Green Deal

Introduced in 2013, it was heralded as the biggest programme of housing improvement since the second world war.

As a government-backed scheme, it was set up to provide loans to households to facilitate energy efficiency improvements.

The Green Deal loans gave a source of finance that differed significantly from bank loans or other forms of credit. Rather than the outstanding loan debt being placed on the homeowner or householder, it was placed upon the property and designed to be recouped through future energy bills.

An energy assessment to clarify what energy saving measures were appropriate for the property was required in order to access the funding.

As a safeguard against high energy bills, it was implemented in a way that the loan repayments should never exceed the savings in energy provided by the improvements.

These improvements included such items as new boilers, double glazing, solid wall insulation and solar panels.

The Green Deal loans carried with them interest rates ranging from 7.9% to 10.3% and the loans were intended to spread repayment over 10 to 25 years. There was a one-off loan set up fee of £63 and a £20 annual finance fee.

Following its introduction, the government expected that The Green Deal would be extremely popular. Britain’s housing stock was regarded as the worst in Europe in terms of energy efficiency. And although newer properties were being built with a greater emphasis on incorporating energy efficiency measures, older housing had insulation and heating systems that were woefully inadequate.

Rising energy costs and unstable world economies meant that Britain had to do something to use fuel more efficiently. Rather than address the issues that were compounding rising energy costs, the government sought to push the burden of improving poor housing onto the energy consumer.

However, problems started to arise. Getting an initial energy assessment took time and waiting lists developed. There was confusion in relation to who was authorised to carry out the improvement measures, and how the energy companies could also act as repayment collection agents.

Unscrupulous installers came onto the scene, carrying out improvements prior to assessments, getting householders to pay up front with the promise of obtaining later Green Deal funding.

However, perhaps the biggest concern of most potential Green Deal householders was the fact that although the home improvement measures might see their energy usage fall, it would be many years before they started saving money.

Another problem was that energy usage varied between families due to their own particular behaviours. Perhaps the best way of saving energy was for householders to look at the way they were using energy. As a result, many energy users simply modified their energy usage, cutting back to reduce bills. This of course was and still is, a problem for energy suppliers whose profits started to be affected.

A final problem was that many householders felt that although having an energy efficient home might attract a buyer in the future, having the burden of efficiency measure repayments collected on future bills by a new homeowner might not do.

Faced with disappointing take-up, the Government took the decision to effectively scrap the scheme. In July 2015.

The National Audit Office conducted an independent audit. Its findings, published in April 2016, revealed the Green Deal loan scheme only funded 1% of energy efficient measures. It also found that the scheme saved only negligible amounts of CO2 and that households did not see these loans as an attractive proposition.

It also found that the scheme cost British taxpayers nearly £400m and did not deliver energy or carbon savings.

The few people that did enter the scheme are left with the legacy of outstanding loans continually being collected through their energy bills. Initially, the loans carried penalties for early settlement of the debt.

In May 2014, the Green Deal Finance Company announced that it was cancelling early repayment fees for new loans. For those who entered the scheme prior to that, the loans can be paid off, but will occur a fee if the loan was for a sum greater than £8000 and over more than a 15 yr period. Loans of less than £8000 and for less than 15 yrs do not incur early repayment fees.

Following the decision to close the scheme, the Energy Secretary, Amber Rudd, said she was seeking funding for a new scheme for energy efficiency funding in Autumn 2015. This was then postponed until early this year. That has now been postponed until 2017 at the earliest.

With the prospect of any future energy efficiency projects aimed at homeowners looking doubtful, it is unlikely that those who are able to pay upfront for improvements are likely to be concerned. For those seeking finance, there are many deals that offer a far better package than the Green Deal did with all its complexities.

It may be that with rising concern about the plight of those living in fuel poverty, the Government will continue to focus its projects solely in favour of them.

Combi Boiler. System Drainage.


Occasionally it may be necessary to drain down a combi boiler and central heating system. This may be to facilitate maintenance procedures, cleaning the system or the addition of extra radiators.

The process is relatively simple, but prior to attempting to drain a system, it is advisable to ensure that the person carrying out the draining also knows how to re-fill, add inhibitor and pressurise the system once the work has been carried out.

The method of pressurising of a combi boiler system varies between model and manufacturer. Instructions for pressurising may be found in the boiler user’s manual.

It is important to note that if the actual boiler requires draining, this must only be carried out by a competent person. Draining a combi boiler system does not involve draining the internal part of the boiler.

Before draining the combi boiler system it is important to ensure that the mains electricity supply to the boiler and any system programmers are turned off. This is to prevent the boiler operating with an empty system, which could seriously damage the boiler.

It is not necessary to turn off the mains water supply when draining a combi boiler system.

To drain the central heating system, first, locate the drain tap. This will be on the ground floor or the lowest point of the system. Occasionally it will be conveniently located at the end of a leg of pipe leading from a radiator to the outside of the property. If not, a length of hose will need to be attached to the spigot and run to the outside of the property or to a ground level drain entrance.

With the drain tap opened, water should start to flow out of the system. This flow will need to be supported by opening up the bleed valves on all the radiators attached to the system, starting at the top of the property or the radiator furthest from the drainage tap. Air entering the system will replace the vacating central heating fluid.

With the system drained, now is a good time to flush through the central heating system to remove debris. This is best accomplished by engaging the services of a specialist company, however, some sludge and debris can be removed by operating the refilling device to allow water to flow through and out of the system. It will be necessary to close off the radiator bleed valves to facilitate the flushing through of upstairs radiators.

Once any maintenance work has been accomplished, the system can be refilled and pressurised.

Firstly, the drain tap should be closed off. It is then essential to go round all the radiators and close off the bleed valves using the radiator bleed key.

At this point, it is essential to add an inhibitor solution into the system. A good way to do this is to locate the plug at the top of one radiator. This plug will be at the opposite end to the bleed valve. Removing this screw threaded plug will reveal an opening into which the required amount of inhibitor can be added using a funnel or open-ended tube.

The correct amount of inhibitor required by the system can be calculated by using the information supplied with the inhibitor.
Do not forget to replace and firmly tighten the radiator plug after adding the inhibitor.

Water should now be allowed back into the system using the filling loop or the refilling device appropriate to the particular boiler. This may be a key type facility, which operates an internal valve system within the boiler.

As water re-enters the system, the pressure gauge on the boiler should start to register an increase in system pressure. If it does not, immediately close off the filling loop and check the entire central heating system for any leaks. It may be found that a bleed valve on a radiator has not been closed off correctly or some new work on the system is leaking.

When the pressure indicator on the boiler reads one bar, the filling loop should be turned off and all the radiators bled to remove trapped air in the system. The bleed valves on the radiators should be bled from the nearest radiator to the boiler along and up to the radiators upstairs, or the furthest from the boiler. It will be necessary to return to the boiler filling loop and re-fill the system after bleeding the air from each radiator.

With all the air removed from the system, the filling loop should be operated to pressurise the system up to the manufacturer’s recommended cold pressure operating level. This is usually between 0.5 and 1.5 bar.

Once the correct pressure is reached, the boiler power, the programmers, and the timers can be turned back on.

The boiler and central heating should now operate correctly. Any banging or loud gurgling sounds will indicate that air is still trapped within the system, as will any radiators that are hot at the base but cold at the top.

To remedy these situations, the radiators will need further bleeding to remove the trapped air.

To clean a combi boiler system, the process is similar to that described above.

First, drain down the system. Flush through with clean water. Refill with water and a suitable cleaning fluid such as Fernox. Re-pressurise the system and run for 48 hours. Drain down the system again. Flush through with clean water and refill the system with inhibitor. Finally, re-pressurise the system.

Before undertaking any DIY work on a combi boiler central heating system, it is advisable to check that the work will not invalidate any warranty on the boiler that might be in place.

What is a Passivhaus?

If you are like me, you have probably become very energy conscious. Conscious about the increasing cost, conscious about the environmental impact of obtaining energy and using it and conscious of not being able to afford to use it, full stop.

It was interesting to note that British Gas recently reported a fall in fuel demand for last winter. They attributed this to a mild winter. I do not recall the winter as being particularly mild. Rather it being not as cold as some. Winter is generally cold.

I doubt I am alone when I really do have to consider very carefully when, or indeed, if, I turn on the central heating at all.

Current energy policy in the UK seems to focus on supplying a potential for increasing energy consumption through investment in renewables and the development of controversial energy techniques such as fracking.

Increasing domestic energy costs to fund the development of intermittent energy sources and the exploitation of ever-diminishing fossil fuel reserves, may have the undesirable effect of reducing domestic energy consumption.

This causes untold misery for countless households that have little alternative other than to live in buildings that, by design, are not particularly energy efficient. Even new homes that are being built today and marketed as zero carbon are still significantly less energy efficient than a Passivehause.

A Passivehause, or passive house, uses innovate design and building materials to minimise energy consumption, reducing it to almost negligible levels whilst maintaining enhanced comfort levels within the building.

First developed in Germany in the 1990′s, a Passivehause works with its environment rather than imposing upon it. The building is specifically designed to be rigorously energy efficient. This allows it to conserve heat rather than relying on a constant supply of energy to maintain a comfortable living environment.

Building a Passivehause requires a complete shift in the current and traditional approach to building design and construction methods. Each passivehause must be individually designed from the ground up, and it must also take into account its location and the surrounding environment.

Using intelligent design in conjunction with a specialised computer software package, The Passive Hause Planning Package (PHPP), building designers and architects can fine-tune their designs.

Imputing various characteristics into the programme helps the designer to manipulate and modify the structure to maximise the energy efficiency of the building.

Although there are no set standards that must be adhered to, a Passivehause relies on a set of voluntary performance standards that accommodate many different ways of meeting the criteria for the Passivehause classification.

The design of the building requires that no thermal bridges are present in the construction. Thermal bridges conduct internal temperatures to the external environment and vice-versa.

Window construction must be of a superior design, typically triple glazed, filled with argon or krypton gas and the frames bonded into specialised insulation material to prevent heat transfer. The windows must provide a U-value of less than 0.8.

The building has to be encased in a quality insulation material, usually 300mm thickness and the building must be built to create an airtight internal environment. Some specialist insulation materials contain internal air pockets that enhance the insulation capabilities.

The building must optimise the heat from the sun and retain it along with heat generated by the activities of the occupants.

Ventilation is provided through a manual ventilation heat recovery system (MVHR) which must reclaim a minimum of 80% of the heat from extracted air and transfer that heat back to incoming air via the heat exchanger.

In order to meet the standards required for a building to be classed as a Passivehause, the heating requirement of the building must not exceed 15kWh/m/yr. In comparison, the maximum heat requirement set for a zero carbon new home for 2016 is 46kWh/m/yr.

The air changes in a Pasivehause must not exceed 0.6 times the entire house volume in one hour.

Consequently, the complete heat requirement of a Passivehause can be met by a small space heater supplied by a ground source heat pump and supplemented by solar energy. However, supplementary heat can be provided by gas boilers so long as the maximum kWh requirements are not exceeded.

Of course, each building will have different requirements dependent on the position of the building and the environment in which it is built. Building a Pasivehause at a latitude above the 60 line (London 51L) will increase costs due to greater insulation requirements and added design features such as underground heat storage facilities. This underground facility can reverse the conventional ground source heat pump technology to conserve summer heat for winter usage and vice-versa.

In general, the basic design and building costs are increased by at least 10% above conventional building costs. However, considerably more time is spent in the design process than current buildings require. Construction time is often minimised by the utilisation of pre-fabricated components.

Perhaps one of the most interesting facets of a Passivehause is the required change in the of the behaviour of the occupants. Any desire to open windows, such as for sleeping at night time has to be removed.

Once built, a Passivehause cannot be modified by expanding it, or by building extensions to it. Even fitting a satellite dish would seriously interfere with the structure by creating a thermal bridge. The occupants need to treat the building as a machine and co-exist with it.

Although not a particularly practical idea from a construction and financial position, it is possible to achieve Passivehause status in the renovation of an existing property, but in general, it is more economical to plan and develop one from scratch.

Nevertheless, as an alternative solution to energy concerns, a Passivehause construction produces superior comfort living environments for occupants at miserly energy consumption levels.

Passivehause status can be confirmed and certified by the Passivehause Institute following subjecting the property to a number of tests, but in practice, few Passivehause owners require that confirmation.

The principles utilised in domestic Passivehause construction can also be transferred into the design and construction of industrial facilities.

Great news for energy consumers, bad news for energy suppliers and governments.

 

Gas-Fired Absorption Heat Pumps

Whilst high-efficiency gas condensing boilers are currently the norm for new domestic water-heating installations, an attractive alternative is currently under development.

Heat pumps, in general, have slowly gained acceptance in the UK. The practice of extracting ambient heat energy from the environment and then concentrating it into a usable heat source has been around for many years. However, in the early days, the size of the equipment required for the process limited its application to the heating of commercial or large building structures.

Gradually, technological advancements enabled the size of the installations to be dramatically reduced, making them suitable for domestic utilisation. The move towards promoting renewable energy alternatives ensured that the uptake of heat pumps and the research into more efficient systems continued.

Vapour compression heat pumps are now becoming widely used in domestic situations to provide under-floor heating and supplement domestic hot water supply systems.

Although the installation of vapour compression heat pumps marks a considerable leap forward in attitudes towards reducing CO2 emissions and reducing fossil energy consumption, there has still been a level of concern about the use of HFC refrigerants as the internal heat transfer medium. Concerns about the escape of HFC compounds into the atmosphere have acted as a deterrent when considering the installation of heat pumps.

In addition, the need to compress refrigerants in vapour compression heat pumps requires electricity to operate a compressor. This reduces the overall energy efficiency factor.

Vapour compression heat pumps are designed to provide lower temperature background heating through a large surface area heating element that heats from ground level upwards.

Conversely, a condensing boiler produces high-temperature water that circulates through the relatively small surface area of radiant and convection heat emitters.

What is needed is a heat pump that can extract sufficient heat from the external ambient environment and convert it into a high-temperature energy source. This could provide copious domestic hot water at the required temperature plus enough surplus heat to power the installed central heating system.

Gas fired heat pumps are likely to provide the solution. They have been used extensively to heat large buildings. Now they are being developed and pioneered as the appliance that could consign condensing gas boilers to history.

Unlike their vapour compression counterparts, gas fired heat pumps use natural gas as a heat source to drive an extremely efficient heat collection and transfer system.

The principle at the heart of gas-fired heat pumps is the process of using a generator-absorber heat exchange cycle.

In this cycle, ammonia is used as a refrigerant or generator, and water acts as an absorber in the process.

A gas burner heats a water and ammonia solution contained within a closed loop system. This evaporates the ammonia, which turns to a gas. The ammonia gas under pressure passes into a condenser. In condensing, it releases heat, which is recovered to supply the domestic system. In condensing, it also becomes low-pressure ammonia in a liquid form. This liquid ammonia needs to evaporate and to do so; it draws heat from the ambient external air. In doing so, it becomes absorbed back into the water and returns to being a water-ammonia solution. This continual process powers the operation acting as a pump.

Because of this mode of operation, the system has no moving mechanical parts. This means that maintenance is negligible. It also means that the system operates quietly and unobtrusively.

The heat recovered from this process is considerably higher than the gas heat input required to operate the burner. The process delivers hot water in excess of 65 degrees centigrade. This is quite adequate for all domestic requirements.

The advantage over a condensing boiler is that the hot water has been produced by using a fraction of the amount of gas that a condensing boiler would use to provide the same heat output. Where condensing boilers are described as being up to eighty percent efficient, gas-fired heat pumps offer an efficiency factor of around one hundred and forty percent. The cost savings in energy consumption are therefore quite significant and it is hoped that the installation of a gas-fired heat pump will pay for itself within five years.

Even though the performance of gas-fired heat pumps is affected by changes in the external ambient temperature, they can still operate quite effectively at sub-zero temperatures.

It is possible to reverse the process to supply a highly efficient cooling system that can be operated during the hotter months of summer.

Although they can be used to extract heat from a ground source and other environmental heat retaining mediums, gas fired heat pumps are particularly suited to collecting heat from the air. As such, they are designed to be sited externally. The new versions starting to enter the domestic market can be freestanding or attached to the building.

It is hoped that eventually they will provide a suitable replacement for condensing boilers that have come to the end of their working life.

Because of the high heat output and the method of operation, gas fired heat pumps can be plumbed into any already installed heating system. It is likely that they will eventually form part of the ongoing process of the retrofitting of technological advances in the manufacture of water heating and control systems into existing installations.

Gas fired heat pumps are still in the process of further development. It is likely that as time progresses, purchase and installation costs will reduce and heat transfer efficiency will increase. However, gas-fired heat pumps are likely to rapidly become the accepted replacement for condensing boilers.

 

 

 

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.

 

 

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.

 

 

 

 

Micro CHP Boilers

So. You’ve just upgraded your old central heating boiler to a brand new, highly efficient condensing combi boiler and you’re feeling pretty good about it. It came with an excellent warranty and service package and you’ve been advised that the central heating, the remote access control system and the sophisticated programming features are all examples of the latest technology.

Then your neighbour gleefully informs you that he is planning to install a micro CHP system. This naturally deflates your buoyant demeanour and sends you scurrying to the internet to see what advantages your neighbour might be obtaining.

Combined heat and power (CHP) boilers have been around since the 1970s. Due to their size, weight, cost and operating noise, they have generally only been suitable for industrial and large communal facilities. They have been installed to primarily generate electricity, usually by internal combustion engines and dynamos, with the secondary heat by-product being utilised for central heating purposes.

In recent years, technological advances, spurred on by rising energy costs, have enabled the concepts of the commercial CHP boilers to be adapted for domestic operation. These new compact and vastly superior devices are referred to as micro CHP boilers.

Although much of the technology is still in the developmental field, some micro CHP boilers are available on the market.

Current models are similar in size to a large domestic condensing boiler and are wall mounted. They are also plumbed into the central heating system in much the same way. They do require installation by a Gas Safe engineer and a Micro-generation Certification Scheme (MCS) approved installer. What makes domestic micro CHP boilers special is that in producing heat for domestic hot water and central heating, they also use the heat to generate electricity for the home. Any surplus electricity is then directed back into the grid. The boiler owner receives a payment for the electricity produced for domestic use and also a payment for surplus electricity fed back into the grid.

At first sight, it can all appear very attractive, and no doubt, the neighbour has seen this as an opportunity too good to miss.

There can be no doubt that electricity produced from a remote power station is a dirty, inefficient fuel. Only about 30% of the energy from the source fuel is actually available to the consumer. The rest is lost in production and supply.

Being able to produce electricity at the point of usage has great advantages and can provide energy efficiency levels in excess of 90%.

The vast majority of micro CHP models currently available employ the actions of a Stirling engine to generate electricity. Stirling engines are classed as external combustion engines. They utilise the properties of internal chambers filled with a gas, usually helium. This gas is responsive to areas of hot and cold within the chambers. Applying heat to the gas causes alternating pressures as it moves to a colder area, and vice-versa. This movement operates a displacer and piston. The piston moves up and down inside a copper coil at around fifty times a second to produce electricity, which is fed into the domestic electrical supply.

The Stirling engine generates about 1 kW of electricity as it operates.

Because these boilers use gas in a very controlled and efficient manner, the general idea is that the Stirling engine should operate continuously using small amounts of gas to efficiently generate electricity, and supplement the domestic central heating and hot water supply, with a boost heating facility to raise the hot water system to demand levels.

Every electrical kW produced and used by domestic consumption receives a payment from the energy supplier. This acts as an inducement to produce electricity and as a payment for not using the supplier’s inefficient electricity source. On top of that, any surplus electricity is directed back into the grid and receives a FIT payment (the Feed In Tariff) from the provider for each kW produced. The micro CHP boiler must be installed correctly by an MCS installer to qualify.

So where are the pitfalls?

The major drawback is the cost. Currently, purchase and installation costs are in excess of £5000. The life expectancy of models on the market is around ten years. With gas and electricity fuel prices so volatile, it becomes difficult trying to assess whether, or when, the capital expenditure and the interest payments on any financial assistance packages would justify installation.

There have been calls for a substantial increase in the FIT to make installation of micro CHP boilers more attractive, but as yet, there has been no movement on that proposal. As such, any financial advantages are likely to be very modest over the long term.

Perhaps the main obstacle for installing current micro CHP boilers is the situation in a potential buyer’s home.

Householders have responded favourably to Government incentives and environmental concerns over recent years. They have improved insulation and many have installed a variety of heat saving devices. Some have adopted technologies that supplement heat requirements with heat recovered through accumulators.

The amount of gas that is required to heat a well-adapted home is now significantly less than in previous times.

However, demand for electricity is increasing. Households now require constant electricity, not constant heat.

The 1 kW electrical output of a micro CHP boiler with the current FIT and kW subsidy does not make the installation of the boiler a realistic proposal at the moment.

The future for micro CHP boilers is, though, looking good. Manufacturers are developing superior alternatives to Stirling engines. Ceres are developing fuel cell technologies that will revolutionise domestic heat and electrical production. Within these fuel cells, heat and electricity can be generated without combustion removing all the problems associated with it.

Hydrogen cells are being developed to utilise the energy produced by micro CHP boilers and other green energy generating technologies. Hydrogen can be produced by surplus electrical activity and then used to generate electricity again at peak demand.

These green and clean modifications incorporated into, or complimenting micro CHP systems will make installation more of an attractive proposition in the future. The electrical kW output produced is much greater. Already the major energy companies are voicing disquiet about the possibility and implications of millions of micro energy producers feeding surplus energy back into the grid. And with some justification!

Perhaps lots of micro energy producers supplying a local network might be the answer to the ailing, aging and costly grid network, in addition to the public’s growing disquiet about the energy company’s extortionate energy generating profits.

In the meantime, compliment your neighbour for considering becoming a torchbearer and protagonist of nascent technologies.

 

Gas and other Energy Saving Tips

Although recent world-wide gas and oil commodity prices have seen unprecedented falls, as North Sea gas supplies start to dwindle and the United Kingdom is obliged to compete with a growing demand for gas on the global markets, it would seem that the long term outlook for household energy bills is likely to forecast sharp price increases.

More and more, householders are being forced to examine their fuel usage and look for ways to economise and live within their tight budgets.

However, economizing is not necessarily a euphemism for austerity. On the contrary, it is more about using energy sources wisely and efficiently. It is about extracting as much benefit as possible from each hard-earned pound spent on fuel and minimising expensive waste.

It can also be quite encouraging, especially when using energy usage monitors. It is very satisfying to watch domestic fuel consumption drop in response to a few minor changes to the home and to the occupant’s behaviour.

Energy saving appliances are all well and good but the way they are operated has a greater bearing on economy than might be imagined.

Likewise, loft and wall insulation coupled with triple glazing may help to prevent heat dissipation through the fabric of the home, but it will not prevent draughts from unshielded keyholes or open fire chimney vents from sucking that expensive heat into the cold outdoors.

So, if you have uncovered a previously boarded off fireplace and discovered a rustic Victorian cast iron focal point, make sure the chimney is capped off or buy a dedicated chimney balloon that inflates to fill the gap.

Fit letter box brushes, keyhole flaps, check door seals and ensure that the traditional wooden floorboards and old skirting boards that have been revealed to add character to your home are sealed to plug gaps. Warm coloured fitted carpets are good insulators. Seal the gaps where pipe-work exits through walls, however, take care not to block any air vents.

Good, heavy and thickly lined curtains, properly hung, are excellent insulators but during even the coldest day, the sun is a great source of extraneous heat so let the sunshine in.

Fitting reflective foil behind radiators can prevent heat being lost through walls behind them.

Move furniture around so that you are not sitting next to exterior walls.

A tropical living environment is great for shorts, T-shirts, iced beer and lethargy, but not so forgiving on the household fuel budget. Thermals, chunky polo neck sweaters and cups of steaming tea are far more nostalgic, as is dropping the thermostat a few degrees to bring back an equally nostalgic and retro style fuel bill.

A cool bedroom is great for a good night’s sleep. An electric under blanket ensures a cosy bed to fall into no matter how cold the weather is outside.

Upgrade central heating controls and install a multi-function programmer for a more dedicated system of home heating management.

Gas as a fuel is considerably cheaper than electricity. Solar, wind and heat accumulation sources are currently free. It is therefore advantageous to invest in technology to exploit these natural resources to compliment gas and electrical energy consuming appliances.

When cooking on a gas or electric hob, anything cooking in boiling water is immersed in that liquid at 100C. It does not matter how high you turn up the regulator setting, the water in the pan will never rise higher than boiling point.
Any extra heat surplus to that required to maintain a gentle, rolling boil is energy wasted. A flame or heat source that extends beyond the circumference of the base of the pan is also wasted energy. Make sure the gas flame is crisp and blue. Yellow colours indicate inefficient combustion.

Pilot lights can use 40% more energy than electronic ignition.

Putting lids on pans and using pressure cookers saves time and energy usage. Try turning off cooking appliances a few minutes before food is ready and allow cooking to continue on the residual heat. Oven doors rack up the running costs when opened frequently during cooking. A quick peek can drop the oven temperature by 20%. Keeping the glass viewing front clean will prevent the need to open the oven door.

Likewise, excessive opening of fridge and freezer doors when pondering or grazing, gnaws away at energy efficiency targets.

Low flow shower heads and reduced time showering can make a big difference to hot water usage. So can fixing dripping hot taps or refraining from washing and rinsing under a flowing hot tap.

Washing machines will now operate effectively at much lower temperatures due to the introduction of low temperature washing detergents. A full load is the most economical way of operating the machine.

If a hot water cylinder is installed in the property, setting the thermostat to 50C can usually satisfy the temperature requirement of the domestic hot water supply. An adequately insulated cylinder will also conserve the temperature of the heated water.

Keeping the boiler and central heating system in top condition is a must for ensuring gas is utilised efficiently. Anything that impedes the efficiency of the system is likely to reflect quite dramatically on the energy bill. Small inefficiencies combine over a short period to inflate energy costs and most of these can be rectified or eliminated quite easily.

Reducing energy costs can become a healthy compulsion and with practice, may eventually lead to the disconnection of the energy monitor itself, thus saving a few operating watts of electricity and representing the epitome of gas and energy efficiency.

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.