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.

 

 

How to Repair the Main Stopcock

The house stopcock, or shut off valve, controls the mains flow of cold potable water into the property. It is commonly located under the kitchen sink although it may also be installed near a front door, in a cupboard, or even under a floorboard. It would be uncommon to find more than one stopcock controlling the mains water supply into an individual property.

Most stopcocks have to be manually operated, although there are now some being installed that are electronically operated. Electronically controlled stopcocks require specialist maintenance and should not be serviced by the householder.

It is most important that the householders are able to locate, identify and operate the manual stopcock. This is because it is the most practical way of closing off the pressurised mains water supply into the property. This would need to be carried out quickly in the event of a water leak or burst pipe within the property. It might also need to be operated to facilitate water appliance repairs or installations.

Perhaps the biggest problem that occurs with mains water supply stopcocks is the inability to turn them off. This is due to infrequent use. Without a frequent operation, the internal mechanism becomes affected by mineral particles and substances produced by the effects of metal corrosion. These adhere to the surfaces of the moving parts. Over time, this causes the washer and jumper mechanism to seize up. The crutch head becomes very difficult, if not impossible to turn. In the panic of a plumbing emergency, it is not uncommon for a householder to apply excessive force to the crutch head of a seized stopcock. Unfortunately, this can result in the crutch head shearing off from the spindle, leaving the valve in the open position.

It is also important to ensure that the operative knows which direction of turn opens and closes the stopcock. It is not unusual to find a householder has sheared off the crutch head by applying excessive force in the wrong direction.

Anti-clockwise opens. Clockwise closes.

To prevent problems occurring with a stopcock, it is a good idea to turn it on and off regularly. This will help to prevent a build up of material and ensure that the mechanism operates freely. It is also a good idea to turn a freely operating stopcock fully on, and then give it a half turn clockwise and leave it at that position. This will provide a little extra play on the device should it become stiff to operate in the future.

To free a seized or difficult to operate stopcock, spray a little penetrating and lubricating oil onto the spindle and gland nut, and then leave it to seep into the mechanism. This should solve the problem. If that does not work, slacken the gland nut and apply the spray again. If the stopcock still refuses to operate, a small amount of force can be applied to the crutch head using a wrench.

Occasionally, applying a carefully directed blowtorch flame to the gland nut will provide just enough metal expansion to free the seized mechanism. It is a wise precaution to clean away any surplus penetrating oil before doing so.

If all attempts to free a seized stopcock fail, the water supply can be turned off at the water supplier’s main valve. This will usually be located outside the homeowner’s boundary. It may be on the pavement under a small iron cover marked SVS, or it may have the water suppliers identifying mark. Sometimes this valve is a normal stopcock, but more often than not it is a spindle headed valve that requires a specific tool to operate it. This can be obtained from tool hire firms.

Alternatively, the water supplier will attend to operate the device. This mains stopcock is the property of the water supplier and its maintenance and operation are technically their responsibility.

On some networks, turning off the water supplier’s mains water valve will affect other residents. They should be forewarned about any interruption to their supplies.

Turning off the water supplier’s mains supply valve will facilitate the repair or replacement of the domestic water stopcock. It is quite feasible for a competent DIY enthusiast to strip down and service a mains stopcock or to remove and install a new one. However, the location of the stopcock may make access and work on it difficult due to restricted working space.

When removing and replacing a domestic mains stopcock, there will be a significant amount of water and pressure remaining in the system when the supplier’s valve has been turned off. This pressure can be released by turning on the domestic cold-water tap. Unless a drain valve has been installed close to the stopcock, a suitable receptacle will be required to collect any surplus water draining from the pipe above the stopcock.

On other occasions, a householder may become aware of a slow leak from a stopcock. Left unattended, a small leak can cause substantial damage to the fabric of a property. The most usual causes are leaking compression nuts or deterioration of the gland packing material.

Leaks from the compression nuts can be addressed by gently tightening the nuts. Care should be taken to not over-tighten compression nuts, as this will interfere with the correct operation of the stopcock. The stopcock should be held firmly with a set of grips whilst tightening the compression nuts to prevent fracturing the attached pipe-work.

Leaks from the gland head can be rectified by trying to tighten the gland nut. If that fails to stop the leak, removing the crutch and unscrewing the gland will allow the householder to clean away any detritus and old packing material. It is not necessary to turn off the water supplier’s main valve to accomplish this task. PTFE tape can then be gently wound around the exposed area of the spindle and prodded down into the gland area with a screwdriver. The gland nut and spindle can then be re-attached.

In general, the regular inspection and operation of the domestic mains stopcock will ensure problems do not occur, or only become apparent in an emergency.

Because of the substantial damage that can be caused by unmanageable releases of water under mains pressure and the subsequent insurance implications, if there is any doubt over issues relating to competency, professional assistance should be sought in relation to stopcock operating issues.

Combi Boiler Pressure Checks

Gas combination condensing boilers, better known as combi boilers, are highly efficient water heaters. They are compact fuel misers, designed and installed to extract the maximum heat from their fuel source.

Unlike their open vented counterparts, combi’s are designed to run a pressurised hot water central heating system that eliminates the need for feed and expansion tanks. This attribute is most advantageous in a property where available space is limited.

Like any sophisticated appliance, combi boilers respond well to good and regular attention. Annual maintenance and servicing by suitably qualified engineers will help to keep a combi in good operating condition. This provides peace of mind for a homeowner in knowing that the boiler is performing in line with requirements and unlikely to break down in the depths of winter.

However, combi boilers require another simple check that can be carried out by the homeowner. Checking that the combi boiler operating pressure is correct and undertaking the necessary operations to maintain it is a relatively easy task.

A combi boiler pressure check should be carried out once a month on a correctly functioning boiler.

The pressure within the central heating system is registered on an analogue dial or digital display panel. In most modern combi boilers, the dial or display is located on the boiler. This can be either on the front, sometimes beneath a protective flap, or at the base, but not always immediately visible due to the boiler cover. It is not usually necessary to remove the boiler cover to observe the pressure register.

Very occasionally, the pressure registering display device is located separately from the boiler but is generally in the vicinity of it.

To locate and correctly identify the pressure gauge, the homeowner should refer to the combi boiler instruction manual.

Having located the pressure-registering device the current pressure within the system can be ascertained. A normal pressure range will be between 1 and 2 bar. On an analogue gauge, a black needle will indicate the pressure on the numbered dial face. On some models, the acceptable cold working pressure area will appear as a green coloured fraction on the dial face. Occasionally a further red needle will be present. This is adjustable and can be set to indicate the optimum operating position that conforms to the manufacturer’s recommendations.

As operating pressures may vary between manufacturers and boiler models, the manufacturer’s instruction manual should be consulted to establish the correct pressure ranges.

Where a boiler appears to be operating at a lower pressure than recommended, the system will require pressurising.

To pressurise a combi boiler central heating system, a filling loop is usually provided as part of the installation. The loop consists of a short length of flexible metal or plastic tubing. This will have screw fittings at each end. There should also be valves at either end of the loop. These may be of a lever or screwdriver operated type.

Before commencing to pressurise the system, the gas burner on the boiler should be turned off. It is probably easier to work on a cold boiler and central heating system.

With the loop valves in the closed position, one end of the loop must be screwed onto cold-water input branch feed beneath the boiler. The other end should be attached to the cold-water branch from the mains cold feed. Both these feed points will have flow control valves.

With the loop securely attached, the loop valves can be opened. The mains water branch feed valve can also be opened. To commence pressurisation, the cold mains inlet feed valve should be carefully operated. The sound of water entering the boiler should be heard.

Whilst observing the boiler pressure indicator gauge or digital display, the valve should be kept open until the correct pressure has been achieved and registers on the display.

Once the correct pressure has been reached, the valves on the loop and the two feed pipes should be turned off.

The filling loop can then be disconnected and the boiler operated. It is not good practice to leave a filling loop permanently attached to a combi boiler.

On some combi boilers, a filling loop is not required and the boiler has an internal pressurising system. This is operated by a dedicated key that has to be inserted into the base of the boiler. The key locks into an internal pipework mechanism and turning it operates the pressurising system. The pressure gauge must still be monitored. When the correct pressure is achieved, the key can be unlocked and removed.

On some boilers, instructions on pressurising are displayed on the boiler. However, the best practice is to consult the operator’s manual where detailed instructions for pressurising the specific boiler model will be found.

After pressurising, the central heating radiators may require bleeding. After bleeding the radiators, the pressure gauge should be re-checked, as it is often necessary to add a little more pressure into the system.

If, when attempting to pressurise a combi, the pressure cannot be raised, immediately check the entire system for evidence of a possible leak. Another cause of not being able to pressurise the system is an inadequate mains water pressure. This may be caused by maintenance operations or burst pipes on the mains network. Often, when the mains pressure is low, the boiler will not function by design.

Where a combi boiler loses pressure frequently, a fault may lie within the central heating system or the boiler itself. If, after checking the system for leaks and checking the boiler’s pressure release valve for faulty operation no problems are evident, it may be necessary to employ the services of a qualified engineer.

Significant problems can often occur when a combi boiler is installed to replace a conventional boiler. The pressure produced by a combi boiler may cause problems in an older central heating system. It is important to have the old system professionally pressure checked prior to installing a combi boiler.

When properly maintained and cared for, a combi boiler will continue to work efficiently and reliably for many years.

 

 

Pressure Booster Pumps

Low water pressure, as an infrequent event caused by your water supplier carrying out maintenance on its mains network, or as the result of a burst mains at a distant location, it is something that cannot be avoided.

However, when it occurs frequently, often at certain times of the day, or when it is a constant problem, it can be a major issue. Showers and boilers, which require a minimum pressure to operate for safety reasons, will often not work.

Constant or inconvenient low water pressure can have numerous causes. It is a good idea to try to establish the cause before going to the expense of purchasing and installing equipment to boost domestic water pressure. Adding extra pressure to a damaged or partially blocked domestic water network may cause damage to the pump and plumbing.

Is the low water pressure limited to the domestic hot water supply or a problem concerning the entire water supply?

Where domestic hot water is supplied by a cold tank gravity fed system, a suitable head of pressure needs to be present to force water through the system. If the cold water storage tank is not at a suitable height, for example in a single storey house, the pressure may be low or at an unacceptable level.

If this is the case, a suitable water pump fitted into the hot water supply line at the exit point from the hot water cylinder will pump water on demand and at a suitable pressure to outlets.

It is important to ensure that the cold water header tank has an adequate capacity to feed the hot water storage cylinder when the pump operates and starts to empty it. Insufficient capacity may allow air to be drawn into the system.

For combi and sealed boiler systems and for general mains cold water, it is important to ensure that a low water pressure problem is not being caused by a leak. This could occur either within the boundary of your own property or that of any other property that is supplied by the service pipe.

It is also a good idea to check that your mains stop cock is turned fully on. It is not unusual to find pressure and flow problems caused by a stiff valve that a previous user failed to open fully.

The water company that serves your community will be able to determine whether low water pressure is the result of a leak or simply due to local demand on their side of the supply line.

Water supply companies sometimes minimise pressure within a local network to avoid causing damage to their already deteriorating systems.

Where a water company reports that water pressure and flow rates are within expected tolerances within its own mains network up to your boundary, the next step is to ensure that the problem is not being caused by other issues in the domestic network.

Over time, domestic pipe-work can become clogged up with encrustations of sediments and deposits that may be impossible to clear. If this is the case, re-piping is the only solution.

Occasionally, where lead and exposed copper piping remains in older buildings, the pipe-work can become accidentally crushed, restricting the flow around the property.

Sometimes following an investigation be the water supplier, it can be established that a low water pressure issue is not one that can be remedied by them. Perhaps your property is situated on a hill or low pressure is just an accepted inconvenience in your particular area,

If this is the case then a domestic pressure booster water pump could be considered as an option for increasing your water pressure.

There are a considerable number of manufacturers of pressure booster pumps and many different designs.

You should carefully establish that any pump you purchase is capable of supplying the required pressure. It is also important to consider where the pump will be located. It will need to be installed on the mains cold water pipe-work close to the stopcock but before any appliance.

When installing, it will require an appropriate electrical supply and an isolating valve on the pumped water flow line to enable future servicing.

Many booster pumps incorporate into their housing or require a pressure and expansion device. These devices prevent damage to the pipework system or attached appliances in the event of an excess pressure problem.

Bearing these points in mind, the size of the pump is going to be an important consideration to ensure that it, and its necessary fittings, will fit into the desired area.

Pressure booster pumps are designed to maintain a minimum pressure within the system and to operate automatically when they detect a drop in pressure caused by a demand. They then continue operating until the demand discontinues and a cutoff pressure is reached.

Most pumps operate quietly. When installing the pump consideration should be given to the surface upon which the pump is secured to minimise amplification of noise caused by vibration.

The actual plumbing of a pressure booster pump is an easy task. It is simply a matter of making an appropriate cut into the existing mains water pipework and attaching the pump inlet and outlet connections. If extra connections are required to accommodate expansion and pressure release mechanisms these are usually straightforward procedures.

If you are considering undertaking the work yourself, then pumps are readily available and installation instructions are usually quite comprehensive and easy to follow.

As with all DIY tasks, care should be taken to ensure that any work undertaken is within the capabilities of the person undertaking it. Poor workmanship can be expensive to correct. It is also wise to consider household insurance issues that may arise due to water damage caused by non-professionally installed appliances and subsequent plumbing failures.

 

 

 

 

Boiler Fittings and Mountings

The fittings and mountings for domestic boilers are usually dedicated to specific boiler types and individual manufacturer’s boiler models, and as such are produced by the manufacturer and provided with the boiler and the installation package.

Domestic boilers include oil, wood, coal and electric fuel sources and a wide range of different models are available to choose from when considering which type of heating boiler is to be installed.

Coal or wood-fired back boilers are often found in old properties and it is very simple to remove a damaged boiler and plumb in a new one. Fittings are generally plumbing standard.

Oil fired boilers require an external large capacity oil storage tank, and the are usually floor standing. Plumbing and fitting components are generally plumbing standard, however, the boilers are often heavy and large. There are wall mounted oil fired boilers available and these are normally installed externally.

Both these types of boilers can be installed by any person with an adequate knowledge of plumbing and heating techniques, although where electrical installations are complimentary to the system, these should be installed by competent electricians.

Electric heating boilers are usually positioned discretely out of sight, although some which provide only domestic hot water on demand can be wall mounted at the point of use. The mountings should be secure, but as these units are quite light, they do not require the same weight-bearing considerations as those of complex gas condensing boilers.

Because combustion is not a process utilised by electric boilers, neither a flue nor a ventilation requirement is necessary. These boilers can run central heating systems but are considerably more expensive to operate than their gas-burning alternatives. These boilers do require basic plumbing installation techniques.

Electric boilers do not require local authority notification and can be installed by a competent electrician.

Gas boilers are a different matter. Most new gas boilers are wall mounted condensing boilers and although they can be located discretely, they require careful consideration when choosing a location.

For the purpose of flue ventilation, they require an external access point and are usually installed on the inside of an external wall.

The location of the exhaust gas flue is subject to restrictions to prevent nuisance to neighbours and to prevent any possibility of flue gasses re-entering the building. It is possible to locate a boiler externally, subject to the manufacturer’s recommendations.

The boiler installation must comply with BS 5410 and the Building Regulations Part 2. 1997.

From 1 April 2009, it is a legal requirement that gas boilers can only be fitted by a ‘Gas Safe’ registered installer.

The wall upon which the boiler is to be mounted must be surface flat and capable of supporting the weight of the appliance when it is operating full of water. This can be in excess of 100 kg with larger boilers.

The boiler will come with a dedicated template to allow markings of mounting bracket locations to be transferred to the wall. It is essential to ensure that the template is level before proceeding to mark or drill and that the position chosen allows extra area above the boiler for the installation of the flue. The template may also provide markings for a gas and water connection plate. These should also be transferred to the wall. The bracket, when fixed, must take account of the boilers clearance requirements as stated in the installation instructions.

The bracket must be attached to the wall with anchor bolts that are suitable for the wall’s construction material and the weight of the boiler.

Once the gas and water connection plate has been attached to the wall, the water and gas can be connected to the plate. The connections are standard starting left to right: heating supply, domestic hot water, gas, cold water and heating return. The manufacturer’s instructions will clearly indicate which service is required to each connection point.

When attaching the boiler to the gas supply, the correct fittings must be installed to prevent any unwanted drop in gas pressure.

A connection plate allows other trades to complete installation procedures prior to the hanging of the boiler onto the mounting bracket and final connection of the boiler.

In the absence of a connection plate, the plumbing can be made straight to the boiler directly.

Plumbing and pipe-work will be dependent on the system the boiler is designed to supply.

It is also a wise precaution to install service valves to the pipe-work to aid future service and maintenance procedures.

A drain, or the access to one, is also a requirement to accommodate pressure release valves and condensate drainage.

The positioning and installation of flue gas and air intake pipework should be in accordance with manufacturer’s instructions. Some of the components for this may not be included in the boiler installation kit. This is because variations in the flue gas assembly are dependent upon legal requirements, location, and circumstances and are generally constructed to individual requirement.

The electronics are usually the final connections to be made to the boiler. These will include room thermostats and system programmers. Other sensors may require additional connections, including mains water supply sensors and low water cut-off sensors.

Finally, the boiler can be attached to the mains electricity supply which will power all the electrical components and the boiler can be commissioned.

The connections of the electronic components and the connection to the mains supply require the skills of a competent electrician.

Replacing a Boiler Expansion Vessel

Before considering the repair, replacement or modification of any parts on a boiler, it is a wise precaution to check warranties, service and maintenance contracts and insurance policies to establish whether the work is covered by them, sometimes contrary to an engineer’s advice.

Also, consider whether any repairs carried out on parts that are not covered by warranties might invalidate the warranties if performed by engineers or companies other than those that may be specified by the contracts.

Combi boilers operate using a sealed or pressurised system. Because water expands when heated, an expansion area must be incorporated into the heating system. On a combi boiler, this is usually encased within the boiler housing. It comprises of a vessel with an internal area divided by a flexible membrane. On one side of the membrane is compressed air. On the other side is the central heating fluid. The expansion vessel has a Schrader valve on the air-side where air can be pumped into that part of the vessel to maintain a suitable resistance to the water expansion. This maintenance pressure is usually around 1 bar.

When the heated water in the central heating system expands, it cannot be compressed and consequently presses against the expansion vessel’s internal membrane. This flexible membrane, in turn, distorts to apply a corresponding force on the encased air on the opposite side of the vessel. As air can be easily compressed, the air takes up the expansion volume of the hot water preventing unwanted and dangerous expansion in the heating system.

The expansion vessel in a combi boiler is generally fitted to the central heating return section within the boiler housing. The main problem with expansion vessels is that over time, the diaphragm can deform or even split.

The usual indication of problems with an expansion bottle is a rise in operating pressure registering on the boiler pressure gauge when the heating is operating. A continual increase in pressure will cause the pressure release valve to operate. This will totally remove pressure from the system and consequently, the boiler will most likely shut down. The system will then need to be refilled.

It is a wise precaution to check that the fault with pressure does not lie with a faulty pressure release valve.

Very occasionally, a loss in operating pressure is due to a damaged heat exchanger. If there is any doubt about what might be causing a loss in operating pressure, professional advice should be obtained.

When working on a boiler, the appliance must be disconnected from the electricity supply.

To check an expansion vessel locate the Shrader valve and depress the inner spindle with a pointed object. If water drips out, then the internal diaphragm has probably either perished or ruptured and is consequently defunct.

If only a faint hiss of air or nothing at all is expelled, then it may be that the compressed air side of the diaphragm has lost its pressure charge. The vessel can be recharged using any form of an air pump and attachment. It should be recharged to 1 bar. It is important to reduce pressure in the central heating system prior to attempting to recharge a vessel via the Shrader valve. It would be wise to check the Shrader valve after recharging by putting some washing up liquid on the valve end and checking for bubbles. If all is well, the problem will very likely be solved. However, if the diaphragm has become too distorted by the vessel having an inadequate air pressure, the capacity for expansion may have been reduced significantly and the heating system will operate inefficiently.

Where a ruptured or inefficient vessel has been identified, there are two choices. Either replace the vessel in the combi boiler or fit an external expansion vessel on the heating return pipe as close to the boiler as is practical.

Fitting a new internal expansion vessel into a boiler is quite an expensive business. It can be time-consuming and should be done by a Gas Safe registered engineer. This is because complex system parts of the combi boiler may have to be removed to access the vessel and sometimes the boiler will need to be removed from the wall. This involves disconnecting the flue, which can pose difficulties when refitting the boiler.

On the other hand, fitting an external expansion vessel as an alternative is a relatively simple procedure. As a Do-It-Yourself task, it is quite inexpensive and can be done relatively quickly with the minimum of disruption.

External expansion vessels can be purchased fairly cheaply, generally for around £40 depending upon the required capacity. This capacity should be established prior to purchase. The information can be obtained from the boiler manufacturer’s handbook relating to the operating capacity of the central heating system.

External expansion vessels are usually pre-charged on the air pressure side of the appliance and simply need fitting into the system. Couplings and copper pipework will be required to enable the vessel to be plumbed into the 15 mm central heating hot water return pipe.

The external expansion vessel should be securely wall mounted and plumbed as near to the boiler as possible, but due to its large size, should also be installed in a practical and unobtrusive place away from any risk of causing obstruction or injury to householders and damage to the vessel.

The central heating system will need to be drained prior to installation.

The new external expansion vessel should be plumbed into the system in such a fashion that it cannot be isolated from the heating side. It must always be an integral part of the system.

Once fitted, the system can be re-filled and operated normally. Do not forget to add inhibitor when re-filling the system. Also, check for leaks and airlocks.

The damaged and non-operational expansion vessel is left in-situ in the combi boiler and will not impede the normal operation of the boiler and system.

If the pressure relief valve has been operating prior to the installation of a new expansion vessel, it is probably wise to replace the valve.

Boiler Emissions

Unless you have direct access to a renewable energy source or nuclear power then the chances are you are going to have to rely on a supply of fossil fuel to heat your home. Your electricity might be ultra clean at the point of using it, but most of its generation, some distance away, will have depended upon the combustion of a fossil fuel, and by the time you get to use it a great proportion of the energy used to create and distribute it will have been lost. In the great scheme of things, electricity generation and distribution is a rather inefficient process.

If your central heating system is powered by a fossil fuel, or for that matter any combustible fuel, then you are going to have to employ the process of combustion to release the energy from the fuel to distribute around your home.

Whichever way you look at it, combustion requires a gas and a heat source. It does not matter what material the combustible fuel is, it will only burn as a gas. It also requires another gas, oxygen which is a component of air to complete the process.

If your central heating is powered by coal or oil, then you are going to have to provide a substantial amount of heat to generate and maintain the release of a gas from the fuel source to facilitate combustion. The purpose of the boiler is to burn the hydrogen in the fuel with oxygen from the air to produce heat.

For a boiler running on gas, the process of having to create a gas is eliminated, although, with bottled gas, the fuel is a liquid under pressure, which is allowed to boil at normal air pressure to revert to its gaseous state.

This is one of the reasons why a gas boiler is extremely efficient. The flammable gas being utilised as a fuel simply requires a source of ignition. A pilot light or a spark will generate a heat source of around 1500 degrees Fahrenheit, which is in excess of the 1100 degrees Fahrenheit required to ignite the fuel.

The other component in the combustion process is oxygen, which makes up about one-fifth of the composition of air.

Combustion will provide the energy you require to heat the water and the by-products of the process are vented through a flue.

It is the availability of oxygen, which is the crucial factor in the combustion process because inadequate combustion will produce emissions other than carbon dioxide (and water). These extra by-products of incomplete combustion can be particularly noxious. Incomplete combustion also significantly reduces the efficiency of the boiler.

A combustion efficiency analysis is an effective way of determining how efficiently a boiler’s combustion process is operating. By knowing the chemical composition of the fuel and measuring the flue gas temperature and either the oxygen or the carbon dioxide levels in the flue vent, the boiler efficiency can be calculated.

The flue gases and temperature are taken with an electronic analysing device pre-programmed to undertake the required calculations. The probe of the device is inserted into the flue area of the boiler in accordance with the boiler manufacturer’s instructions. The post-combustion gases and temperature are analysed and a digital readout is produced. Some analysers allow a hard copy printout to be produced directly. Most boilers are capable of a combustion adjustment operation to improve combustion where an analysis reveals an inadequacy.

It would be impractical to expect to achieve perfect combustion where oxygen levels in the flue gave a reading of zero and flue gas temperature was very low. There are too many variable factors that can influence combustion. However should the combustion process become affected by too little oxygen, the process can become fuel rich and this can cause excess production of carbon monoxide and a possibility that unburned gas could cause an explosion outside the combustion chamber.

An acceptable oxygen reading in the flue should be between three and five percent.

There are other by-products of combustion that can cause problems. Oxides of nitrogen and sulphur can be problematic, as can the particles of soot and other unburned hydrocarbons. These should be minimised by adopting a comprehensive programme of boiler maintenance and regular testing.

Adequate flue ventilation is vital and consideration has to be undertaken when deciding where to position a flue to prevent the by-products of combustion re-entering the home or adjoining properties.

Modern condensing boilers produce another emission. Condensing hot gases and water vapour produce an acidic solution which must be drained into an external drainage facility. Because of its acidic composition, ensuring that the drain connects with the waste domestic or surface water drainage system will dilute the acid and reduce the potential for corrosion.

With older gas boilers and unvented gas appliances, it is important to ensure that an adequate supply of air is available to provide good combustion and also facilitate a good flow of air through the property to remove by-products of combustion such as carbon dioxide, carbon monoxide and of course, condensation forming water vapour.

Gas boilers should burn gas to produce a crisp blue and very hot flame. This can only be achieved by monitoring and good maintenance. Fine-tuning will ensure that boiler emissions are kept within legal and acceptable tolerances, safe operation is maintained and that energy is consumed in a highly efficient manner.

Remote Diagnostic Boilers

Imagine getting a phone call from your gas supplier informing you that your boiler has been talking to them.

Your boiler has advised them that although it is working satisfactorily at the moment, it is, nonetheless, in imminent danger of a catastrophic breakdown. Consequently, they need to send their engineer around to replace a part. The boiler has informed them which part it requires and they just need to arrange a convenient time to pop round and fit it.

Now. Does that increase your comfort level, or reduce it?

Of course, the self-diagnostic capability of appliances and machinery is nothing new. You probably encounter it when you take your car for a service and the garage simply connects your vehicle to a laptop computer. From this, they can detect most faults and also ensure that the mechanics and electrics are all running efficiently.

If you have a modern, top of the range domestic gas boiler you may well have seen a gas engineer carrying out a similar process.

The boiler’s ability to interact with technology is nothing new. Boilers, sensors, programmers and timers have all been interacting together in the home for many years. The practice of remotely communicating with the domestic boiler has already become well established. A growing number of householders are controlling their heating via smartphone and android gadgets. These devices utilise broadband technology to monitor and adjust boiler function and household temperature settings from almost anywhere in the world. Not surprisingly, adjustments to the householder’s heating controls are now often made from an armchair in the home and sent over a few thousand miles of networks and satellite connections to a receiver a few feet away.

But this next step forward in communication with a remote central monitoring facility, which can be hundreds of miles away, is already past the development stage and being trialled by one major energy supplier.

Remote Appliance Diagnostics Systems or RADS for short are being heralded as the next great innovation to revolutionise boiler operation for householders. Offering a sophisticated electronic control and monitoring service through a remote diagnostics centre, it is claimed that these devices will maximise comfort and efficiency for boiler owners.

There is no doubt that the early identification of impending boiler problems will provide an extra level of confidence for households, particularly during the winter months. Nobody welcomes an unexpected boiler breakdown in the middle of winter.

There are other benefits too. Most boiler owners are familiar with the situation where an engineer has been called out to investigate the cause of a malfunctioning boiler. The diagnosis usually requires a considerable amount of time fiddling with the boiler’s internal components and a certain amount of head scratching. Inevitably, the engineer comes to a conclusion which usually centres on the recommendation of the fitting a new part. Fitting the part is a straightforward procedure. Ordering and getting the part is another matter.

With RADS, a remote diagnosis should ensure that the engineer arrives pre-supplied with the necessary components.

Through a RADS system, the boiler will be in what is referred to as ‘real-time’ contact with the remote monitoring centre. Real-time is one of those phrases that sound high-tech, but simply means connected to and maintaining a regular contact with the centre. This ensures that the boiler’s operational performance can be monitored for unusual working behaviour patterns. This monitoring will eventually produce a boiler behaviour history, which, when combined with information from maintenance and repair history, will provide valuable information for analytics and engineers.

When an actual or potential malfunction is detected by the provider’s monitoring centre, the centre alerts an engineer. Remotely, the provider’s engineer can use diagnostics software and analysis to determine the possible cause of the problem. In doing so, he can pre-source and obtain any necessary parts from the energy provider’s stores.

Meanwhile, the energy provider’s monitoring centre contacts the boiler owner to arrange a convenient time for the engineer to call. This means that the provider’s engineer can attend to the boiler at a pre-determined time, carry out a few checks to confirm the fault, and immediately install any necessary parts. This, of course, can save considerable cost and inconvenience for the householder and also improve the efficiency of the provider’s engineering department.

Many boiler manufacturers are now building boilers with this technology pre-installed in anticipation of an eventual general consumer uptake of the system. Other companies are investing in developments to provide the necessary components to allow existing boilers to be modified to function with RADS.

Along with remotely controlled and monitored smart meters, boiler-monitoring looks likely to become a normal part of an energy supplier’s service.

How far these developments will provide other additional benefits to consumers remains to be seen.

Having remote boiler diagnostics may remove the potential for intervention by the homeowner. The service provided by the energy provider will ensure that the provider’s engineers facilitate repairs and maintenance to their customer’s boilers. This will allow them to monopolise the boiler repair and maintenance trade, with the potential to affect the businesses of many small, independent boiler heating and plumbing specialists.

Along with smart meters, it could also provide a disincentive to energy customers to source competitively priced alternative energy sources and to easily switch between suppliers.

Perhaps the greatest and growing concern for homeowners is the increasing monitoring of their activity by monolithic companies who have become obsessed with collecting and analysing data connected with consumers and their behaviours. This information is often used to influence and change behaviour patterns in a manner that is beneficial to the companies who collect it, or to those who sell it on to other interested parties.

New energy heating and control technology undoubtedly brings many benefits to homeowners and their families, but when the control of that technology is removed from the homeowner, a certain amount of discomfort about the issues surrounding remotely controlled systems will have to be overcome before they are totally accepted without suspicion

The Causes of Low Water Pressure

For some people low water pressure or a loss of the mains water completely, can be nothing more than a temporary inconvenience, particularly if it results from a water service provider’s routine maintenance on the mains supply network.

If this is the case, then the householder may have been fortunate enough to receive the courtesy of advanced notification from the provider. On the other hand, a sudden interruption to supply might be the result of a burst water pipe or other unpredictable system failure, hopefully before leaving the mains and the responsibility of the water provider.

Low water pressure issues that cannot be attributed to the fault of the provider can be caused by numerous problems.

Low pressure can sometimes be an issue where neighbours share a supply pipe from the mains. In these cases, pressure may seem to fluctuate particularly at regular times throughout the day. Increased demand on the water supply will reduce available pressure and this can often be observed in summer when other residents reduce pressure in the supply pipe by watering their gardens.

When a water provider has determined that the pressure at the mains boundary is sufficient, the capacity or internal diameter of the supply pipe may be a problem.

Where a pressure or a flow and capacity issue arises on a shared supply pipe, the owners of the properties that the pipe supplies are jointly responsible for the pipe’s maintenance.

When investigating water pressure issues within the home, a first consideration should be the extent or limitation of the problem. The problem may be restricted to an individual appliance or to an entire system’s function.

A water filter on the inlet valve of a boiler may be blocked and could need cleaning and likewise, a slow running tap may have the same problem on the outlet filter, if one is installed.

Shower-heads can become blocked with lime-scale, seriously impeding flow or preventing operation altogether. These may simply require cleaning or replacement.

Where there appears to be a drop in water pressure throughout the entire domestic water supply of a property, a leak in the pipe-work may be the cause of the problem. Apart from the obvious visual evidence of leaking pipes inside the home, leaks can occur both internally and externally that might not be quite so conspicuous.

If you are fortunate to have a water meter installed it can be worth turning off all the water utilising appliances and taps and taking a reading from the meter. If, after a few hours with no domestic water consumption, a further reading of the meter shows an increased unit usage, then a leak in the domestic system could be the problem. Externally, a leak in the pipe-work below ground will usually show up as a wet patch, particularly on a dry day.

Sometimes a leak in a pipe will be heard and identified by the hissing sound of escaping water under pressure.

Over time, pipe-work supplying the water from the mains can become restricted or completely blocked by accumulated deposits. This is a particular problem with old galvanised pipe-work. Replacing this pipe-work with copper is the best solution.

In some old properties, lead pipe-work may still be installed. This can be identified by gently scratching the exposed pipe. The resulting scratch mark will be silver in colour. Lead pipe-work is quite soft and susceptible to accidental crushing and bending which can restrict the flow rate and pressure within the damaged pipe.

At the point where a water meter is installed, or where the water supply enters the property it usual to find a stop valve. Sometimes, particularly after plumbing has occurred within the property, this valve is turned off and then on completion of the work, is not turned back on fully.

Occasionally, and particularly following provider maintenance work, air and debris can accumulate behind this valve and restrict or prevent flow. Turning on a tap within the property and then turning the stop valve on and off a few times should resolve the problem. If an airlock has been a problem, the water will splutter out of the tap and then normal water pressure should be restored.

In some cases, and particularly where a new occupant has moved into a property, those occupants may be aware of a water pressure difference between their old and the new property. A reduction in water pressure is likely to be noticed where the new property is on a hill or where a supply pipe facilitates the water requirements of numerous homes.

Many new appliances require a minimum operational water pressures and a householder is well advised to ensure that the water supply to the property is capable of meeting the appliance’s requirements. Some appliances will fail to operate without a minimum pressure for safety reasons, for example shower units and boilers.

Water service providers aim to supply a water pressure of 1 bar at the mains boundary. If for some reason the home-owner is unable to meet the minimum pressure required by appliances, the installation of an accumulator water tank may provide a solution. These cylinders store a supply of water imparting and maintaining a suitable pressure which can supply appliances where low-pressure issues would otherwise prevent operation.

It is worth noting that where regular intermittent low-pressure issues occur which are caused by a water provider’s inability to maintain a regular minimum water pressure above 0.7 bar, the home-owner may be entitled to compensation.

Where a provider affects a householder’s mains supply by delivering a low water pressure below 0.7 bar, and lasting for over one hour on two or more occasions within 28 days of each other, the householder may be able to claim compensation from their provider. However, planned maintenance and emergency work on the mains network are excluded from this provision.