Archive for the ‘Diy’ Category

A Powerflush (or power flush) is an efficient way of removing the sludge and dirt that build up inside your central heating system over time. Without a Powerflush you could see a gradual reduction in efficiency of your boiler system as this sludge coats the internal piping and reduces circulating efficiency.

Most central heating systems develop this sludge over time, there will be more in powerflusholder systems. You do not want to replace and update your boiler with the latest model without commissioning a Powerflush first. As the sludge and general dirt are disturbed in the new installation it will find its way into your new boiler and reduce its effectiveness or life span.

The following are some of the problems that could be avoided with a Powerflush as it removes the Magnetite sludge from your system : –

  • Cold Radiators
  • Boiler Deposits
  • Heating Pump circulation problems
  • Pipe Blockages
  • Internal Corrosion
  • System blockages
  • Noisy systems

As a result the benefits of a professionally delivered Powerflush could be :-

  • Increased pump life as your central heating pump handles clear water instead of sludge
  • Curing radiator cold spots so that the full surface of the radiator heats your room
  • Improved central heating system efficiency so reducing fuel costs in future years.
  • Clearing the boiler heat exchanger to stop banging noises (kettling) and prolonging the boiler life
  • Reduces Hydrogen gas build up which can lead to radiator corrosion and reduced heat output
  • Clearing your system of contaminated water which could lead to internal heating system corrosion.

A Powerflush machine is used to complete the task. It is connected to your system and the central heating water is routed through the machine where it filters out the contaminants. The Powerflush literally flushes the new liquid through your central heating system. Once the task is completed the Engineer should refill your central heating system adding a corrosion inhibiter to prolong its operating life.

A Powerflush needs to be performed by trained engineers and there will be no mess or complicated installations. The Powerflush machine connects to your existing piping enabling the task to be completed rapidly, it can then be de-coupled leaving your heating system as it was, minus the sludge.

The heating controls in your central heating system are designed to allow you to control the temperature of your home and to use energy efficiently. For the controls to be effective you should be able to turn them on and off and they should rapidly react to any changes in room temperature. If you have thermostatic heating controls in each room they should provide varying levels of heat in different parts of your home, at levels set by you, and stop your boiler from working when it is not needed.

The main parts of your heating system are:-

Radiators enable the heat in the hot water generated by your boiler to be released into a room through convection of the surrounding air. So that the room is not too hot or too cold the radiator should be appropriate for the size of the room and if you have a new central heating system each room will need to be assessed. You should ‘bleed’ your radiator if you notice it is not as warm as it should be. Radiators also have valves to restrict the flow of hot water (see the section on valves and thermostatic valves below).

radiator valveRadiator Valves. Valves are provided in radiators to enable you to shut off or restrict the flow of water. This can be in an emergency following a water leak or when you wish to remove or replace the radiator. Turning the valve in a clockwise direction should close down the flow and turning anticlockwise will restore the water flow. If you plan to remove the radiator you should also close the valve on the other side of the radiator to completely seal it off prom the main plumbing.

Thermostatic radiator valves (TRVs). These act similar to radiator valves but they also control the temperature ofthermostat valve each room separately. To achieve this they sense the room temperature and reduce the flow of water into the radiator when it reaches the required temperature. They tend to work best in rooms which get too hot or are used infrequently. As they work independently of the main room thermostat you can achieve a more precise control of individual room temperatures and hence reduce energy consumption.

Programmers or time-clocks are the most useful controls for controlling the temperature programmer imageand energy usage. They can they turn your heating and hot water on and off depending on the times you set. More advanced programmers can have a different on / off pattern for weekdays and for the weekend. To be fully effective they should be capable of controlling the heating and hot water independently so that, say in the summer, you can still have hot water when the heating is off. Of course if you have a combi boiler then it produces hot water on demand so you need only be concerned about switching off the heating. Also look for the ability to advance a cycle and immediately turn on either the heating or the hot water without disturbing the programmed schedule.

Room thermostats automatically switch your heating off once the chosen temperature is reached and bring it back on if the temperature in the room falls. To save energy you should set thermostat imageyour room thermostat to the lowest comfortable temperature. In domestic properties this is usually 18°C – 21°C. It is surprising to learn that lowering a thermostat by just 1°C can cut up to 10 per cent off annual heating bills. A thermostat controls the temperature of the air in the room where it is positioned. They need a free flow of air to detect the ambient room temperature, so they must not be covered by curtains, blocked by furniture, or positioned near to drafts and direct sunlight or other sources of heat. You should also not put a thermostatic radiator valve on the radiator with the room thermostat or the operation of the two thermostats will interfere with each other producing unexpected effects.

A well maintained gas appliance will produce, dioxide as a normal byproduct. If you save money on the annual servicing for the appliance you run the risk of carbon monoxide being produced. The underlying reason for this is that gas appliances are designed to operate with a certain volume of oxygen. If the ventilation is obstructed for any reason the level of oxygen in the combustion process can decrease and appliance suddenly turns into a killer.

With high standards of boiler servicing and strict ventilation regulations the number of people killed by Carbon Monoxide has reduced to 30 people each year although many more are seriously injured.

Can I visually check my gas appliances to see if carbon monoxide could be a problem?

One way of having a simple look for potential combustion problems is to investigate for signs of staining, soot or dirty marks on or around gas boilers, fires and water heaters. You can also check pilot lights and other gas flames that normally burn blue through an inspection chamber if fitted. If the flame changes from blue to yellow or orange this could mean that carbon monoxide is present and you should have the appliance inspected by a professional.

How can I look after my family?

As mentioned carbon monoxide gas regrettably is produced when a gas flame burns without the right amount of oxygen in the surrounding atmosphere. Assuming that a ventilation audit of your proposed installation was completed before your boiler was fitted the best defense to this is the regular and expert servicing of any gas appliances that you have including your boiler.

Make sure your central heating boiler is maintained annually by a CORGI-registered engineer. As a second, very important, line of defense, fit a British Standard approved carbon monoxide detector with an audible alarm.

Whilst it might be tempting cover cold air vents in the middle of winter, as they are creating draughts, this would be very foolish and they most be kept open. Also regularly inspect for plants which might be growing near a vent outside as over the course of a year they can also block them. And also take particular care that your chimney doesn’t become blocked with birds’ nests or other debris.

What are the early signals of carbon monoxide?

Caution, caution, caution of the bywords if you suspect production of carbon monoxide. Do not read this website and its postings or other articles and then declare yourself and fax it to adjudicate upon carbon monoxide issue. Take action to protect yourself and your family quickly.

Any person in your family can suffer the effects of carbon monoxide no matter whether they are young or old. This also applies to household pets. The symptoms exhibited by carbon monoxide inhalation can often be confused with other flu like illnesses and include:

persistent headaches
extreme tiredness

If any of these symptoms occur, particularly when using a gas heating or a hot water appliance, you should immediately stop using the appliance, open the windows to improve ventilation, get family members out of the house and get the appliance checked by a CORGI registered engineer.

Can anyone get a detector on the high Street?

Recommended detectors are certified to stringent British Standards and have an audible, very loud alarm. Fine year battery lifetimes are a good future with a test facility to ensure that the alarm is capable of giving a loud early signal.

Less effective detectors work on the principle where a coloured mark on the detector paper changes colour over time when dangerous carbon monoxide gas is detected. these are the detectors of choice and have a limited lifespan, typically six months. This means that you need to make a note to substitute them regularly. Most importantly they do not have the very loud alarm and will not wake you is there is an excess of carbon monoxide produced when you are asleep at night.

When your central heating system is installed the installer should have carried out a survey to ensure that there was sufficient working ventilation to the boiler. Modern condensing boilers are very safe provided that proper care and attention has been paid to the ventilation in the room and that the boiler is serviced regularly. If they are not installed correctly then many problems can arise from the less problematic costs of inefficiency through to the fatal risks of carbon monoxide production.

There are some safety matters relating to ventilation that you can carry out yourself and you should perhaps make a note to carry out a visual inspection of your systems ventilation, say quarterly, to keep your family safe. If you rent a property it is your landlords responsibility to ensure that the gas appliances and pipework are safe although this should not stop you having a look for yourself.  If you go on holiday and the property has a gas boiler, eg a regular boiler, do not be afraid to ask the letting agent when the boiler was last serviced, there are too many stories in the media about families that suffered the consequences of carbon monoxide poisoning from a badly maintained boiler.

boiler ventilationBoiler Ventilation

Whilst it is hard to believe, the picture on the left is a real boiler with a climbing plant clinging to it. The problem with plants is that they can grow very quickly and they need pruning every year, the best approach is to keep them well clear of any gas boiler.

This illustrates the need to keep your gas appliance vents and flues free from any garden foliage and other blockages which can develop over time. Failure to do this will make your heating inefficient at best and could result in you putting your family at risk of poisoning from deadly carbon monoxide gas in the worst case scenario.

Flue Ventilation

You should also ensure that nothing on the outside of your property has blocked the flue of the gas boiler.

The boiler flue is designed to help the boiler exhaust gases to escape to the outside whilst the boiler is working. Some boilers also have a small fan within the flue to assist this process and expel gases for a short while when the boiler has closed down.

During the year, unrecognised by yourself, some plant growth or storage of garden materials may block the vent making your heating

If you have an open flue boiler you should be aware that new regulations will be introduced 1 June 2008. After that date any open flue boiler which has less than 90 percent of the required ventilation will be classified as a potential risk.

If a boiler is operating inefficiently it could be emitting lethal carbon monoxide gas and you would not know it. Fortunately there are carbon monoxide detectors sold which are small battery operated devices which can be placed within the room that houses you’re boiler. If there is a problem and carbon monoxide is suddenly produced the detector will emit a loud audible alarm alerting you to the problem so that you can get your family to safety quickly.

Without care and ongoing maintenance your new central heating system will gradually deteriorate over time as impurities build up within the circulating water. Every day water is circulating through the hot water pipes and all of the radiators. If there or impurities get into this system they can lead to chemical changes within the pipes and the circulating water which can lead to the build-up of debris or clogging of various components. Combi boilers are prone to the effects of building impurities and sludge within the system.

There are many products on the market which help to reduce the effects of corrosion and the build up of scale or sludge within your central heating system. These are often applied annually or every two years to ensure ongoing protection. You do not need an expert to do this as if products are simply added to the circulating water although the process of doing this is different according to which type of system you actually have.

If your system is severely sludged or if you regularly hear boiler banging you should first apply a product which will remove this contamination. A Powerflush can also help to remove these items and restore the water circulating within your heating system to its original condition. The Powerflush will need to be carried out by an experienced plumber as they will have the equipment and you will not.

After the powerflush you need to add corrosion inhibitor to the system. If you do not do this you have wasted your time and your money as the system could be back to the same level of corrosion in a short period of time.

In a conventional condensing boiler system this inhibitor can be added via the expansion tank which is often found in the loft. As the liquid within your heating system gradually expands and contracts the contents of the header tank will be mixed within the circulating water.

As an alternative you can add the inhibitor via a radiator. The inhibitor manufacturer should supply with the adaptor to enable you to inject the fluid into the radiator. Read the instructions carefully before you attempt this. if you are searching for these system protection products look for “Sentinel” or for “FERNOX” as these are some of the leading brands with proven products.

As with all maintenance requirements, a little tender love and care will keep your system running happily for many years to come and an efficient system will save on your heating bills. Overlooking the need to protect the circulating water within your central heating system could be a costly oversight, reducing the life and efficiency of the system both of which will cost you money in the longer run.

if you have a new central heating system installed or get a replacement gas boiler make sure that you ask the boiler installed what the system protection requirements are and when these should be applied to the system. The boiler manufacturers will make recommendations concerning this refinement and it is best that you diarise the dates when you should be checking the system.

Most condensing boilers and many standard boilers are now installed as Pressurised Systems. This differs from the previous conventional boiler systems which were reliant on a water tank (often in the loft) with a ball float device to maintain water levels within the system. As the self filling water tank is omitted a pressurised system requires filling manually via a filling device, ( a ‘filling loop’). This allows a specific amount of water to be injected into the system via your mains cold water supply.boiler pressure

This water pressure is distinct from the pressure in your hot or cold water taps. The pressure in your mains cold water taps comes direct from the water mains and is maintained by your water company. The pressure in your hot water taps is created by the head of water in your heating cylinder or from the pump feeding your hot water supply.

How can you tell what current pressure of the system is ?

Every pressurised system, regardless of the type of boiler (combination boiler, combi boiler or standard system), will incorporate a pressure gauge which you can read. This pressure gauge is the device with which the system water pressure in your boiler and radiators is monitored.

To maintain the system in a healthy condition the pressure gauge should be checked monthly. If when you check it, you find that the system pressure has fallen please follow the steps below to re-pressurise your system.

Your central heating system manual will advise of the pressure that your system runs at. Most systems should be pressurised to between 1 and 1.5 bar.

Topping up the system pressure

To top up your system and increase the pressure, you will need to locate your filling loop. It most usually resembles a stop tap and is connected to the central heating system by a metal hose. Occasionally you may find that one end of the this metal hose is not connected to the pipe work on your system. There may be a cap on the end of the pipe and it will need to be connected to the system to allow the water to be injected.

To connect the filling loop to the system, simply remove the cap from the end of the pipe work and attach the metal hose. You will then need to tighten this connection with your fingers, do not over-tighten with a spanner.

Sometimes this filling device may be hidden, behind a baffle near the boiler or perhaps inside a cupboard below the boiler. It will always be somewhere close to the boiler as it needs to be able to connect to the boiler pipework.

Another issue in finding the filling loop may be that some filling devices are an integral part of the boiler, you should have been advised of this by your boiler installer and you will need to refer to your boiler manual for the exact manner in which this system is repressurised.

If you have a Homecare contract don’t be too concerned if you can’t find your filling loop – ask the British Gas Service Engineer at the time of your next Annual Check.

To fill the system, use the tap you have located to open and close the filling loop. When the tap is opened it will allow fresh water to flow into your Central Heating system. As this happens you you will hear the water passing through the valves into the system. It is recommended that you open the valve slowly to allow the system to fill up gradually. When you do this a steady increase in pressure will be seen on the pressure gauge in the same way as you would see an increase on a car tyre gauge if you were inflating a tyre.

If you cannot see your pressure gauge while filling the system it is a good idea to have a friend look at it for you while you are turning the tap. When the recommended pressure is reached close the valve by turning it in the opposite direction to which you opened it.

There is no need to worry if your system does accidentally become over pressurised . All modern systems are designed with safety in mind and a pressure safety valve is incorporated into the plumbing. This acts like an overflow pipe releasing the excess pressure and allowing the system to revert to the recommended levels.

The safety valve may make a noise as it releases this excess pressure sounding like a thumping noise, again do not worry, this sound will stop when the system pressure reduces to a lower level.
If the system is free from leaks the water pressure should remain constant within the system in future months. If you notice that the pressure regularly falls you may have a pressure leak.

Bleeding radiators involving perhaps a small amount of air escaping from a system at the radiator bleed point can reduce the overall system pressure. As a result after bleeding your radiators you should remember to check your pressure gauge and fill the system as required.

Random water leaks will cause pressure loss within a pressurised central heating system and the severity of water leaks can vary. Very small leaks will cause pressure drops over a long time, possibly several months or even a year. Leaks of this magnitude may not be detectable as the water evaporates quite quickly although you may spot some residue following evaporation of the water.

Larger leaks may be more visible and will mean your system will require filling as frequently as once or twice a week. If this is the case you should check your system for leaks when it is cold paying particular attention to the areas around radiator and boiler valves. It is recommended that you check for leaks when the system is cold as heat causes expansion and can seal small leaks temporarily.

If the bottom of your central heating radiator is warm but the top is cold it means that the radiatorradiator bleeding image is malfunctioning and needs bleeding. Remember to take care and not burn your hand on the radiator when you are checking this. Bleeding is not a medical process but it is a way of getting care and of the radiator so that the hot water can properly flow through the radiator keep it warm and able to your property.

If the whole radiator is cool radiator despite the fact that the central heating system is on then it could be that the radiator is almost full of air. The air prevents the hot water circulating and no real difference in temperature between the top and bottom of the radiator will be experienced. This problem will contrast with the remainder of the other radiators in your central heating system which will be hot to the touch if they are operating normally.

How do I bleed a radiator at home?

The process for bleeding a home radiator is relatively simple and safe if you follow a few procedures. All radiators are supplied with a small bleed key. If you don’t have one they can be obtained cheaply from a local diy shop. Look carefully near the top of the radiator and on one side you should see a small protrusion called the bleed valve. To bleed the radiator you need to open this bleed valve a small amount. When you do this listed carefully and you will hear the air escape from the top of the radiator. Ensure that you do not allow the water to flow out as it could scald you or mark the carpets. Pay attention because at some point the air will have been fully expelled and will be followed by hot water. At this moment you need to be able to switch the valve off without delay.

If you decide you want to bleed a radiator in a sealed system you will first need to reduce the air pressure in the whole system (consult your manual for how to do this). Do remember that when you have finished you will need to top up the system afterward from the main cold water feed.

BE CAREFUL when turning the bleed valve. Have a small plastic bowl to catch any drops of water which escape and an old rag to shield your hand if required.

bleed radiator imageFirst switch off the heating boiler, failure to do this could allow more air to get into your system. Use the radiator bleed key to carefully turn the bleed valve counter-clockwise a small amount, 1/2 turn would be ample here. The air trapped in the radiator will start escaping with the hissing sound we mentioned – it is similar to a that in a bicycle tire. when you start to pump it up. When finally water begins to drip out of the valve you will know that all the air has been purged, and you can now carefully gently twist the bleed valve the other way to close it. Check for any leaks and then switch the heating back on and thoroughly check that there are no ongoing leaks from the radiator valve you have just bled. If there are check that you tightened it properly.

As we covered earlier check the system pressure and top up the water f the central heating system was a sealed system, if you have any problems consult your central heating system manual.

If you have followed the radiator bleeding process as outlined and it not seem to improve the operating performance of your heating, especially if several central heating radiators are malfunctioning, there may be another problem and you will need to call out a plumber.

How much do replacement radiators cost?

If you are searching for replacement radiators they can be purchased direct from suppliers for installation by a trained CORGI engineer. Some examples are illustrated below.

The following is the CORGI Membership Code of Conduct reproduced from the How can CORGI Help site

This Code represents the standards required by CORGI as a condition of membership. The code focuses on providing the consumer with both peace of mind and confidence in contracting a CORGI member to carry out work.

As a representative of CORGI the member will agree to the following:


•  Provision of a friendly, helpful and professional service to my customers at all times.
•  Be open and honest with customers and strive to meet the needs of customers with specific requirements.
•  Respond to customer enquiries when I say I will.
•  Explain my actions and decisions clearly to the customer.


•  Be accountable for my actions and take responsibility for what I and my business have committed to do.


•  Carry out consistently safe and competent work.
•  Always leave customers’ premises as I find them.
•  Provide fairly priced, written quotes, which are as transparent as possible, to the customer and ensure they fully understand the work involved.
•  Arrive at the times I have agreed with the customer or if I can’t, let them know within a reasonable time when I will be there.


•  Value and respect the diversity of my customers.


•  I understand I need to undergo continual professional development to ensure I can offer the most modern, most appropriate and cost effective solutions to my customers.

Customer Complaints:

•  Get things right first time. If I fail to do this I will put things right quickly and within a time frame agreed with the customer.

I hereby agree to comply with the standards set out above and have my work duly rated by customers as part of the CORGI rate an installer function.

As such you can have increased confidence when contracting a CORGI member.

The above information has now been superseded by the “gas safe” scheme. Essentially the safety requirements and knowledge prerequisites are very similar. We have mentioned this as in your online research you might come across the “gas safe” branding and wonder what that related to.