DIY Plumbing and Pollution

One of the greatest eureka moments in human history was the discovery that many diseases were contracted by people drinking contaminated water supplies.

These horrible diseases plagued our early towns and cities and were compounded by the lack of sanitation and the fact that human activity created waste compounds that were not being correctly disposed of. Blood and waste products from animal slaughter, toxins and heavy metals produced by manufacturing processes and the faecal and food waste products from human habitation trickled through open street troughs and into the nearest river or watercourse. These same watercourses provided much of the drinking water the inhabitants who could not afford cheap ale were forced to drink.

Life expectancy was short and early childhood mortality was the norm.

Today, things are much different. Sewage and other foul water wastes are carefully directed along dedicated pipe networks to vast treatment plants. Here they are carefully treated to clean out most of the harmful components before they are allowed to enter streams, rivers and oceans.

Surface water from roofs and other surfaces are kept separate and, because of their relative cleanliness, directed straight into streams and other watercourses where they become diluted and rendered harmless.

All very notable and efficient. Or is it?

Unfortunately, too much material that should be sent into the sewage system for treatment is currently being wrongly directed into the surface water system. Although not entirely the cause of the problem, much of the blame is being placed at the door of over enthusiastic DIY operatives who incompetently plumb appliance’s wastewater discharge pipes into the wrong drain. Dishwashers, washing machines, baths and sinks, even toilets can inadvertently have their waste flushed into the wrong pipe.

This rise in DIY activity is believed to be one of the contributing factors. The proliferation of daytime TV DIY and house renovation programmes seems to have spurred an increase in inexperienced householders keen to save money by carrying out their own installations and home improvement work. This, coupled with the recession, which has deterred people from moving house and motivated them to alternatively embark on home improvement projects instead, has compounded the problem.

Today, the ease at which DIY appliances, fittings and other components and tools can be sourced, and the relatively cheap price of these items, has made DIY a leisure activity for many.

The recession has also meant that affording the services of qualified trades people has become increasingly beyond the financial means of many householders.

As a result, more and more effluent and other toxic substances are finding their way into the wrong drains and subsequently directly into the natural water systems.

DEFRA predicts that by 2017, over half a million properties in the UK will have misconnected and technically illegal drainage connections installed. Currently, in some areas, one in five households is known to have incorrectly plumbed drainage systems.

The damage caused to the environment is substantial. The decomposing material in rivers and seas removes oxygen from the water. This suffocates fish and encourages eutrophication, or the proliferation of algae, which forms dense blankets on water surfaces cutting out sunlight. Salmon, perch, pike and trout all succumb to this unnatural imbalance created by the disruption of normal environmental processes.

Toxic chemicals can cause undesirable mutations in wildlife. The endocrine disrupters released from contraceptive pills and flushed directly into clean watercourses can cause gender alterations in fish and other aquatic life.

However, not all problems are caused by hapless DIY operatives.

Too often toxic materials are deliberately discarded into drains, particularly street drains. Oil, antifreeze, and other motoring products are often flushed directly into them by inconsiderate vehicle owners.

The increase in the construction of external hardcover surfaces prevents natural drainage and following a rain downpour, water, and the debris collected on these surface gushes into storm drains, causing considerable pollution.

Not only is a polluted water course unattractive, the smell of decomposing organic material coupled with the myriad of unexpected chemical reactions that may occur can be quite unpleasant for neighbouring households.

So concerned are various environmental groups about this growing problem, that many are now monitoring watercourses to detect sewage contamination. Dyes can be added to pipe networks to discover the origins of contamination points.

Fly populations that inhabit waterside environments are being monitored to detect alterations in normal populations caused by trace contaminants. When detected, the Environment Agency is informed. The Agency is then obliged to carry out further investigations to try to determine the source of the problem before it becomes a serious issue.

The government has also set up the Connect Right campaign. This body provides information and advice to homeowners and developers about connecting appliances to the correct drainage system. It also provides links to accredited Water Safe plumbing engineers. These plumbers and fitters have the relevant experience and the technical understanding of environmental issues to ensure that any work is correctly undertaken.

Homeowners with older properties are also recommended to have their drainage systems regularly checked to ensure correct operation. Deterioration of older pipe-work can cause seepage of contaminants into the wider environment causing harm to wildlife and human populations alike.

For homeowners and DIY enthusiasts, taking care to ensure that drainage systems are correctly identified prior to embarking on installations will help to reduce the problems associated with incorrect connection issues.

Where any plumbing work lies beyond the scope or experience of the householder, employing a professional and competent plumber will ensure that our natural habitats remain as unaffected by human activity as is possible.

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.

 

 

 

Plumbing-In a Washing Machine or Dishwasher

With today’s easily obtainable plumbing supplies and fittings, plumbing a new washing machine or dishwasher is a relatively straightforward operation. Simple installations are well within the capabilities of any competent DIY enthusiast. Installations that are more complex may need the assistance of a general handyman or plumber to ensure that pipe fittings are correctly incorporated to allow the appliance to function reliably.

Perhaps the simplest installation is the replacement of an existing appliance with a new one. So long as the electricity plug has been removed from its socket, the water in-line supply valve turned off, the hose(s) unscrewed and the waste pipe disconnected; the old appliance can be eased from its existing position and disposed of.

In the case of a new washing machine, first, remove all packaging and either keep it in case it may be required again, or dispose of it. The main thing is to get it out of the way. Then, and with reference to the manufacturer’s installation instructions, the drum transit restraining bolts must be removed completely from the machine. These bolts prevent the drum from moving on its axle during transport. Failure to remove the bolts before operating the machine will seriously damage it. Keep these bolts safe in case it becomes necessary to transport the machine in the future.

To prevent unbalanced drum operation, the machine must be level. This can be achieved using a spirit level whilst adjusting the machine feet. The machine must also be stable and not able to rock when operating. The feet should also be adjusted to ensure that the machine will fit comfortably below any work surfaces.

Modern washing machines now have a single water connection hose. This has a fitting coloured blue and should be screwed onto the cold water supply fitting. This fitting should only be tightened by hand. The drainage and electrical fittings should all fit into the old connections with no need for modification. The new washing machine can then be slid into the existing space, taking care not to kink any of the pipes whilst doing so. The water supply can then be turned back on at the inline valve. Prior to switching on the electrical supply, it is a good idea to ensure that the operating switch on the machine is turned off otherwise the machine door will automatically lock when the power is supplied.

The manufacturer’s instructions will probably recommend running the machine empty on a hot wash prior to attempting to wash any fabrics. During the first operation, it is a wise precaution to monitor the machine and connections for any problems that might arise.

Installing a replacement dishwasher follows the same procedure; however, there are no transit bolts to remove. The machine must be level to ensure effective dish washing operation. Fittings are generally identical the previous installation.

To provide installation points for a new washing machine or dishwasher, slightly more complex plumbing procedures are required; however, it is possible to obtain all the necessary parts in a kit from major DIY outlets.

The first thing to consider is where to position the appliance. Not all appliances have to be located in the kitchen. Some homeowners prefer to locate appliances, particularly washing machines, in garages or conservatories. However, consideration must be given to frost protection.

Dishwashers tend to be located in the kitchen due to the frequency of operation and for convenience.

What both appliances require are a power source and water and waste connections. For that reason, both appliances tend to be located in the kitchen close to the sink where access to a cold water supply and drainage is readily available. In all probability, an electric socket will also be on hand to plug the appliance into.

To make a water connection to a cold pipe, first, isolate the pipe area or turn off the rising main. Drain the system as much as possible and then cut out a section of the supply pipe to accommodate a T fitting. All fittings should be either soldered or compression joints, depending on preference. An adequate length of pipe should be fitted into the T with an isolation valve to cut off the water supply in the event of a hose failure. A suitable connector should then be fixed to the end of the pipe to accommodate the machine hose. Incorporating a check valve should also be considered.

It is possible to obtain self-boring fittings that simply screw into existing pipework. These should be securely attached to a wall and in the off position prior to operating the self-tapping valve. It is also advisable to check with the water supplier that these fittings are permitted.

To fit a waste drainage connection firstly check the appliance manufacturer’s recommendations to ensure that a suitable outlet will be provided. The most common outlet consists of a vertical pipe with a minimum 40 mm diameter. This vertical pipe must have its top opening high enough to prevent any back-flow of water into the machine. This can be plumbed into the sink waste pipe with a suitable connection. The top of the pipe accommodates the machine waste pipe that simply hooks onto it. It is possible for two machine drainage pipes to be hooked onto this down pipe but it might not be advisable to have both machines draining at the same time.

Alternatively, a dedicated drainage fitting can be installed directly into the sink drainage system just above the trap. This fitting usually has two branches to accommodate two appliance drain hoses. Prior to fitting the drain hoses, blocking caps, either fitted internally or externally on each branch must be removed. In some instances, they may need to be sawn off.

To fit either appliance in a garage or alternative position, it will be necessary to provide independent water and drainage supply pipes. Although this can be straightforward if services are within easy access, providing these points may require professional intervention, particularly where new electrical installations will be required.

In general, installing a washing machine or dishwasher can be carried out without the need to employ a professional plumbing engineer.

Water Damage Due to Plumbing Issues

Water damage as a result of freak weather conditions can be very difficult to predict and prevent. Heavy rain and the resulting flooding can catch out even the best prepared, causing considerable damage and disruption to homes and businesses alike. The resources required to prevent flooding caused by natural events are mostly beyond the reach of individual homeowners and businesses.

Domestic plumbing failures can be equally catastrophic, causing misery and financial problems for the households in which they occur. Water can be particularly destructive. Water damaged goods and appliances can rarely be saved and must be discarded and replaced. Personal belongings with sentimental and irreplaceable significance can be lost forever.

One of the biggest hurdles to overcome after severe water damage is trying to dry out the water soaked building fabric. Air is essential in the drying out process. Where the air is absent or drying takes too long, microbial action produces unpleasant odours, which are very difficult to get rid of. Waterlogged carpets and water seepage under lino or wood laminate floorings make them particularly susceptible to such deterioration. Walls and plaster will also crumble and boarding will warp and distort. Severe water damage requires professional attention.

Apart from natural causes, water damage can be caused by burst pipes and leaks from appliances. These leaks usually occur as a result of poor workmanship, accidental damage or just normal, but un-noticed, wear and tear.

When a leak occurs, the severity of the damage is often compounded by a lack of awareness by householders of the location of the mains stopcock and how to use it. Around fifteen litres of water per minute will gush from a severed mains pipe. Any delay in closing off the water supply can be disastrous.

Washing machine hoses are high on the list of failures resulting in insurance claims for water damage. Although the hoses are designed to last around ten years, they should be frequently inspected for signs of deterioration. Any visible cracks or hardening of the rubber should cause concern and the hoses should be replaced. Some washing machine manufacturers advise replacing hoses every two years. Many homeowners turn off the isolation valves supplying water to the hose connections between each use of the washing machine as an added precaution. However, this may not always be practical and is dependent on ease of access.

Dishwasher hoses and draining pipes require similar inspection, as do the door seals around both appliances.

Old pipes, particularly galvanised ones, corrode over time. Galvanised pipes were used widely up until the 1970′s but are rarely used in domestic property now. They have an expected working lifespan of about thirty years, so if your property still has them it might be a good idea to replace them before problems occur.

Accidental damage frequently happens to pipe work, particularly when it is concealed within walls and beneath floorboards. It is very easy to inadvertently puncture a pipe when hammering a nail into a wall or wooden floor. Occasionally the punctured pipe can go unnoticed for some time, slowly leaking water into its surroundings and causing considerable unseen damage.

Water damage caused by poor plumbing practices and incompetent workmanship is often associated with DIY enthusiasts and their over ambitious projects. When attempting any plumbing work it is essential to familiarise yourself with the procedures and to ensure that all the necessary parts and tools are available. Failure to shut off the water supply prior to starting work is a big cause of water damage. Never cut corners or attempt to modify pipes and fittings beyond their original purpose. If in doubt, get a professional plumber in to do the work.

However, what might appear to be a professional plumber may not turn out to be one. Although it is a good idea to consider a plumber recommended by relatives and friends through word of mouth, never take on a plumbing engineer at face value. Always thoroughly check the credentials of a plumber. Ideally, they should belong to a recognised trade body, such as The Association of Plumbers and Heating Contractors. Being a member of such a body can give added protection should the plumber’s work be called into question. Do background checks on the plumber to establish the authenticity of the business and the length of time the business has been trading.

Remember to ensure that the plumber has adequate Public Liability Insurance. Insist on seeing proof of it prior to engaging their services. Remember that in the absence of suitable insurance, you are vicariously liable for third party damage if things go wrong. Having to claim for damage on your own contents insurance can cause future premiums to rise considerably.

Getting a written contract reflecting the work requirements and timescale for completion is essential. The contract should also clearly state all terms and conditions. Do ensure that the terms and conditions do not contain any unfavourable clauses. It may seem a little over precautionary, but if things do go wrong and subsequent water damage occurs to your property, a written contract will be more secure than a verbal one when seeking compensation. In dealing with a plumber, or any tradesperson, what might have been said cannot be verified. When it is written in black and white and signed by both parties, unless the wording is ambiguous, the contract is binding.

A good plumber will always produce workmanship to the satisfaction of a client. If things go wrong, first take the matter up with the plumbing engineers and give them a chance to rectify the situation. Where damage has occurred, their insurance will cover the cost of putting right the damage.

Always take photographs or videos of work in progress, damage or any evident faulty or questionable plumbing practices. These will be of great importance should you ever need to pursue a rogue tradesman through the small claims court.

Remember that if a plumbing and heating contractor is engaged to carry out gas work on a gas appliance, they must be registered with Gas Safe and competent to undertake the particular work. Always check that the ID card and photo match the engineer.

Water damage caused by plumbing issues may not be entirely preventable, but can be minimised by taking adequate precautions. There are devices that will produce an audible alarm if leaking water is detected. Some of these are simply strips of water sensitive electronics, which are often self-contained and simple to install. Other more sophisticated devices can be installed inline on the water pipe and will detect abnormal or extended water flow patterns. They then activate to turn off the water, limiting damage.

No householder likes to have to deal with water damage caused by plumbing issues. With a little forethought, the chances of such issues occurring are substantially reduced. Knowing how to deal with them if they should occur will help to make the procedure a little less disheartening.

 

Backflow in Plumbing

Clean, wholesome drinking water. We can take it for granted. Turn on the cold-water tap and it is there.

Wastewater. The grey soup from washing machines, washbasins, baths, and showers. It disappears down sinks and drains never to be seen again.

It would seem quite important that the two should never be allowed to mix and be inadvertently consumed by members of the household, or indeed other unsuspecting households connected to the supply.

Yet without precautions, clean water can become contaminated with materials that can have serious implications for human health. Toxic chemicals and dangerous micro-organisms can infiltrate domestic water supplies if suitable barriers are not in place to prevent them doing so.

The importance of maintaining an effective barrier between clean (potable) drinking water and the water using devices and appliances connected to the mains supply within the home should not be under-estimated. There are thousands of domestic water contamination incidents recorded each year, with some resulting in fatalities.

The biggest cause of problems involving domestic potable water contamination results from cross-connection issues. A contaminated source of water has the potential to be drawn into the clean water supply when it is connected to it. For example, a garden hose connected to the water supply could create a cross connection. If the flow of water through the connected hose is induced in the opposite direction this is referred to as backflow.

There are numerous cross connection unions in the typical home, from dishwashers and washing machines to combi boilers and mixer taps.

Backflow can be initiated by a number of adverse conditions such as a burst water main causing a sudden drop in pressure, a high demand for water on a supply line or frozen pipes interfering with the flow.

There are two main types of backflow. Siphonage and backpressure.

Siphonage may occur when the pressure of the mains water is not great enough to overcome the tendency for water to flow to its lowest level. For example, when siphoning a liquid from one container to another, a vacuum is created within the siphon tube by removing the air. So long as the siphon tube exit is positioned at a lower level than the level of the siphon tube entrance, the liquid will flow to its lowest level. This facilitates the flow of the liquid from one container to another.

Likewise, a garden hose with one end attached to the mains water supply and the other left submerged in a garden pond has the potential to contaminate the mains supply by the process of siphonage.

Backpressure is caused where the pressure in a system connected to the mains supply is able to overcome the mains pressure supplying it. For example, when water is heated by a combi boiler the water expands. As a result, the increased pressure has the potential to overcome the mains water pressure and cause a reversal of flow back into the mains water system. The same thing has the potential to occur with central heating fluids if the filling loop is left in place in the absence of a backflow prevention device.

The Water Supply (Water Fittings) Regulations 1999 makes the fitting of backflow prevention devices and techniques mandatory. The regulations also make it incumbent on the homeowner or a competent engineer, to install and maintain systems to comply with the regulations. They must prevent contamination and also give notice to the local council of any installation work that falls under The Buildings Regulations notification requirements.

The type of prevention device or method that must be employed can be established by referring to the list of water categories set out in the regulations. This list categorises the seriousness of contamination fluid risk on a score of one to five, with five being the most serious.

The simplest method of backflow prevention is to create an air gap. This is very effective and can be seen in operation with kitchen taps, sink taps, and toilet cisterns. The distance provided by the air gap is determined by the risk as set out in the regulations.

A tundish can also act as a backflow prevention device by virtue of the air gap it produces.

For direct connection, and in compliance with the necessary precautions determined by the Act, check valves, either single or double provide an effective barrier against potential contamination risks. These are easily fitted into the pipe-work where connections are made. A garden tap is required to be fitted with a check valve between a hose connection point and the tap bib.

Other forms of backflow prevention include ball valves in water storage tanks, where the water outlet must be above any overflow outlet, and integral protectors, such as are often found in mixer taps and non-return valves.

Reduced pressure zone valves (RPZ) may also be installed where required, but must be installed by a competent person.

Although it is not always necessary to fit check valves on mixer taps that do not have integral protectors, it is advisable.

It is also important to remember that tap outlets are a prime source of contamination and should be regularly cleaned. It is not uncommon to see contaminated material being placed in contact with the outlet or splashing back into it. Microbiological contaminants can thrive on tap outlets and contaminate further supplies.

When purchasing fittings it is important to ensure that they comply with the Water Regulations. It is not illegal to sell fittings that do not comply, but it is illegal to fit them.

The Act also stipulates that any fittings are installed in such a manner that they are easily accessible for maintenance and are adequately protected against frost.

The Water Regulations Advisory Scheme (WRAS) can provide copies of the Water Regulations (Water Fittings) Act 1999 and provide advice regarding compliance and the suitability of fittings.

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.

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.

 

 

 

Identifying and Fixing a Damaged Heating Pipe

There is no doubt about. You have a boiler losing pressure and you have no idea why. You’ve checked the central heating radiators and pipes for any visual signs of leaks and found nothing.

You’ve also called out the boiler engineers and they have checked the boiler over for faults and replaced a suspect part. The expansion vessel is working normally and there is no overflow from the pressure release valve.

Yet still, over a period of a few days the boiler operating pressure starts falling and you have to keep topping the system up.

The real worry is that there is a leaking pipe under the floorboards, or worse still, buried within the new hydronic under-floor heating system you’ve just had installed under the ground floor.

This is going to take a little bit of detective work to find just where that leak is hiding.

That is of course if it is a leak.

Just because boiler engineers are Gas Safe registered it does not mean they are all seasoned and highly experienced. Unfortunately, there is a minority who are inclined to diagnose the most likely fault, replace a part and hope for the best. When they are called back, they simply move on to the next likely fault and eventually fix the boiler by the expensive process of gradual elimination.

So, back to our devil of a problem. To see whether the boiler is at fault, the following technique may help.

The boiler should be isolated from the system by turning off the flow and return valves to heating networks and the mains inlet source. The boiler must have at least one bar of internal pressure registering on the pressure gauge.

The boiler should be left unused for at least 12 hours. If the pressure drops within that time, then the fault very likely lies with the boiler. If the pressure is maintained, the fault probably lies somewhere within the heating circulatory system.

Of course, whilst the test is in operation there will be no domestic hot water available, particularly if you have a combi type boiler. If you are fortunate to have a hot water storage cylinder with an alternative electrical element heating source, you will not be affected by this temporary domestic hot water problem.

If the boiler appears to be at fault, get the boiler engineers back and insist that they rectify the fault.

If the heating circulatory system appears to be the problem, you should have a dedicated heating network that feeds the under-floor heating system separately from the radiator network. The manifold which connects the hot water to the under-floor heating pipes should have isolation valves fitted. On this manifold, it is often usually possible to turn off the under-floor heating or the radiator network separately so that each can run either together or independently depending on the household requirements.

With the boiler operating at normal pressure, isolate each network flow and return valves independently for at least 12 hours and monitor the boiler pressure. A drop in pressure on either network will indicate which has the leak. A drop in pressure on both networks means that you either have leaks in both networks or that there is a leak in the pipework from the boiler to the manifold. To identify whether the latter is the case, turn off all heating network flow and return valves with the boiler operating at normal pressure for 12 hours. If the pressure drops then the leak lies on that circuit.

If there are no pressure drops within the circulatory system, call the boiler engineers back, again.

When diagnostics suggest that the under-floor heating network has a leak, depending on the warranty you have, contact the installers. If you installed it yourself or it is out of warranty, check your household insurance for cover.

It is possible to get a general idea of where the under-floor heating leak is located by using thermal imaging equipment. If it can be located, the area can be dug up and the leak found and repaired or bypassed with a new loop of pipe.

Dealing with leaks in under-floor heating can be expensive to address. The wrong diagnosis can lead to the entire floor being dug up and no leak being found. When initially laying under-floor heating it is wise to protect any pipes from the corrosive action of concrete.

If all indications lead you to suspect that the leak lies somewhere within the central heating network, it is important to thoroughly inspect all accessible parts of the pipe-work and attached appliances for any visual signs of leakage. On hot pipes, water from minor leaks will very quickly evaporate.

Where forethought has provided isolation valves at important junctions, these can be used to isolate sections in the elimination process previously described.

Narrowing down the area of the leak will allow for close scrutiny of a small section of visible pipes and fittings. Occasionally the most unlikely source of a leak may be the culprit, such as a loose compression fitting or a faulty radiator check valve. Appliance fittings such as those attaching pumps and motorised valves must also be checked.

Once narrowed down and without any visual signs of a leak, attention must be drawn to pipe-work hidden below floorboards etc.

Lifting floorboards in a limited area may give an instant visual indication of a leaking pipe. Possible compression fitting failings or badly soldered joints will show up as a damp patch on the surface beneath the fittings. Sometimes a nail hammered into floorboards and puncturing a pipe is the culprit.

Before attempting to repair a leaking pipe, always turn off the boiler and mains water. If the heating flow section cannot be isolated, the system will have to be drained.

Repair is usually straightforward and limited to either re-tightening or replacing compression joints, or removing the affected section of copper or plastic pipework. A new piece of pipe is then inserted and secured with appropriate fittings. The use of in-system circulating leak repair fluids is not recommended. They can cause other damage to the system and often invalidate warranties.

Once the pipe-work is repaired, the system can be re-filled. Do not forget to include inhibitor. Radiators may need bleeding.

Hopefully, the problem will be solved. However in some rare cases, leaks are never found, or one is discovered and fixed, only for more to appear. The householder continues to suffer from system pressure issues that indicate leaking pipes and has to continue the unresolved chore of frequently topping up the system. In cases like these, it is likely that there are numerous minor failings, particularly in old systems. In these situations, a complete central heating replacement is probably long overdue.

 

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.

 

 

 

 

Unvented Hot Water Cylinders – The Future?

An unvented hot water cylinder can be the answer to a loft converter’s prayer. Especially when available space and the shortage of it is a major consideration that most homeowners are faced with when considering improvements to hot water installations.

The biggest drawback with vented hot water cylinders is the need for a water storage header feed tank, usually situated in the loft. There the water sits, waiting to be heated and often exposed to airborne contaminants. In addition, when the time comes for it to work its way into the cylinder for heating and then on its journey to a hot water outlet, it must do so usually under the gentle force of gravity and with a little assistance from atmospheric pressure. The unbalanced pressure between mains cold water and gravity fed hot water can lead to irritating problems. A good head of pressure may be achievable from a header tank in the loft of a three-story building, but flats and single story dwellings will need to install pumps to maintain an acceptable flow rate of hot water.

Added to that, and probably an overlooked factor is the low level of copper contamination leached from the copper cylinder into the heated water. It is probably wise to avoid swallowing it and adding to the other environmental copper sources slowly accumulating within our bodies.

Perhaps, in the days before central heating and cylinder jackets, there was something comforting about that great copper vessel hidden away in the airing cupboard alongside a couple of bubbling demijohns, mushroom spawn and germinating cucumber plants. However, time moves on and brings with it progress and advantages that can revolutionise our way of life.

Unvented hot water cylinders have been around for some time, particularly on the continent. Consequently, they are well tried and tested and for a variety of reasons, very efficient.

There are two types. Direct and Indirect. The direct system is heated solely by two internal electric elements.

The indirect system is heated by an external boiler, although a backup single internal electric element is usually incorporated. The external boiler heats water, which then passes through a copper coil in the cylinder. The heat is exchanged to the water in the cylinder and returns back to the boiler for re-heating. The requirement for heating is governed by a thermostat attached to the cylinder.

An unvented system is connected directly to the mains supply eliminating any need for a header feed tank. This mains supply provides the great advantage of increased water pressure compared to that of a vented system. It also eliminates any need for complimentary pumps to increase hot water pressure.

This extra pressure on the hot water system allows for greater flexibility in the choice of mixer taps and the benefits of being able to install power showers.

On a suitable and well-installed system, very little drop in water pressure is noticed when multiple hot water outlets are operated at the same time.

Because this system operates at a greater pressure than a vented installation, certain modifications are incorporated in the design to accommodate the differences and eliminate potential problems. A device called a balancer is usually installed on the mains inlet to ensure that equal pressure is present on both the hot and cold outlets.

The cylinder itself is generally made of stainless steel and constructed to withstand the extra pressure it is subjected to. The cylinder is also insulated with materials that represent the cutting edge of energy conservation, and as such dramatically reduce the loss of heat into the atmosphere and consequently increase the efficiency of the system.

Hot water expands and in the absence of the expansion route provided by a vented system, the unvented cylinder incorporates either a small external diaphragm water and air operated expansion vessel, or an internal air bubble type expansion facility. One or more tundish safety components are added for extra safety and they also give a visual indication if a heating problem occurs.

Where unvented systems have been installed without proper consideration, the most common problem for homeowners has been that the system does not perform within expected tolerances. An unvented system, operating on mains pressure requires a minimum mains pressure and minimum mains flow rate to operate correctly. This is often not checked prior to installation. An unvented system requires a minimum mains pressure of 1.5 bar and a minimum flow rate of 20 litres/minute.

Where insufficient mains water pressure and flow rates are identified it is possible to acquire an additional accumulator cylinder. This device intercepts the mains supply prior to it entering the hot water cylinder and stores the extra water, conveying additional pressure directly to it so that when water is drawn through the unvented cylinder it is replaced by cold water from the accumulator at an adequate pressure.

The compact and uncomplicated nature of unvented hot water cylinders is also enhanced by a reduced maintenance requirement and a considerable warranty period on the cylinder.

Where space is at a premium they are ideally suited, and compared to the output limitations of room sealed combination boilers, they are likely to be the system of choice. The potential for modification to enable contribution from other external heat sources i.e. solar power is possible.

Unvented Hot Water Cylinders – The Future?

An unvented hot water cylinder is much, much more than the answer to a loft converter’s prayer. However, space and the shortage of it certainly seems to be a major consideration most homeowners are confronted with when considering improvements to hot water installations.

The biggest drawback of course with vented hot water cylinders is the need for a water storage header feed tank, usually situated in the loft. There the water sits, waiting to be heated and often exposed to airborne contaminants. In addition, when the time comes for it to work its way into the cylinder for heating and then on its journey to a hot water outlet, it must do so usually under the gentle force of gravity and with a little assistance from atmospheric pressure. The unbalanced pressure between mains cold water and gravity fed hot water can lead to irritating problems. A good head of pressure may be achievable from a header tank in the loft of a three-story building, but flats and single story dwellings will need to install pumps to maintain an acceptable flow rate of hot water.

Added to that, and probably an overlooked factor is the low level of copper contamination leached from the copper cylinder into the heated water. It is probably wise to avoid swallowing it and adding to the other environmental copper sources slowly accumulating within our bodies.

Perhaps, in the days before central heating and cylinder jackets, there was something comforting about that great copper vessel hidden away in the airing cupboard alongside a couple of bubbling demijohns, mushroom spawn and germinating cucumber plants. However, time moves on and brings with it progress and advantages that can revolutionise our way of life.

Unvented hot water cylinders have been around for some time, particularly on the continent. Consequently, they are well tried and tested and for a variety of reasons, very efficient.

There are two types. Direct and Indirect. The direct system is heated solely by two internal electric elements.

The indirect system is heated by an external boiler, although a backup single internal electric element is usually incorporated. The external boiler heats water, which then passes through a copper coil in the cylinder. The heat is exchanged to the water in the cylinder and returns back to the boiler for re-heating. The requirement for heating is governed by a thermostat attached to the cylinder.

An unvented system is connected directly to the mains supply eliminating any need for a header feed tank. This mains supply provides the great advantage of increased water pressure compared to that of a vented system. It also eliminates any need for complimentary pumps to increase hot water pressure.

This extra pressure on the hot water system allows for greater flexibility in the choice of mixer taps and the benefits of being able to install power showers.

On a suitable and well-installed system, very little drop in water pressure is noticed when multiple hot water outlets are operated at the same time.

Because this system operates at a greater pressure than a vented installation, certain modifications are incorporated in the design to accommodate the differences and eliminate potential problems. A device called a balancer is usually installed on the mains inlet to ensure that equal pressure is present on both the hot and cold outlets.

The cylinder itself is generally made of stainless steel and constructed to withstand the extra pressure it is subjected to. The cylinder is also insulated with materials that represent the cutting edge of energy conservation, and as such dramatically reduce the loss of heat into the atmosphere and consequently increase the efficiency of the system.

Hot water expands and in the absence of the expansion route provided by a vented system, the unvented cylinder incorporates either a small external diaphragm water and air operated expansion vessel, or an internal air bubble type expansion facility. One or more tundish safety components are added for extra safety and they also give a visual indication if a heating problem occurs.

Where unvented systems have been installed without proper consideration, the most common problem for homeowners has been that the system does not perform within expected tolerances. An unvented system, operating on mains pressure requires a minimum mains pressure and minimum mains flow rate to operate correctly. This is often not checked prior to installation. An unvented system requires a minimum mains pressure of 1.5 bar and a minimum flow rate of 20 litres/minute.

Where insufficient mains water pressure and flow rates are identified it is possible to acquire an additional accumulator cylinder. This device intercepts the mains supply prior to it entering the hot water cylinder and stores the extra water, conveying additional pressure directly to it so that when water is drawn through the unvented cylinder it is replaced by cold water from the accumulator at an adequate pressure.

The compact and uncomplicated nature of unvented hot water cylinders is also enhanced by a reduced maintenance requirement and a considerable warranty period on the cylinder.

Where space is at a premium they are ideally suited, and compared to the output limitations of room sealed combination boilers, they are likely to be the system of choice. The potential for modification to enable contribution from other external heat sources i.e. solar power is possible.

The Building Regulations Approved Document G (section G3) regulations require that a hot water storage vessel with a capacity of more than 15 litres, which does not incorporate a vent pipe to the atmosphere, should be installed, commissioned, inspected and serviced by a competent person.