Hot Water Airlocks in Indirect Systems


Air trapped in the water supply pipework can cause homeowners considerable inconvenience, particularly when it becomes a recurrent problem. Central heating airlocks are generally easy to resolve and may simply require the bleeding of radiators.

When the air becomes trapped in the domestic hot water supply, dealing with it can become a little more complex.

The presence of low pressure at a hot water outlet may be caused by a number of problems. If the problem seems to be restricted to one outlet, it may be worth checking to see whether a filter is incorporated in the tap or device. Filters in tap fittings occasionally become blocked with limescale and other debris or mineral deposits. The filters can be removed and cleaned.

In old hot taps, damaged washers or excessive wear and tear can lead to flow problems. Older taps are better replaced with newer ones.

Internal filters in shower devices, particularly electric ones, are a specialist task and should be serviced by a competent person.

Where low hot water pressure occurs frequently, with or without air locking problems, it is important to check whether the mains supply to the water storage tank in the loft is sufficient. It might also be necessary to check the tank’s capacity to ensure it is sufficient to meet demand. Where water flows out of the tank faster than it can be replaced, the potential for air to enter the system is greatly increased.

Blockages can also occur in ball valves that restrict the flow of mains water into the tank. To check mains pressure at the ball valve, place a finger over the valve outlet and press down the ball cock. It will be impossible to prevent good mains pressure water from escaping around a finger. A blocked valve should be cleaned.

Airlocks may also occur if a storage tank runs dry when the mains water supply is interrupted, for instance due to a provider carrying out maintenance work on their system.

Where the mains supply is sufficient and yet all the hot taps are experiencing low or non-existent flow rates, an airlock in the system is the likely cause.

There are a number of ways to try to remove an airlock. If the mains water supply is delivered by a single cold-water tap at the kitchen sink, it is possible to firmly attach a length of hose from the spout of the cold tap to the spout of the hot tap. With the hot tap turned on, the cold tap should be gradually opened. Cold water at mains pressure will flow into the hot water system forcing any air through the system and back into the cold-water storage tank in the loft. The cold water should only need to flow for a few seconds to clear the pipes.

If the tap at the sink is a mixer type, it may be possible to cover the outlet spout with one hand. Then, with the other hand turn on the hot tap followed by the cold tap. Water will be forced from the cold into the hot tap completing the process outlined in the above method. A short length of hosepipe firmly attached to the spout and with both taps open can offer an alternative to using a hand. With the cold water flowing, tightly nip the hosepipe. This will force cold water into the hot water system.

On some mixer taps, non-return valves are installed internally to prevent backflow occurring. If this is the case, the above method will not work. However, an alternative method can be used. If a washing machine is installed and connected by hot and cold separate pipes, it is possible to turn off the supply valves to the hoses, disconnect them from the machine, join them together and turn on the hot, and then cold supply valves. Provided that the cold supply is at mains pressure, the cold water will force itself through the hot water system, hopefully taking the airlock with it. The supply pipes can then be reattached to the washing machine.

If these methods fail to remove the airlock, a final method is to turn off a suitable hot tap at its isolation point. This is usually a small valve located on the pipework supplying it. It is then necessary to dismantle the tap to a point where it is possible to attach a length of hosepipe. The other end must be attached securely to a cold tap supplying mains pressure. With the hot tap isolation valve open, turn on the cold supply and allow the cold water to enter the hot water system and flush out the airlock into the main storage tank. Once this is accomplished, turn off the main water tap. Close the hot tap isolation valve and reassemble the tap.

It is a good idea to have an observer stationed at the water tank in the loft with any of these methods to confirm successful operation and to warn of any danger of the tank overflowing during the process.

Repeated airlocks can sometimes be caused by air being pulled back into the system through the water expansion pipe. It is worth getting someone to go into the loft and cover the expansion vent pipe exit with their hand. At the same time have someone turn on the lowest hot tap on the circuit. This can force trapped air out of the system.

If these methods fail, it may be necessary to drain down the entire domestic hot water system.

First, ensure that the boiler and all pumps etc are turned off. Turn off the water feed to the storage tank. Then open all the hot taps to drain down the system. If any sludge is visible in the bottom of the tank, avoid allowing this material to be drawn down into the pipe-work. Sludge should be removed with a suitable scoop and bucket and the tank disconnected and cleaned correctly.

Once the system has drained, go round and close each hot tap until they are about three-quarters closed. Now turn the water supply to the storage tank back on. The tank will start to fill and eventually all the taps should have a gentle flow of water. Adjust each tap slightly so that the flow rate through each is similar. Starting with the lowest in the system, work upwards with each hot tap, turning them on further about half a turn. Return to the first tap and repeat the process again. Keep doing this until all the hot taps are fully turned on and all the air has been removed. The next step is to slowly turn them off until each tap has just a trickle. Let them run for a minute or so and then turn them all off. Do not forget to restart the boiler and any associated pumps when the task is completed. If the water pressure is particularly low, it may be necessary to fill the storage tank prior to operating the taps.

If this does not solve the problem, it is time to call in a professional to ensure that the problem does not lie elsewhere within the system.




Earth Bonding in Domestic Property

Electricity is something we all take for granted. It is the unseen force, a stream of moving protons and electrons, which powers our machines and appliances. Perhaps the only time we give it much thought is when we receive the bill for consuming it.

However, this force, safely restrained within insulation cables, can be extremely dangerous if it is allowed to behave naturally. Electricity continually seeks to dissipate its energy by escaping from a circuit and flowing to earth.

This natural tendency is all well and good. So long as a person does not form part of a pathway allowing it to do so. A flow of electricity passing through a person to earth is commonly referred to as an electric shock.

In passing through any material towards earth, including a person, the electricity encounters resistance. Overcoming the resistance generates heat. This heat causes severe internal and external burns as it passes through a person. The flow of electrons also interferes with the natural electrical activity in the body causing severe damage and possible death.

Electricity will always find a route to earth that offers the least resistance. Faced with the option of a copper earth wire and human flesh, the electricity will choose the earth wire, plus a bit of the flesh.

In an attempt to prevent electrical shock, or damage to appliances caused by a sudden surge in electrical current, all circuits carry a fuse system. A surge in electricity will break the resistance tolerance of the fuse causing it to melt and cut the circuit. The fuse acts as the first line of protection in electrical circuits.

Domestic electrical circuits have to incorporate an earth circuit (PE).

In electrical terminology, earth is represented as ‘T’. This ‘T’ can take a number of forms. An earthing rod buried into the external ground of a property and forming an earth circuit through the electrical appliances would be referred to as ‘TT’. External earthing rods can be poor earth devices. A good earth requires a good contact with earth. The soil around earthing rods can dry out, shrinking away from the rods and causing poor earth contact.

Most homes utilise a TNC-S earthing system. ( N=nuetral, C=Combined, S=Separate) or better known as PME (Protective Multiple Earth).

With PME, earthing is carried by the supply company’s main earth back to the nearest sub-station. This earth is particularly good and reliable.

Bonding, on the other hand, is designed to prevent a disparity between electrical voltages if a fault occurs. Where a sudden release of electricity flows from an appliance, prior bonding of the metal in that appliance to other circuits that could contribute to creating alternative earth paths limit’s the voltage change potential.

There are two types of bonding, main bonding, and supplementary bonding.

Main bonding provides an interconnection between incoming metallic services such as gas and water. It is on these services that the householder will generally find the usual earth bonding yellow and green wires clamped to the pipe-work. There will also be main bonding joined to any metal fabric of the home, such as supporting iron and steel building construction materials. This earth bonding also provides protection in the event that it is the supplier’s earth that is causing the problem.

Supplementary or cross-bonding joins together metal components that could provide a circuit to earth, for instance if a fault developed on a towel rail in a bathroom and resulted in its surface becoming ‘live’, a person touching it and also touching a tap at the same time would form a circuit. Supplementary bonding links the earth across all these metal surfaces to reduce the destructive force of an electric shock. These bonding clamps can be seen on pipes and other metallic connections in bathrooms etc.

The final safety device in the home is performed by Residual Current Circuit Breakers (RCB’s). These devices monitor and detect changes in the steady and balanced flow of electrical current through the positive and negative wiring supply to appliances. A sudden leakage to earth, whether it be by an electric shock or other means of dissipation, will be detected almost instantaneously by the RCB. This will cause the RCB to operate (trip) and immediately break the circuit, significantly reducing the potential for harm or damage.

Although the complexities of earthing and bonding are possibly beyond the scope of DIY enthusiasts, the importance of supplying and maintaining them is not. It is most important that where a homeowner undertakes any remedial work to the property, or to the plumbing and electrical components, that earthing is provided and maintained.

When installing plastic pipework into a copper plumbing network, it is important to ensure that electrical bonds are maintained. This may entail building a bonding bridge between the plastic pipes and the continuation of the copper network to facilitate continuity.

Likewise, when working on pipe-work, cutting into a section of copper pipe during plumbing work will interfere with the bonding circuit. It is a wise precaution to temporarily provide a bonding bridge for electrical safety reasons.

Installing supplementary and cross bonding wiring is a simple procedure. Clamps and regulation-sized earth wire are easily obtainable from DIY and electrical suppliers. Bonding cables must run unbroken and continuous to the main earth block in the mains domestic consumer box, or the dedicated earth block located near it. It is possible to link supplementary bonding cables across platforms, such as bath taps to shower to towel rail, but main bonding must be continuous.

Homeowners should periodically check main and supplementary bonding cables and clamps to ensure that they continue to provide secure and serviceable operation. Any earth or bonding cable that becomes detached must be immediately replaced.

Although attaching earth and bonding connections does not carry any restrictions under the Building Regulations, anyone undertaking such work should make themselves acquainted with BS 7671 of the Wiring Regulations.

As always, any electrical work must be performed competently. Insurance cover may be affected by problems caused by substandard work. It is most important to seek professional advice when attempting to work on electrical installations. Building Regulations state that only certified persons can carry out electrical installation work.

Pipe Freezing Kits and Machines

Sometimes it can be the simplest job, such as changing a tap washer. At other times, it can be something slightly more complex, perhaps changing a radiator valve. Whatever the task, the thought of having to mess around trying to turn off a seized mains stopcock or drain down a central heating system, can initiate a certain amount of procrastination.

At other times, an urgency such as the repair of a burst pipe might be frustrated by the inability to locate either the domestic or the water provider’s main stopcock.

Whichever, the process of freezing and creating a plug of water in the supply pipework to temporarily interrupt the flow can be a quick and efficient method of facilitating a plumbing procedure.

Using a pipe freezing process is ideal for cutting the water supply in the immediate area to allow for the plumbing of T-pieces for appliances, radiator valve changes, pump and zone valve replacements. It can even facilitate the repair or replacement of a seized mains stopcock.

Pipe freezing can be accomplished by using refrigerants provided by disposable aerosol canisters or by specialised, electrically operated portable machines.

Aerosol canisters are designed to operate in conjunction with a dedicated kit. This kit comprises of thermal sleeves that wrap around pipework and valve connector attachments with refrigerant delivery tubes. These sleeves are usually made of durable nylon material.

Thermal sleeves come in a variety of sizes to fit the common pipe diameters in use today. The thermal sleeves act as a barrier to contain the evaporate and to delay thawing.

The refrigerant is a volatile gas that has been compressed to form a liquid and then held in that state under pressure in the canister. It is the sudden reduction of pressure that enables the liquid to return to its gaseous form. In doing do, it draws heat from its surroundings. This causes the freezing action.

For plumbing purposes, the thermal sleeves are applied to pipes and the liquid gas introduced where it evaporates to form an ice plug close to the working area, and if necessary, at a point beyond to prevent backflow. There should be a distance of at least 200 mm between the working area and the sleeve (s).

The process works best on horizontal pipework, but can be used on a vertical pipe.

There must be no flow of water through the pipes at the time of freezing, as this would inhibit the formation of an ice plug. Boilers and pumps must be turned off and leaks temporarily patched. The water in the pipes must also be cold, with the ambient room temperature below 20 degrees C for optimum efficiency.

One end of the flow pipe for the refrigerant is attached to the thermal sleeves, which in turn must be securely fastened to the plumbing pipework. The other end of the flow pipe is attached to a valve located on the canister. By operating the valve, the liquid under pressure in the canister passes down the tube into the thermal sleeve, where it expands and converts into a gas. This causes water in the plumbing pipe to freeze and form an obstructing plug of ice. The obstruction blocks the water flow. The refrigerant should be delivered in short bursts to prevent wastage or overspill. The thermal sleeves must remain in place until the plumbing work is completed. A naked flame and blowtorch cannot be used and plumbing fittings that are to be installed must be of compression or other non-heat requiring types.

Depending on the pipe-work material and diameter, and the ambient temperature of the water and room, the plug will form in copper pipes in around five minutes. Plastic pipes will take up to twenty minutes. An audible click from the device will inform the user that the plug has formed and that the plumbing work can commence. The ice plug will effectively prevent water flowing for about thirty minutes although it is possible to maintain the plug with further bursts of refrigerant.

It is important to ensure that there is sufficient aerosol refrigerant to complete and prolong the plumbing if it becomes necessary. The aerosol and gases produced must be used in a well-ventilated area. The refrigerant will cause serious burns if it comes into contact with skin or eyes and must not be inhaled.

Pipe freezing machines are an alternative to using a disposable canister. The principal of freezing the pipes is similar, however, the gas evaporation and re-pressurising is contained within the machine and is much safer to use. It is also environmentally friendly as no toxic gases are released into the atmosphere.

The machines are electrically operated and will supply and maintain a freezing process to pipes indefinitely, so long as the power supply is maintained.

The refrigerant is delivered via pipes to clamps attached to the pipework. The freezing process and maintenance are automatically controlled by the machine, which will also indicate when the ice plug has been formed. The clamps and the freezing process must remain in place until the work is completed.

There is a variety of machines on the market and manufacturers make machines that are capable of freezing any diameter of a pipe. The larger machines are regularly used by water companies to complete major pipe maintenance work.

Pipe freezing machines are expensive to purchase but can be hired on a daily basis from plant and tool hire companies. Currently, expect to pay around £50/day.

Both methods of freezing pipes for plumbing purposes are very effective if the manufacturer’s instructions are followed. Occasionally, where pipes are located in confined spaces, or very close to walls, neither conventional sleeves nor clamps can be effectively used. With pipe freezing machines there is a type of clamp that is held in place by rubber straps. The clamp freezes one side of the pipe and will take longer to form an ice plug. However, this can be used effectively where a normal clamp may not fit.

When cutting pipes to facilitate plumbing work, consider implications surrounding earth-bonding issues with electrical supplies.

For a one-off job, pipe freezing aerosols, and the kits that are available to facilitate their use may be the most practical option. Inclusive kits vary in price depending on size and the required application. A very simple kit can be purchased for around £30. Fittings and gas canisters can also be purchased individually. The kits and accessories are widely available from plumber’s suppliers and DIY outlets.



Problems with Dead Legs

I recently bought a new washing machine. Not that there is anything particularly out of the ordinary in doing so. The working life of a modern washing machine seems to be considerably shorter than that of the robust models of the past. Whether that is due to the increasing complexity of the electronics or the designed-in time-dependent failure of its components is a matter of opinion.

The main thing that did attract my attention was the fact that the new machine had just one water inlet hose. My previous washing machine had two independent water inlet hoses, one for hot and the other for cold water supply.

It seems that now one cold supply hose is the only water inlet connection required.

This naturally left a length of redundant hot water supply pipe. Although it was fitted with an inline valve to close of the hot water flow, I decided to fit a blanking cap to the hose connection end as a secondary precaution against leaks.

Unknown to me I had just created a dead leg.

That might have been the end of the story had I not read an article about the increasing awareness of the potential problems of microbial proliferation in domestic water supplies, particularly in dead legs.

A dead leg is a section of water pipe that branches from a T-junction and is blanked-off due to it no longer being required. It can also refer to a section of water pipe that services an appliance that is infrequently used.

Apparently, such lengths of pipework can become traps for silt and organic material. This provides the perfect environment for the development of microbial agents that can pose a danger to householders.

This is particularly the case in respect of dead legs on hot water systems.

Although hot water may be flowing through the domestic system at a temperature and flow rate that prevents microbial development, a dead leg remains as a sump for collecting debris.

The water temperature in the main domestic circulation is usually at a high enough temperature to inhibit microbial growth, but in a dead leg, the water stagnates at a lower temperature.

The dead leg on a hot water system may pool water at the optimum temperature to allow scale formation. The surface provided by developing scale, the presence of nutrients from collected sludge and the warmth from the water provide the ideal environment for the development of dangerous organisms.

Organisms such as Amoebae, Ciliates, Coliforms and Algae may proliferate and disperse into the main circulation. However, Legionella and Pseudomonas bacterium can also flourish.

So how do these organisms get into the hot water supply to begin with?

Mains cold water from the provider is chlorinated to destroy most potentially harmful organisms, but contamination can still occur due to leaking supply pipes or unprofessional plumbing work.

Perhaps the greatest source of contamination is a water storage tank, particularly one that is uncovered or that has an unscreened overflow pipe.

Although regular flushing of the hot water system, either intentionally as a maintenance task or by continual domestic usage, will help to prevent microbial contamination, dead legs will remain un-flushed and prone to scale formation. The scale provides a perfect material for organisms to adhere to.

Fragments of contaminated scale can break away from formations in dead legs and become suspended in the domestic water flow.

In the case of Legionella, the bacterium can survive the flowing hot water temperature and then incubate in lengths of T-pipes supplying hot water outlets when the temperature drops in-between outlet demand.

The bacterium can also thrive in showerheads in-between usage, particularly where scale buildup in the showerhead provides niches for development.

Although microbes in contaminated hot water can be harmful if ingested, bacterium like Legionella pneumophilia can be dangerous when inhaled.

The inspiration of aerosol particles can penetrate deep into the lungs.

Aerosols are minute water droplets suspended in the air. They are created by water falling onto a hard surface; such as occurs when running a tap, a bath, or having a shower. Flushing a toilet or spraying water will also produce aerosols.

Whirlpool and Jacuzzi type bath installations are now being identified as potential sources of microbial incubation and harmful aerosol formation, particularly where regular sanitation and cleaning maintenance is neglected.

Aerosol particles in the air can remain suspended and circulate on air currents for over twenty minutes.

Although Legionella infections are not passed from person to person, they do occur in clusters. The symptoms can vary from mild flu-like conditions to life-threatening pneumonia. People with compromised immune systems or pre-existent lung conditions are the most vulnerable to acquiring Legionella infection. The mortality rate can be high among confirmed cases in susceptible people.

However, it is thought that many mild cases go undiagnosed and that the incidence of Legionella infections amongst the population is much higher than the identified and confirmed cases suggest.

On the Continent, plumbing procedures encourage the installation of loop systems rather than T installations to help to prevent microbial development problems in domestic hot water supplies.

Best practice and Water Regulations now issue guidance on dead legs and associated blind ends. It is recommended that redundant T water pipes are removed and the T replaced with a standard in-line pipe connection.

It is also worth noting that landlords of rented properties must undertake a risk analysis of the potential for water-borne infectious agents to develop in services installed in properties they let. They must also take action to make safe any potential sources of microbial contamination. Failure to do so can expose the landlord to criminal action and substantial litigation issues should subsequent related harm occur to a tenant.

I have now removed my blind end and in conjunction with a regular flushing of my entire domestic hot water system, can rest assured I am doing as much as practical to reduce the chances of my household contracting a water-borne infection.




DIY Copper Plumbing and Fittings

When it comes to carrying out maintenance tasks or simple repair work within the home, nothing can give as much satisfaction as DIY. The pleasure that comes from identifying and successfully completing the required work adds a certain feeling of being in control of, rather than being controlled by the technology and installations within the home.

It is also fair to acknowledge that being able to do all or part of the work that would normally require the intervention of a plumbing or heating engineer is likely to save a considerable sum of money. However, the ambitious DIY enthusiast should apply some caution to ensure that any work undertaken is within the scope of the enthusiasts’ skills and capabilities. Where DIY goes wrong, the cost of putting the situation right can be costly.

Although there are many materials available to the DIY heating and plumbing enthusiast, copper perhaps is the most widely used and most durable material.

All alternative pipe-work materials have their place and many offer an ideal substitute for copper for those who would prefer not to learn the basics of working with that material.

Yet learning how to install copper pipes and fittings can be a joy in itself and although skills are not learned overnight, the basics can be understood very easily. Getting the practice that would ensure any work carried out was as good as that of a professional would be another matter, but the same could be said when using alternative materials.

Copper is a proven, durable and reliable material, which is still the choice of artisan tradesmen, and when installed correctly makes the extra time it takes to install it aesthetically and visually worthwhile. It might be expensive to purchase when compared with some plastic alternatives, but copper and its brass fittings retain a scrap value and are completely recyclable.

Copper pipe comes in a three basic types. Thin, medium and thick-walled. Medium walled is a general type for domestic use. It can be purchased in rolls or in specific lengths. There is a flexible type of copper, suitable for repair work, and a rigid type of copper for general installations. Copper comes in a variety of diameters from 1/4 inch to 2 inches.

There are three categories of pipe fittings. The first category includes fittings designed for making bends and turns in the pipe. The second category has fittings made for joining or branching copper pipe. The third category is comprised of couplings, slip couplings, cast iron and other pipe-work adapters. All of these fittings can be used with either rigid or flexible pipe.

Copper pipe can be cut to the required lengths with either a dedicated pipe cutter or a hacksaw. It is important to ensure that the cut is vertical to the horizontal pipe to ensure a tight connection into the coupling. Once cut, the cut surface must be thoroughly cleaned externally with an abrasive material such as steel wool. The internal cut area must be reamed with a knife or suitable implement to remove any burs which, if not removed, can interfere with the smooth flow of water through the pipe causing erosion and corrosion.

Any coupling that is to be used must also be cleaned to remove debris that could affect the integrity of the join.

Copper pipe can be joined together in a number of ways. Brass compression fittings can be used to secure pipe joints. These rely on the deformation of an olive placed on the pipe. Pipe threads are wound with PTFE tape prior to compression. Applying a tightening procedure to the nut on the compression fitting compresses the olive into the joint with the copper pipe and brass fitting producing a watertight seal.

Adhesives are also available for joining copper pipes and fittings. These are designed to withstand water temperatures up to 300 degrees F. an adhesive might be suitable for use in some installations and repairs but would generally be regarded as unsuitable for extensive work.

Soldering and brazing are perhaps the most widely used methods of joining copper pipes. Soldering is suitable for general purpose. Brazing requires greater heat and metal fillers to replace the traditional solder. Brazing is best suited to systems that are likely to operate with a high working pressure.

Copper fittings can be purchased that are already primed with solder and simply require the joints to be cleaned. Flux should be applied to the externally cleaned pipe work and the internally cleaned core of the fitting prior to soldering. Flux is a compound that prevents oxidation of the copper pipe when it is being heated for the soldering process. Care should be taken with flux to avoid skin and eye contact or accidental ingestion.

Joints must also be completely dry to ensure a secure and reliable joint.

Prior to soldering or brazing, the pipework must be suitably secured to prevent any movement or vibration that might affect the integrity of the joint. Any vibration or movement will prevent the solder from setting properly and will result in a joint that is likely to fail.

For general soldering, the successful joining procedure is achieved through solder being drawn into the narrow space between the pipe and the coupling. This is achieved through capillary attraction. The pipe and joint area are heated to a point that will allow the solder to melt and run freely into and around the joint. Excess solder can cause problems if it enters the pipe-work interior.

Gauging the amount of heat required and the amount of solder to apply comes with experience gained through trial and error, however when heating the pipe with the blue part of the torch flame, a slight change in the flame colour from blue to green will indicate that the joint has reached a temperature suitable for the application of the solder. The solder should be applied carefully until it can be seen that the solder is starting to fill the joint cavity.

Care must be taken when using blowlamps to minimise the risk of fire or injury from burns. Soldered and brazed joints should be allowed to cool naturally prior to close inspection to establish whether the joint is secure. Where solder or metal filler has not completely filled the space in the coupling, the area can be fluxed again and reheated and a touch of solder or metal filler applied to remedy the situation.

It is possible to bend copper pipe to accommodate physical features in the building’s construction. This is often quicker than cutting, joining and soldering. The pipes can be bent using a specialised pipe bending apparatus. These are quite expensive to purchase and for DIY, a much cheaper alternative is a pipe bending spring. This is a length of spring coil, which is inserted into the pipe. With the spring in place, the pipe should be gradually bent to the required shape. If the pipe is bent with a sharp force, there is a risk that the bend will be formed with a rippled profile. This should be avoided.

Copper pipe cannot be successfully bent without one of these instruments.

Working with copper can be a satisfying procedure and is one that can be learned quite easily. As in all matters, practice with hands-on experience is the best way to learn.

Renewables and Intermittency

Energy surrounds us. Light and movement combine in a dynamic process of transforming energy from one form to another. Perhaps, like me, you can remember school physics teachers remarking that ‘energy cannot be created or destroyed; it just passes from one form to another’.

So, what is the problem with current fuel supplies?

Simple. Because of our increasing demand for energy and our over reliance on what might be still considered cheap fossil fuels, we are coming close to exhausting fossil fuel reserves altogether. We take electricity and natural gas for granted. As a minor example of a more serious and complex situation, our toys and gadgets like computers and mobile devices use little power individually. However, on a global scale, it takes the combined fuel output of several fossil fuel burning powers stations just to power the servers that supply the World Wide Web, which these devices rely on. Moreover, that does not include the power used to run the devices, the power used to create the devices and the power required to extract and purify the materials used in the devices’ construction.

Of course, fossil fuels are renewable. The problem is that they take millions of years to form and unfortunately, we cannot sit back and wait.

Nuclear fuel was once heralded as the saviour for human energy requirements, however, such salvation has not only became a nightmare regarding the security issues surrounding the storage of spent fuel, the cost of building and the short life and subsequent de-commissioning costs of nuclear power stations makes the electricity they produce very expensive indeed.

Tapping into other energy sources around us is really quite simple. However, the cost of doing so can be a disincentive without government funding.

Renewable energy sources can be divided into two categories. Intermittent supplies, such as wind, wave and solar.

Non-intermittent supplies like energy crops and biomass, methane digesters, hydroelectric and tidal barrages.

Although all of these have some characteristics that can make them either difficult or unethical for considering as large-scale energy converting systems, the intermittent types pose the greatest challenge.

Intermittent energy sources are, as their name suggests, unreliable or perhaps more appropriately, unpredictable in their output. They are what is termed ‘The Achilles’’ Heel’ of renewable energy supplies.

As such currently they can only be used viably as an addition to the energy demand as electricity supplementing the National Grid.

In looking at conventional UK human activity and power requirements, it can be seen that demand for power is lowest between 11.00 pm and 6.00 am. Energy demand increases slowly during the day and then reaches a peak between 6.00 pm and 8.00 pm. Being able to respond immediately to peaks and demands, particularly those that are unpredictable like supplying increased energy during a cold spell of weather, requires a responsive power source. Intermittent supplies cannot be turned on and off when the source of the supply is not available.

What is needed is a way of distributing renewable energy from intermittent sources in a way that can reduce or remove the intermittency factor.

Prophetic visions abound about possibilities such as global intermittent energy collection devices with energy transported around the globe as electricity on a global grid network. Daylight supplying night time areas and vice-versa with increased nigh time wind supplies. DC current replacing the problematic nature of transporting AC current over large distances. Huge global energy ‘granaries’ of harvested energy stored in batteries or as vast underground caverns of compressed air operating power station generators during peak energy demands.

In reality, and away from imaginations that are perhaps too futuristic for present immediacy, the solution to renewable energy intermittency is probably already well under development.

Energy obtained from intermittent sources can be easily and efficiently converted into hydrogen and stored under pressure as a liquid.

Hydrogen is a very clean fuel, simply converting back into oxygen and water when it is burned to release its energy.

Transporting energy as a liquid or a gas along pipe networks is a highly efficient method of moving energy across distances. There is little loss of energy, unlike the horrendous losses on electrical grid supplies.

What is more, experiments in America have concluded that mixing small amounts of hydrogen gas in with the methane gas supplying domestic and industrial usage causes no problems with appliance operation. Eventually, all appliances could be converted to run on hydrogen, even vehicles.

Surely, gas from wind power has to be the most feasible means of dealing with renewable energy intermittency. Producing hydrogen gas and circulating it through established gas networks supplying domestic users, industry and local electrical power generating stations, must be an attractive solution.

Although the exploration and extraction of shale gas may go towards supplementing and securing gas supplies in the UK, any further developments in storing intermittent renewable energy production will very likely continue to progress along hydrogen production and storage techniques to continue the UK’s utilisation of gases as a fuel source.


Alternatives to Copper Pipe for Central Heating Installations

A few weeks ago, when I was considering installing a wet central heating system in a property I had bought to let, I asked our local plumber to quote a price. Once I had recovered from the shock, I asked him whether such a vast amount of expensive copper piping was actually necessary. Was there not an alternative?

“Copper’s proper” was his affronted response.

This quite naturally got me thinking about the alternatives to using copper in such circumstances. I was quite aware that such products existed and were often used, although my direct experience had been limited to the use of UPVC plastics for wastewater disposal.

I had also once taken a camping holiday with the family where the site water supply was routed to stand pipes through black alkathene tubing. I can distinctly remember the unpleasant after taste associated with not allowing the water to run for an appreciable time before collecting it.

In the past, plastics and their derivatives have come under much scrutiny, particularly where contact with them via food and drink has raised doubts about their safety.  Phthalates and other toxic components in PVC type products are known to migrate into materials that come into contact with them. Fears about the carcinogenic nature of the chemicals required for the manufacture of such plastics have raised doubts about their safety and the long term effects of the products on the environment has become a sensitive issue.

But potable water for drinking is a different consideration to that of wet central heating fluids and although I can understand that certain plastics may under some conditions release toxic materials into the atmosphere, I am sure that there must be alternatives to copper that are suitable for domestic heating use.

PVC, I discovered, is not suitable for use with hot water so that has to be ruled out.

Galvanised pipe, a zinc coated steel or iron pipe, requires so much cutting and threading that combined with its price, the cost of labour for installation could make it more expensive than copper.

CPVC can withstand temperatures up to 180 degrees and can accommodate push fittings like Sharkbite, making installation a straightforward procedure; however, the use of glues and solvents for some joint fittings tends to ring alarm bells for me in respect of long-term resistance to leaking.

Where CPVC pipe-work has required jointing with solvents and glues, the long-term effectiveness of the joints has become compromised by changes in the molecular structure of the bonding materials. Expansion and contraction of these types of pipe can weaken joint bonds, as can vibration where pipes have not been sufficiently supported.

Some plastic type piping introduced in the past, has been found to develop problems with degradation through exposure to sunlight UV and chemical pollutants in the air. Both rigid and flexible plastic pipes have developed a tendency to become brittle.

There are some plumbers using HEP20 barrier pipe for central heating installations. This type of plastic pipe incorporates a barrier that prevents air from penetrating through the wall of the pipe and entering the water system. This helps to reduce the effect of corrosion upon metal components within the system.  The barrier also acts as a good insulator, preventing heat loss between boiler and radiator. This type of pipe is cheaper than copper, is easy to cut and fit and when installed correctly is quite durable.

XIPEI or PEX as it is generally called is a versatile product often used in domestic plumbing installations. Its acronym stands for Cross-Linked High-Density Polyethylene. The product has been around since the 1970s but is becoming the material of choice in new homes. PEX does not require any glues and solvents, but does require dedicated fittings and special tools for making secure, watertight joints. The material is flexible for ease of installation and can be gently manipulated under floorboards and around corners. Bearing in mind that copper must be used for at least the first meter of piping leaving and returning to the boiler, PEX can be used for pipe lengths that are hidden from sight, coupling to copper or steel fittings above floorboards etc.

The material can be purchased on reels for cutting to required lengths. It is also available in colours suitable for colour coding, which is ideal for differentiating between hot and cold water supplies.

PEX is lightweight and durable, but requires adequate support when fitted. It is also a stable material and can withstand a variety of environmental conditions that could prove problematic for other materials, including copper. As a result, PEX material carries a long guarantee against defects.

Because a number of companies produce products made of PEX, it can be found that fittings and components vary. It is important to ensure that fittings are compatible especially when joining the material.

So. There are materials that can replace copper for central heating installations.

The main problem with copper is the volatile metals markets that can see prices fluctuate alarmingly. Currently copper and other metal prices are high. This volatility makes copper unattractive to some plumbers due to the reduced profit margins that can occur. Plastics, on the other hand are relatively cheap and price-stable making them attractive to plumbers. The speed and efficiency with which they can be installed reduces the cost of installation for plumbers, but not necessarily for the customer.

There can be no doubt that where plumbing has to be visible, copper carries a particularly aesthetic quality that can never be replaced by functional plastic. It is also fair to say that most plumbers will view copper as being the material of quality and artisanship.

Plastics are ideal for DIY where plumbing skills are perhaps limited, but as with all plumbing, ease and efficiency are not necessarily the essence of reliable and durable installations.

However, because I am aware that a copper installation will reflect on the desirability of my buy to let property should I come to sell it, and that my buildings insurance company does not take a positive view when it comes to alternative heating plumbing materials, “copper” certainly seems “proper.”

Weather Compensators

The introduction of gas fired condensing boilers marked a great step forward in significantly reducing domestic gas consumption and improving energy efficiency. The corresponding savings in domestic energy costs has helped to stimulate an increasing awareness of environmental issues, and a growing industry is developing to provide practical solutions to maximise efficiency.

Gas can longer be perceived as an infinite commodity. The need to prolong the availability of fossil fuels in a world of growing demand is quite evident. Such demand and scarcity have created record global prices and forced governments to look closely at their energy supply and security issues.

Home-owners continue to look for devices that can further improve the energy usage and efficiency measures already installed within their own homes.

Where a condensing boiler has been installed, the fitting of a weather compensator can modify the central heating operation to ensure that the benefit obtained from the condensation of flue gases is maximised.

A weather compensator can also improve comfort levels within the home.

Most condensing boilers are able to utilise the weather compensating technology. Some have it fitted as a standard built in part of the boiler construction and complimented by an external sensor.

Weather compensating devices are small, sensing units that are fitted externally, ideally to a north or north-west facing wall. This position is to prevent solar gain from the sun’s east-west and southerly direction affecting the unit’s operation. The weather compensator is wired up to the boiler’s internal controls.

Weather compensators work by monitoring the external temperature. They are in constant communication with the boiler and relay information about the current weather conditions to it.

By monitoring the external temperature, the weather compensator is predicting how the external temperature will affect the internal temperature of the property.

Heat generated by the boiler and distributed through the central heating system gradually dissipates through the walls, windows and roof into the atmosphere. Good quality insulation and draft exclusion measures can reduce the rate at which this heat loss takes place. However, it is this gradual heat loss that necessitates the need for the boiler.

When a drop in room temperature is sensed by the room thermostat or radiator TRV’s, these devices instruct the boiler to operate. However, the boiler’s response is to operate at full capacity until the room temperature rises sufficiently to cause the thermostatic devices to operate again. When the boiler receives the thermostat’s signal that the room’s pre-set temperature has been reached, it turns itself off.

Although this process is very efficient, for a condensing boiler the operation is not as efficient as it could be.

This is because the boiler is responding solely to the internal room temperature. The boiler has to supply hot water until instructed by the thermostat to stop, often operating to give more frequent, short bursts of heat than necessary and overshooting in its attempt to play catch-up when trying to maintain a steady room temperature.

However, the internal room temperature is affected by external environmental conditions. When the weather outside turns cold, the heat loss through the walls is greater. When the walls and other external surfaces are cold, heat dissipates through them much faster.

Conversely, when the external temperature is mild or warm, heat within the property is retained for longer.

In order for a condensing boiler to operate effectively, hot water returning through the central heating system must be below 57 degrees centigrade to allow flue gases to condense efficiently. Efficient condensation allows the latent heat contained within the flue gases to be collected and conserved within the system, rather than being lost.

Hot bursts of energy as a response to thermostatic commands often results in central heating fluid return temperatures too high to allow an effective condensation process to take place.

Weather compensators act as a prediction device warning the boiler that either a falling or a rising temperature will affect the building’s capacity to maintain a predetermined internal temperature.

When the weather starts to turn cold, the weather compensator communicates the rate of lowering temperature through its constant communication with the boiler.

Being, as it were, forewarned, the boiler starts to operate at a lower temperature, earlier than it would by thermostatic control alone. This has the effect of compensating for the slow dissipation of heat from the building.

Conversely, in milder temperatures, the boiler will turn itself off or run at a much lower temperature in response to warmer external temperatures long before the internal thermostats register the drop in heat requirement.

This process causes the boiler to operate at lower temperatures and helps to ensure that the returning central heating fluid is at a temperature below 57 degrees centigrade more frequently than would otherwise be the case. This helps to maximise the condensation heat exchange process.

Although a weather compensator can make boiler operation very efficient, householders may take some time to adjust to the situation of having cool radiators during freezing weather. Most people associate cold weather with having radiators that are too hot to touch. However, the objective of using weather-compensating equipment is to maintain a comfortable and stable internal room temperature.

Hot spots caused by very hot radiators are eliminated, as are sudden peaks and troughs in energy demand.

The weather compensator helps to maintain a steady constant room temperature rather than allowing the boiler and thermostats to continually function by responding to variations in room temperature.

However, getting used to cooler radiators that maintain a good steady room temperature may only be of long-term concern to households who have become accustomed to drying their washing on super-heated radiators.

In the long term, people who fit weather compensators report an improvement in the maintenance of comfort levels within the building and a more than welcome reduction in energy usage and the subsequent cost.

Weather compensators are relatively cheap to fit and once installed and pre-set to user requirements require little or no maintenance. They should be left to work without any consumer interference, other than the operation of an over-ride facility should the need ever arise.

Before investing in the purchase and installation of a weather compensator, the homeowner should consult the boiler user manual for particular specifications. Not all homes will get the full benefits from the installation of a weather compensator.

Drain Cock Not Working or Blocked


You have planned to drain the central heating system. You have turned off the boiler and water supply. The system has cooled down. You have released pressure, particularly if the system is pressurised. You have opened radiator bleed valves. You have located the central heating system drain cock and attached a hosepipe to it to facilitate drainage. You have even secured the hosepipe with a jubilee clip as an added precaution. What could go wrong?

You try to turn the drain cock spindle with an adjustable spanner. But it will not move.

So what can you do?

Well, depending on the time of year and the location of the drain cock there could be a possibility that it is frozen. Central heating drain cocks are often located outside for a variety of reasons; one being that central heating fluid can permanently stain any material it comes into contact with. Installing a drain cock outside the house prevents that problem, but without adequate insulation renders it liable to freezing, and even splitting in severe frosts. A frozen drain cock can be freed by applying a heat source.

All drain cocks are prone to seizing due to infrequency of operation.

If the drain cock is located internally, the application of a releasing fluid, such as WD40 could free a seized mechanism. It may take a few minutes for the fluid to penetrate sufficiently to be effective. Take care when trying to turn a stubborn spindle, it can snap off.

Another big danger in trying to turn a seized drain cock spindle with grips, or an unsuitable spanner, is the sheering away of the square spindle top. Often drain cocks are situated in areas where there is little room to manoeuvre spanners and grips. Once sheered, the drain cock becomes almost impossible to operate compounding the problem. It is possible to purchase a dedicated tool, which is ideal for opening and closing drain cocks in awkward places.

Sometimes a drain cock spindle will appear to turn freely, but no central heating fluid flows out of the system. Assuming that radiator bleed valves are open and that no internal vacuum is preventing fluid from flowing, it is probable that the drain cock is blocked. This can be caused by a build up of sludge blocking the drain cock, or the detachment of the drain cock washer from the spindle. Occasionally, the washer can adhere to its seating in the valve, particularly if it has been over-tightened and can detach from the spindle when it is operated.

It is not unheard of for an incompetent plumber to melt the washer, sealing it in the closed position when soldering a new drain cock onto pipe-work. Of course, this only comes to light at a later date when it becomes necessary to operate the drain cock.

Where sediment is suspected of causing a restriction to flow through a drain cock, it may be possible to clear the blockage by delivering a reverse flow of water into the system through the hosepipe attached to a mains supply and onto the drain cock. This should be done in short bursts, removing the hosepipe from the mains tap each time to check whether flow has started.

Where a detached washer is suspected, it is possible to insert a screwdriver into the drain cock outlet and attempt to dislodge the washer. Of course, precautions must be taken to accommodate a sudden flow of central heating fluid, which will occur once the washer is dislodged. Plenty of towels and absorbent material will soak up fluid spillage whilst a hosepipe is hurriedly attached to the drain cock spout.

Naturally, the system cannot be refilled until a new washer is fitted or the old drain cock is removed and a new one fitted. Fitting a new washer is a simple task as long as a suitable replacement is sourced. Stripping down the drain cock is a simple procedure. A new washer can be pushed onto the jumper and the body re-assembled. Always take the old washer along to suppliers to get an identical match. Washers should be replaced after several years to prevent fluid dripping due to deterioration.

Where there is a sufficient leg of pipe-work leading to a seized drain cock, it is possible to drain a central heating system by installing a temporary self-cutting drain off tap or a self cutting washing machine valve. However, it would be best to remove these and fit a new piece of pipe with a functioning drain cock prior to re-filling the system.

Where no drain cock can be found, it is possible to drain a central heating system by finding the lowest and smallest radiator in the system. Find the plug usually located at the top of the radiator. Turn off the wheel head and lock shield valves. It is then possible to remove the plug and by inserting a half-inch fitting, attach a hosepipe to the end of it. Opening the wheel head and lock shield valves will allow most of the central heating fluid to be drained. The remaining fluid can be drained by detaching the radiator at the bottom return flow and catching the fluid in a suitably sized container. Where possible this method should be avoided and only used as a last resort due to the inevitable large quantity of central heating fluid spillage.

Many problems with drain cock operation can be prevented by frequent operation and adequate insulation against frost. This applies to drain cocks fitted to any domestic system. Never over tighten a drain cock.





Remote Heating Controls

Imagine the situation. It’s mid January and you are enjoying a spot of snorkeling off the Great Barrier Reef. Then, as you haul yourself into the inflatable, out of the blue you get a text from your daughter saying that she has had a row with her partner and is moving back into the family home, “like, now.

Although the house back in Blighty has been empty for a couple of weeks, the heating has been ticking over to keep the property frost-free.

Still, it is not going to be a very warm and inviting environment for the imminent return of a daddy’s little angel.

No problem, you simply head back to the yacht, log onto the internet and adjust the heating settings via the Wi Fi hub back at home. Then you text your daughter telling her to make herself comfortable and that you will be back as soon as you can get a flight.


Although the scenario might be a little OTT, the practicalities of controlling your domestic heating controls remotely are not. Having discovered that householders might wish to monitor and adjust their home environment from another location, or at least suggest to them that it might be a good idea to, a number of companies are now actively promoting the technology.

British Gas is at the forefront with Hive Active Heating. It is believed that this company has over 50,000 homes across the UK using their system.

Following its purchase of Nest, Google are trying to become a major competitor to British Gas in the UK remote heating control market. Although very successful in the US, some feel that Google’s business model, dependent on collecting personal data, may deter many households in the UK from considering their product. To try to overcome this negative perception, the company has formed a marketing partnership with N.power.

Honeywell, who have long been associated with heating control systems, have their own multi room system on the market.

Also venturing into the UK market is Tado, a successful German company who like to stress their independence from the monitoring suspicions and capabilities of other players in the market.

There are of course other systems available, usually aimed at the dedicated technophiles who like to indulge in creating distinctly personalised systems. These often Heath Robinson configurations of hardware and software probably incorporate considerably more functions than the mass-market products. They are, however, often very sophisticated and subsequently prone to some unexpected behaviour, much to the delight of their assemblers.

Although the major players in the remote heating control market offer pretty much the same technology and features, Hive Active Heating from British Gas is currently the most popular system. Priced at £199 including fitting, it compares favourably against Google’s Nest at £249.

What is more, you do not need to be a British Gas fuel customer to obtain the system; however, there are instances where British Gas might install Hive for its boiler-servicing customers at a more favourable rate. This can sometimes occur in situations where existing boiler controls are faulty.

It is a good idea when choosing a remote control heating system to establish whether the intended system is suitable for your requirements and has functions to control heating and hot water, as some systems are only able to control heating.

So. The first requirement of any current remote access heating system is a broadband internet connection. The broadband router will need to have a spare Ethernet port.

Taking the Hive system as an example, a British Gas engineer will take approximately ninety minutes to install the components.

The engineer will disconnect any existing wired connections from the boiler to the thermostat and connect a wireless receiver to the boiler.

A wall-mounted programmer will be installed in a suitable location.

A dedicated system hub will be plugged into a spare Ethernet port on the broadband router and connected to an electrical supply.

And that is it, although the engineer will demonstrate how to use the system and get it up and running.

The boiler must be set to constantly on at its independent settings to allow the wall programmer to take control over it.

The system can now be operated by either accessing the British Gas website on a PC or Mac, by installing an application on a smart phone or tablet, or by sending a text to the SIM card that is installed into the wall-mounted programmer. This latter option is a useful standby in situations where internet access is temporarily unavailable. The system obligingly sends a return text in acknowledgment. The boiler can still be operated normally by manually adjusting the wall-mounted programmer.

So. What are the advantages?

Well, manufacturer’s claim that users are able to reduce their energy consumption and consequently save money. They suggest that being able to control the heating remotely allows more focused and targeted heating manipulations to fine-tune requirements. This has the advantage over conventional seven-day programme modules of being able to respond to unexpected situations.

The interface also displays usage and trending information.

If you are already in the market to upgrade your heating controls, getting a remote control system installed by British Gas or Nest can be a cheaper option.

With the British Gas system being operated from the company website, users are able to access their energy accounts if they are fuel customers.

It is also suggested that these devices are the harbinger of far more sophisticated systems that will one day control many aspects of home management and daily life.

However, possibly the greatest benefit from these remote control systems is that in the home, the user will no longer need to get up from the armchair to adjust the heating.