable energy sources that supplement the output either entirely or as complimentary energy addition to the boiler output. For large installations, it is possible to install fan-assisted systems.

Trench heating can be installed around the entire perimeter of a room or specifically positioned to combat problems that arise on external walls where glass is used extensively. With fully recessed systems, the groundwork of laying the narrow trench in preparation for installation is best accomplished at an early stage in the build or renovation.

Trench heating can provide the sole heating source for a room or operate as a heat boost for rooms with under-floor heating systems, which are generally slow to respond to changes in ambient temperature.

With a trench heating wet system that has been installed as the primary heating source for a room; the boiler must have sufficient capacity to run the system. Manufacturer’s recommend at least 25% more capacity than a comparable radiator system. Where under-floor heating is also installed, the system should have its own, separate circuit on the boiler system to ensure that flow and return temperatures are high enough to give an efficient heat output.

In a wet system, piped water enters into a mini-radiator laid horizontally along the base of the trench. This mini-radiator is comprised of numerous fins, which are designed to maximise the heat exchange between the cold air and the hot water circulating through the element.

Where glass or cold walls are directly above the trench heating system, air that has come into contact with the cold surface falls into the trench. Here it is heated by the mini-radiator element and rises again. This form of natural convection heating creates a gentle circulatory air flow which operates from the ground upwards, heating the room very effectively. It also creates a curtain or barrier of air between the cold surface and the rest of the room, which is maintained by the cold down-draft and the warm up-draft.

Trench heating systems are very easy to install into pre-prepared trenches. The necessary work and skills are well within the capabilities of a confident DIY enthusiast. However, the system design, the layout plans and the system components are generally compiled by the manufacturer to the customer’s individual specifications. This ensures that when installed, the system will operate in line with expectations. The output will be calculated to operate in the most efficient way by taking into account the energy requirements of the installation environment.

One of the major advantages of a trench heating system is the fact that when it is installed it is unobtrusive. It also operates silently and produces a gentle circulation pattern within a room, avoiding the turbulence and hot spots created by traditional radiators. Humidity levels within the room are also improved and the tendency for condensation to form is removed.

Another interesting feature of the circulation pattern created by trench heating is that dust and allergens, which would generally circulate on air currents within the room, are drawn into the trench by the cold air down-draft and collect. This feature is an advantage for households where members are affected by respiratory conditions and sensitivities such as asthma, although conversely, the accumulated debris will need cleaning from the trench periodically to maintain efficiency. Cleaning is a simple process as access to the trench and fins are achieved by removing or rolling back the flexible grid covering the trench.

The surface grids of a trench heating system may cause a problem for ladies wearing stiletto heels, but whether you would wish to have such pressure concentrating accessories denting your carpets and floor surfaces is a matter of personal preference.

Perhaps the biggest drawback to trench heating is the installation cost. As installation is specific to an individual property and the extent of the installation, the cost will vary, however it is doubtful whether a system could be installed for less than £200 a metre, excluding a boiler installation if this is also required.

Most systems come with a ten-year warranty. They are relatively maintenance free and the home-owner can have the piece of mind that if any failure of the system should occur, access to the area of the fault is an easy procedure, unlike under-floor heating or pipe-work for radiators concealed under floorboards.

In general, domestic installations where glass is a feature such as a barn conversion or conservatories, which can be cold in winter, are likely to benefit the most from a trench heating installation.









Installing a New Boiler and Changing the System from Gravity to Pressurised.



If you have an old gravity fed hot water system and an equally old, inefficient boiler, you may consider upgrading to something a little more modern, reliable and efficient. Perhaps your gravity fed hot water pressure is just too low to meet today’s requirement of instant hot water and the increased demands of the household and water using appliances. Maybe you just feel uncomfortable about having a great volume of stored water literally suspended above your head and the potential for devastating water damage if the tank or supporting structure should fail.

Whatever your reasons, and despite inventive sales pitches and exaggerated claims by pushy salesmen, any decision to replace a gravity fed system with a pressurised one must be taken carefully. By not taking into consideration a number of important factors, an unsuspecting homeowner could end up with a new system that is far less efficient than the one it replaces.

The first thing to consider when confronted with claims made about the benefits and advantages of installing a pressurised system is the existing water pressure and flow rates. Despite elaborate claims to the contrary, performance from a mains pressure maintained system is only as good as the mains pressure and water flow rate that supplies it. Manufacturers and installers may give reassuring and appealing indications of the potential output from a system, but the reality is often quite different.

Always consult with your water provider prior to making the decision to install a mains pressure system. They can supply information relating to water pressure and flow rates supplying your property. If your water provider consistently delivers water at a pressure or flow rate below the levels required by a new mains pressure system, you might be better looking at alternative systems.  It is illegal to fit a water pump to the mains supply in an attempt to increase low water pressure and flow rates.

Where the water provider confirms a suitable pressure and flow rate, it is a good idea to check whether the pressure and flow rates are also adequate within the property. The diameter of the pipe-work from the provider’s communication pipe may be too narrow to maintain an adequate flow rate. Although a new water supply pipe can be installed, it will be the homeowner’s responsibility to shoulder the cost. This is something to bear in mind when costing the installation.

It is also a good precaution to ensure that the gas supply pipe is of an appropriate diameter to provide a new condensing boiler with a sufficient gas flow to operate efficiently. Old gas supply pipes are often narrow and may need replacing. Another potential cost to consider.

If these requirements can be adequately met, you may wish to consider simply installing a combi boiler if that system will supply your requirements.

Alternatively, if you have a large home and a high demand for hot water you might wish to consider a fully pressurised system.  A condensing boiler can provide substantial quantities of hot water and run a heating system all at mains pressure.

However, before embarking on this system, and particularly where old radiators are installed and the intention is to retain them, the system should be pressure checked. This will help to establish, although not guarantee, whether the central heating system can function under increased pressure.

Often, when converting from gravity fed to mains pressure, old pipe-work reveals and succumbs to weaknesses that are not evident under low-pressure conditions. It may be necessary to replace the entire central heating network. This might, of course, be necessary by virtue of its age, condition and inefficiency. Sometimes, adaptations and modifications over the years can produce a central heating system with a tangle of pipe-works of varying diameters and distribution paths that become problematic in relation to efficiency and maintenance. All the same, this possible replacement should be considered as a potential extra cost.

With a totally un-vented mains water pressurised system, it is important to fit a hot water storage cylinder capable of withstanding the high pressure in the system. Under no circumstances should an existing low-pressure copper cylinder be retained and used. High-pressure cylinders are generally made from steel and incorporate specialised pressure releasing safety devices either directly or remotely.

It is possible to install a mains water pressure system that incorporates a vented hot water supply at mains pressure. However, this system uses a process of heat storage and heat exchange to either indirectly or directly heat incoming cold mains water. This preserves the mains pressure but allows for expansion of hot water to be accommodated through an F and E tank, usually situated in the loft. This vented system does not store hot water under pressure and can be viewed as a safer alternative by some households.

Finally, when it comes to installation there are a few important factors to consider which may help a homeowner decide which mains water pressure system to install.

An un-vented mains pressure system will provide hot water at mains pressure to all taps and outlets and does not require any F and E tank or storage tank in the loft. However, it does require a specialised high-pressure storage cylinder and pressure release systems. A specialist engineering company with competent engineers must install an un-vented mains pressure system. The installation must be notified to Building Control at the local council and must be commissioned and certified by a registered engineer. An un-vented mains pressure system must also have an annual inspection to ensure compliance with regulations and its continued safe operation.

A vented mains pressure system will provide mains pressure hot water to all hot water taps and outlets. It will require a small F and E tank in the loft, or an appropriate place. It will require a small capacity heat-exchanging pressurised cylinder. It will have a vented hot water storage cylinder so there is no risk of explosion due to pressure build up. A vented mains pressure system does not require specialist installation and there is no requirement in relation to informing Building Control. The system does not require any specialist annual maintenance, although general annual maintenance is a recommended procedure.

Where mains water pressure systems are installed correctly, there is considerable benefit to householders in respect of improved energy efficiency and in meeting household requirements for hot water supplies at a convenient pressure.

But as a precautionary measure to spending a considerable sum on a system that is unsuitable, the homeowner should take into consideration the cost of purchase and installation, the flow and pressure rates of the supply, the general running and maintenance costs and the overall safety of the system.

In doing so the homeowner can make an informed decision away from elaborate marketing claims.






Understanding Energy Efficiency Rating Labels

In a way, it is not surprising that energy efficiency has become such an important issue. Never, on a global scale, have we consumed energy at such an alarming and exponential rate. Faced with finite fossil energy reserves and the spiralling costs of extracting the oil and gas from these diminishing deposits, it is fortunate that we can now utilise technology to reduce our consumption and ensure that what energy we do use, is used to maximum efficiency.

It is easy to see how we, as a country, have increased our demand and dependency on energy in the last forty years. Motor vehicles and an abundance of electrical appliances and gadgets have proliferated and become almost essential for modern living.

In the case of central heating, in the 1970’s it was installed in only 31% of homes. By 2003 that figure had risen to 93%. This led to a rise in home ambient temperatures from 12.1 C to 18.2 C and a rise of 4.5 C in homes with existing central heating installations during the same period.

The concept of abundant cheap energy, so much a characteristic of past consumption has been replaced by sharply rising fuel costs and drive towards better insulation of property and the efficient utilisation of heat production.

Appliance manufacturers have responded by specifically designing equipment with energy saving characteristics. Energy efficient products are designed to make the most effective use of energy with the minimum of waste. This means that the amount of energy needed to run them is reduced compared to a standard efficiency product.

All appliances are now subjected to standard testing procedures under a European Union directive, which enables the appliance to be categorised according to recognised levels of energy efficiency, and this information, in the form of a label, is required to be displayed on the appliance. The label is a colour coded graphic which rates products from ‘A’ to ‘G’, where ‘A’ represents the most efficient appliance with a stepped drop in efficiency down to ‘G’ which represents the most inefficient.

These alphabetical grades are used on items such as washing machines, refrigerators, cookers, light bulbs, etc and are designed to help consumers make informed choices when purchasing new appliances.

Although the above system is being adopted as a guide to efficiency by electrical central heating pump manufacturers, when it comes to boilers, a different and more reliable method of efficiency classification is required.

The basic measure of boiler efficiency is calculated from the ratio of the energy input compared to the heat output. High efficiency boilers require less fuel to produce the same amount of heat output to the system compared to less efficient boilers

The ‘A’ to ‘G’ system is still employed, but the method of assessing a boiler by its efficiency capabilities requires additional criteria and produces a rating based upon a percentage. This is because in domestic operational settings, the annual efficiency of the same boiler can be very different from one installation to another. It can be influenced by factors such as the circulation patterns through the property, the varying requirements for heating and the frequency and effectiveness of routine maintenance procedures.

To produce this alternative and more reliable model of classification, laboratory testing of boilers and a theoretical approach was compared with, and complimented by field trials carried out over a period of three years.

This method of rating is referred to as SEDBUK, an acronym for the Seasonal Efficiency of Domestic Boilers in the UK.

Originally launched in 2005 it was revised and updated in 2009 and re-launched on October 1st 2010.

Boilers are rated according to how much of the fuel that they consume is converted to heat represented as a percentage. An ‘A’ rated boiler will have an efficiency rating of 90% plus.

A ‘B’ rated boiler corresponds to 86% – 89% efficiency, with step reductions down to ‘G’ representing 70% and below.

In 2005 it became law that nearly all new boilers being installed had to be SEDBUK rated ‘A’ and ‘B’. These are high efficiency condensing boilers. Under the law, there is provision for some exceptions where ‘C’ and ‘D’ rated boilers may be installed, but these are quite restricted.

The European Union has legislation covering the energy efficiency of everything from homes and buildings to the requirement for the testing and classification of energy consuming appliances. This provides useful guidance for selecting appropriate items and the SEDBUK categorisation of boilers ensures that prospective purchasers of new boilers can be confident that they will purchase energy efficient appliances.

SEDBUK can also be used to obtain the efficiency rating of older boilers already installed in properties to gain some indication of current performance and to compare with new boilers on the market. This can be accessed online by consulting the SAP (Standard Assessment Procedure) database, which holds the information by manufacturer and model.

It can be useful to consider that around 10% of the energy costs of running a gas central heating system can be attributed to electrical components necessary for the efficient operation of the system. These include pumps, electrical diverter valves, flue fans and digital displays on boilers and thermostats.

However, on modern systems, the improved energy efficiency provided by the latest technological advances can considerably outweigh the electrical running cost of the components that contribute.


How to Buy the Best Boiler.

If you are in the market for a new boiler you can guarantee that there will be no shortage of persuasive sales representatives determined to grab your attention, and cash. You have probably already been seduced into the notion that an upgrade to a more modern boiler will deliver fantastic savings on your energy bill. It very likely will, but it may not be you that pockets the subsequent savings. Even the government’s Green Deal initiative grabs most of the money you would expect to save to cover re-payment and interest on a preferential loan.

The market is not quite as competitive as it could be with the major energy providers well placed to exploit customers who may already be signed up to their service and maintenance plans and contracts. Some independent installers are often not as independent as they might have you believe, with many having connections to the major energy suppliers or receiving healthy commissions from various boiler manufacturers.

It can be difficult to know where to turn to for good and impartial advice, and as you probably don’t have a distant cousin twice removed who used to be a heating engineer, or know a man who does, you may have to employ your own intuition to guide you into making the right choices.

One of the best starting points is to consider the type of system your current boiler services, and whether that system is suitable for your needs.

Many existing systems, whether they are open vented or sealed systems, and whether they have open vented hot water storage cylinders, sealed ones or none at all, are quite adequate. The main requirement is that the network of a heating system, which the new boiler is intended to provide hot water into, is in good shape, not too ancient and capable of modification to improve efficiency. It should also have adequate capacity for the household requirements for heating and domestic hot water.

If you are installing a boiler in a new build or complete renovation project you may have already decided to install the latest up-to-date central heating system with a state of the art boiler incorporating a capability to utilise renewable sources of energy. If that is the case then the boiler and system will be designed and installed to complement each other and the installation will be straightforward, and probably quite expensive.

The installation of a new gas boiler into an existing system is quite straightforward. It can also replace a different type of fuel burning boiler, if gas is available. In most cases a new gas boiler will have to be an efficient condensing boiler by law, and rated A or B on the SEDBUK scale, unless there are good reasons why an inferior rated or non-condensing boiler should be fitted. An example of this might be where a householder decides to replace an existing boiler with a cooking range system like an AGA or Rayburn.

Having established the currently installed heating system type and its suitability for continued good service, the next thing to look at is a replacement boiler capable of suiting those specific requirements.

There are three types of condensing boilers available.  Combination boilers, system boilers and open vent boilers. Boilers are available in a range of sizes and it is important to choose one that has the capacity to provide enough energy output to meet the system requirements.

There is considerable research to indicate that fitting a new boiler with substantially greater capacity than is required by the system has no adverse effects on overall energy efficiency. In fact, it is generally accepted that most new boilers fitted have a capacity in excess of requirement. Problems generally occur after the installation of a below capacity boiler when it is discovered that radiators are not hot enough.

It is, therefore, important that your new boiler is suitable for your existing system. A good boiler manufacturer will provide the information you need to ensure that the correct choice and size of boiler is selected. Most new boilers that are fitted as replacements are open vent or heat only condensing boilers, which supply hot water into the existing system of hot water cylinder and radiators.

This brings us on to boiler manufacturers and which offers the most reliable and best value for money appliance.

This matter is a little subjective and it can be argued that value for money is not quite the same as best value. Accordingly, a buyer should have a reasonable expectation of what popular makes of boiler cost. The most popular brand names are usually well tried and tested and combine proven reliability with customer satisfaction. Choosing a boiler from a company with such credentials can lead to peace of mind where the validity of extended warranties and the future availability of replacement parts are a concern.

There are some makes of boiler which are of simple design and quality and which are often the choice of builders, landlords and fit and run installers. These often prove to be poor value for money. Some of these boilers have parts that are simply not durable and consequently have a very limited lifespan. This is not to suggest that these boilers are unsafe. They just represent the lower and functional end of the market.

The best suggestion is to find out what boilers friends and neighbours use and recommend, and to research good quality boiler companies profiles and products on the web. The Energy Saving Trust produces a comprehensive list of recommended boilers.

Finally, a new boiler must be installed by a Gas Safe registered engineer. That person will of course guide you in the choice of boiler and the system requirements. However, before committing to an installation, it would be prudent to seek opinions and installation quotes from more than one engineer. Keep in mind that installation costs will need to be factored into the total boiler replacement cost.

It is generally a requirement that a power flush is carried out on existing central heating pipe-work and radiators at the time of installation in order to comply with a new boiler’s warranty conditions. Do not let an installation engineer circumvent this necessity, or offer to fit a magnetic filtration device as an alternative.

These precautions will help you to ensure you choose and buy the best gas boiler.


What are the Differences between a Combi Boiler and a Conventional Boiler?

Whether you are thinking about having a new central heating system installed or considering converting or upgrading an existing system to improve its efficiency, you will need to decide which boiler system is best suited to your property and your own personal requirements.

With heating boilers accounting for around sixty percent of household energy bills, the choice of boiler is becoming an important consideration, particularly when considering the replacement of older and now inefficient systems.

Combi boiler and conventional boiler heating systems tend to be the most popular of the three main central heating installations operating in domestic properties in the U.K.

There are distinct differences between these two systems. Both offer advantages and disadvantages, but the most important thing to consider is the limitation of each system.

So what are the principal differences?

When it comes to simplicity, a combi boiler has the advantage. It is now the leading type of boiler installed in the U.K. and is the boiler of choice if limited space is a consideration. The boiler can be fuelled by gas or electricity and, dependent on the need for a flue, can be fitted between cabinets in the kitchen or discretely out of sight in an under stairs cupboard. It is fed directly from the mains water supply, eliminating the requirement of system header tanks in the loft. It does require electrically operated pumps to circulate the heated water but these are usually discretely contained within the boiler cabinet.

Although the central heating is managed thermostatically by a regulated heat exchange between the boiler system and the separate central heating system, the domestic hot water supply is provided on demand. When the demand is initiated, a diverter valve operates to direct mains water through the heat exchangers whilst the boiler increases its fuel use and capacity to heat the mains water very rapidly. Once the demand for domestic hot water has been satisfied, the diverter valve returns operation back to the central heating system and the boiler reverts to room thermostat operation.

This system eliminates the need for a domestic hot water storage cylinder, which contributes, greatly to the combi boiler’s space saving qualities.

A combi boiler is compact and easy to fit and can provide unlimited domestic hot water but that domestic hot water tends to have a lower flow rate than the stored hot water of a conventional boiler system, and consequently, does not have the capacity to run multiple hot water outlets simultaneously. A combi boiler is ideal for a modest property although high capacity versions are available for larger homes. A combi system would be unsuitable for a property supplied by a low or variable pressure mains water supply.

A conventional or vented system requires space. The central heating side of the system requires a cold-water storage tank to supply the domestic hot water component and small feeder and expansion tank to supply the central heating component. Both of these are usually located in the property loft.  In addition, a domestic hot water cylinder storage system is required and this is usually situated in the airing cupboard. In some systems, particularly gas fired boilers; this domestic hot water cylinder may incorporate an additional thermostatically controlled electric heating element to provide an alternative power source for that part of the system.

With a conventional system, domestic hot water supply is limited to the capacity of the hot water storage cylinder, and once that supply has been exhausted, say with the filling of a bath, a period must elapse before the stored domestic hot water supply has been re-heated to the thermostatically controlled desired temperature.

However, the traditional system has the advantage of being able to supply multiple hot water outlets simultaneously, although water pressure may become an issue if demand is too great. The hot water available is always governed by the capacity of the hot water storage cylinder.

For households seeking a high degree of efficiency from their boiler systems it might be worth considering that the domestic hot water storage system of a conventional boiler has the disadvantage of losing heat from the cylinder, even when insulated with a cylinder jacket.

In fairness, the choice of system has to be made based upon the requirements of the household, the property characteristics and the limitations of the systems. Whichever system is decided upon it should be borne in mind that the boilers on the market of either system today are vastly superior in terms of energy efficiency than their counterparts of ten or even five years ago.

However, boiler efficiency is a combination of many factors including regular maintenance and sensible energy consumption. There would be little or no benefit obtained by replacing an old boiler with a new energy efficient one without thoroughly flushing and protecting the old radiator system and installing new thermostats and system programmers to compliment and regulate the efficient running of the system.

Improving and maintaining the energy efficiency of your own home is the only answer to the present fluctuations in market price and the predicted long-term increases in the cost of energy.

Replacing a Cold Water Storage Tank.

If you have an indirect or gravity fed domestic hot water system, you are bound to have a cold-water storage tank somewhere. It is usually located in the loft space.

This tank supplies the hot water cylinder and often all the cold taps, except for the kitchen tap which is serviced directly by the rising main and used for drinking water.

In older houses, an old heavy galvanised steel water tank is often found. Many will have been in use since the house was built and often they were placed in position before the roof and slates were added.

Unfortunately, these tanks corrode over time. Many of the older ones have long since been replaced, but some remain. Some may have been patched up with epoxy resin to try to prolong their useful life, but if you find that you still have one in place it might be best to consider replacing it. If an old tank happened to rupture due to corrosion the resulting water damage would be considerable.

Even where a relatively new polyethylene tank has been installed, it may still be necessary at some point to replace it due to damage or lack of capacity.

Replacing an existing tank for whatever reason is a relatively straightforward task.

Firstly, it is a good idea to consider the size of tank that will be used as a replacement. Tank capacities vary from 25 to 55 gallons. A modest sized home with a family of four should find a 50 gallon tank more than adequate for their needs. It is also a good idea to ensure that the joists in the loft space are in good condition and able to support the weight.

New polyethylene tanks come in a variety of shapes, from rectangular box, to coffin flat or round cylindrical. This means that any loft or attic space can be utilised with a suitable tank. However, working in a confined loft space can be challenging for the installer. Most modern polyethylene tanks are designed to be folded to allow them pass through the usual narrow entrance hatch that leads into the loft space.

To be confident that a new tank will be durable and comply with the standards required for drinking water look for the WRAS approved product logo.

It is important to ensure that a new polyethylene tank comes supplied with a suitable tight fitting lid and all the legally required fittings to comply with byelaw 30. Byelaw 30 is part of The Water Supply (Water Fittings) Regulations 1999. The fittings are often supplied as a Byelaw 30 Kit. These fittings are specially constructed to prevent light or insects entering the tank.

The tank should be supplied with a reinforcing plate to make the area where the ball valve connects rigid. You may also require a special screen fitted onto the overflow pipe and a good quality tank insulation jacket. The tank must also sit on a firm, flat, supporting board base to distribute its weight.

When working in a loft ensure adequate lighting and ventilation. Take care to provide suitable boarding to walk or crawl on and always take care when operating machinery or using tools in confined spaces. It is always a good idea to have an assistant on hand in case of any difficulties.

Before a new tank can be installed, the old tank must be disconnected. First, ensure that any boiler or heat source has been turned off, or fires extinguished. Next, turn off the domestic incoming mains at the main stopcock. Then drain the system though a suitable hot water tap. If there is any sludge in the bottom of the tank, it would be a wise precaution to prevent this material from draining through into the system. It is better to turn off the drainage tap when most of the water has been drained and remove this material with a scoop and bucket.

The old tank can then be disconnected. When disconnecting the various pipes it is a good idea to label them in accordance with their purpose. This will prevent any confusion when connecting pipes to the new tank.

If the old tank is constructed from galvanised steel, it is unlikely to be able to pass through the loft hatch in one piece. It is possible to cut the tank up into smaller pieces with an angle grinder. Alternatively, the tank can be moved to another position out of the way and simply left in the loft.

The new polyethylene tank can now be moved into position. It must be ensured that the tank sits firmly on its base.

Before the fittings can be connected, holes will have to be made into the tank at the appropriate positions. A hole saw attached to an electric drill is the best tool to produce a perfectly circular hole. The installation instructions will provide guidance relating to the correct hole diameters and other fitting instructions, however, the sequence of fitting procedures are generally as follows:

To accommodate the ball valve, first cut a hole 75 mm below the rim of the top of the tank. It is important to ensure that the hole is on the correct side of the tank. Then attach the reinforcing plate securely. Take the ball valve, slide a washer onto the valve thread, and pass it through the hole. Place a washer and securing nut on the external thread of the valve and then tighten all the connections. Cut holes for the distribution pipes 50 mm above the base of the tank and slip a washer onto the connecters, pushing each through their respective hole. Add the required securing nuts and tighten. It is a good idea to also add a couple of gate valves to the distribution outlets to facilitate future maintenance. Applying PTFE tape to all threaded components will ensure secure, watertight connections.

To install the overflow connectors, drill a hole opposite the ball valve 25 mm below the level of the ball valve water inlet. Attach the connector with washers and securing nuts.

The tank can now be connected to the various supply pipes. Ensure all fittings are of a compression type. It is not possible to use hot soldered joints on a polyethylene tank for obvious reasons. The overflow pipe must maintain a continuous fall to its outlet, and that external outlet must be visible to allow observation of overflow should it occur. It is important to clip and secure all pipe work to secure it and prevent vibration from weakening connections.

Once all connections have been securely attached, the mains water can be turned back on. It is important to observe the filling process to check for leaks and to ensure that the ball valve operates correctly. It may need some adjustment to ensure that the correct water level is achieved and maintained in the tank and that the overflow pipe can operate if necessary. When fitting the tank lid, ensure that the vent pipe fits into correctly into its hole to allow venting back into the tank.

Finally, do not forget to add a suitable insulation material around the tank and exposed pipe-work. Do not provide insulation under the tank. Any rising heat below the tank will protect the contents against frost.

Remember that the installation must comply with the relevant requirements of the Water Regulations (Water Fittings) Act 1999.

Hydronic Fan Convector Heaters.


Not so long ago, the mention of a central heating system conjured up images of a groaning hot water boiler and unsightly, large and obtrusive radiators. Central heating also seemed synonymous with unreliability and was, for the most part, quite inefficient in comparison with today’s whispering condensing boilers and obedient, thermostatically zoned and controlled domestic environments.

Radiators too have come a long way from their early counterparts with slimmer designs and personalised finishes, turning them into either focal points or discretely camouflaged installations.

It is not uncommon to find one, or sometimes two radiators heating a large room, but for smaller properties, space can be at a premium. Even a smaller sized conventional radiator can take up a considerable amount of wall and room space.

There are alternatives to conventional radiators, such as under-floor and trench heating systems, but these can prove costly to install and are not appropriate for multi-storey accommodation.

There is one alternative to conventional radiators available that can solve many of the issues relating to limited space and energy efficiency. Hydronic fan convector heaters can be installed. These can form part of a dedicated new central heating installation, or be installed as replacement radiators on an existing system. They can also be added as a supplementary form of heating on an existing system to run alongside conventional radiators.

Most domestic hydronic fan heaters can be plumbed into a two pipe heating system via the heater’s 15mm connectors and will require an electrical supply to operate the fan component. Most models will also require balancing and the installation instructions will indicate if this is the case and the required procedure.

The heating system can be supplied with circulating hot water from any type of boiler or from any of the numerous renewable energy sources that are now available to householders. Because of the method of operation of hydronic fan heaters, a lower temperature of the circulating heating fluids can be efficiently exploited making these types of heater suitable for utilising heat extracted via heat pumps. Subsequently hydronic fan convectors can operate effectively with heating fluid temperatures as low as 40° C.

Hydronic fan convector heaters work by utilising a fan to draw air from the room into the appliance. The air passes over internal fins that carry the circulating heating fluid. Heat is exchanged from the fins to the moving air and directed by the fan to the air exit point. Because airflow is controlled by the fan, the heated air is pushed into a downward flow pattern and gently leaves the heater in a downward direction towards the floor where it then rises dispersing heat.

This method of operation is considerably more efficient at heating a room quickly than the normal convection currents created by conventional radiators. It is generally accepted that hydronic fan heaters are up to 30% more efficient than conventional radiators and when operating they produce an even temperature throughout the room.

The fan requires an electrical input of 30 watts; however, the savings in heating energy requirements more than offsets the cost of the electricity.

Air drawn into the hydronic fan convector heater by the fan also passes through a filter that removes dust and other air-borne particles. This helps to reduce the amount of respiratory irritants that normally circulate on moving air currents.

Hydronic fan convector heaters can be thermostatically controlled or operated manually. Some models have variable fan speed settings to suit the user’s requirements. Many models incorporate a sensor that prevents the heater operating automatically if the circulating central heating fluid is not at a minimum, pre-set temperature. Manual controls will override this function to enable the fan to blow cold air into the room, a feature that can provide a cool air circulation in summer.

Most fan convector heaters are a fraction of the size of traditional radiators and consequently less central heating fluid is required in the heating system. This means the boiler or heat pump has a smaller capacity of fluid to provide with heat. This, combined with a lower hot water operating temperature requirement, contributes to the energy efficiency and a potential fuel cost reduction in the home.

Due to their compact size, hydronic fan radiators allow the space that a conventional radiator would occupy to be put to an alternative use. In a kitchen, the installation of a horizontally profiled plinth hydronic fan radiator incorporated into the base of a fitted kitchen unit frees up wall space for additional units or domestic appliances.

In other rooms, alternative designs and models of hydronic fan convector heaters can be installed in harmony with the room’s décor, or to fit in with the room’s limitations. Some models are designed to be fully recessed into a wall making them flush with the wall’s surface. Other models are designed to be wall mounted and are stylishly finished to enhance their surroundings whilst occupying a small area on the wall.

There are some hydronic fan convector heater models that are of a similar size and appearance to conventional radiators, delivering heat in a traditional radiant and convection mode, but because of the additional fan directed air flow, are considerably more efficient in their energy usage and heat distribution capability.

Some models of hydronic fan convector heaters have a dual fuel heating facility utilising an electric heating element. This can be a useful function when the boiler heating is turned off in summer. Early and late in the season occasional cold mornings and chilly evenings may not warrant the running of the central heating system. Using the electric element function can provide for this temporary shortfall.

Where an aesthetically nostalgic and traditional atmosphere is required in a room, there is a model that incorporates the visual simulation of an open fire, flickering flames, hearth and surround with a hydronic fan heater combined.

Hydronic fan convector heaters are readily suited to environments where age or infirmity raises safety issues. Because these heaters are designed to operate at lower temperatures than conventional radiators, the risk of accidental contact and burning is removed. This makes them ideal for children’s bedrooms or accommodation used by particularly vulnerable adults.

Hydronic fan convector heaters can provide any easy alternative and solution to the limitations caused by buildings, or by the unsuitability of other types of efficient heating systems. Their low installation and operating costs make them a suitable option for consideration when installing or upgrading a wet central heating system.