13 minute read
System cleaning and water efficiency
Don’t forget the basics
Everything you need to know about water treatment and how it can keep your customers’ heating systems running efficiently, preventing boiler breakdowns.
Even the most efficient gas heating system won’t stay efficient for long if the water that flows through it isn’t clean. Dirty system water can be full of sludge, limescale and magnetite that will clog up boilers and radiators, causing blockages, damaging system parts, and ultimately causing component breakdowns.
That’s why there are so many products to help improve system water quality and minimise the corrosion of metals in the system.
BS 7593:2019* sets out the correct ways to treat the heating system and encourages heating engineers to follow best practice and to treat the whole system rather than just the boiler.
Flushing
All new central heating systems should be flushed before they are first commissioned, and when a new boiler is fitted, to ensure the system water is clean. Flushing can be done using gravity to empty and refill the system, or by connecting a mains-pressure hose to the system and draining out the existing water.
After using water treatment chemicals to suspend, disperse and remove accumulated material, individual radiators on the heating circuit are flushed by opening/closing their isolation valves in turn, before flushing the whole system with all valves open. The system is then refilled, using inhibitor as required and returning all radiator valves to their previous settings.1
Engineers can also carry out a powerflush that circulates chemical cleaning agents through the radiators, pipes and boiler at very high pressures. This pushes out any existing sludge or deposits and clears the way for the system water to flow through without issue.
Test regularly
BS 7593:2019 requires heating engineers to test heating system water every year – ideally when the boiler is serviced – to check
that the water is still clean, and so that chemical water treatments can be added to tackle any sludge build up.
Clean it
Chemical cleaners help shift magnetite and sludge that have already built up in the system. The cleaners break down deposits into smaller pieces that can be flushed out.
Inhibitors
Corrosion will always occur when water comes into contact with metal. Once the system is clean, add a chemical corrosion inhibitor to the water to stop new deposits forming.
Inhibitors work by attaching themselves to the metal components inside the heating system, forming a protective layer between the metal and the water.
If left untreated, corrosion can cause system noise and pipework blockages, as well as forcing the boiler pump to work harder to force the water past the blockages, reducing overall system efficiency.
Filters
System filters are usually fitted to the heating system when a new boiler is installed but can be added at any time. Once fitted, the heating system water runs through the magnetic filter: any rust or corrosion is attracted to the filter and is removed from the water flow to collect in a separate chamber, where it can be removed by the engineer. Sludge-free water can continue to flow through the system without damaging internal components.
Deaerators and dirt separators
Deaerators and dirt separators can be added to remove air and dirt from the system. Dave Goodyer, area sales manager at Spirotech, says: “Many homeowners are still unaware of the impact that air and dirt can have on the efficiency of their heating system.” Installing a filter and air separator can help improve efficiency by up to 13 per cent, he says.
Flow temperatures
Some utility suppliers are advising customers to lower their boiler flow temperatures to help reduce energy bills. With forthcoming Building Regulation changes anticipated to recommend lower system flow temperatures, it’s even more important than ever to clean and treat the system water, especially when there is a hot water cylinder.
David Stanley, UK technical service manager at Intergas Heating Solutions, says: “Flow temperatures [should be set] according to the system design; ideally you need the system return temperature to be lower than the flue gas temperature dew point of 56°C.
“With a standard combi boiler, try starting with a flow target temperature setting on the boiler of around 60°C for the heating and 55°C for the hot water. Many homes have oversized radiators that allow you to run lower flow temperatures: however, it is critical that the radiators are balanced correctly and the system cleaned and treated to BS 7593:2019.”
However, it’s not recommended to do this with boilers that use hot water cylinders because the cylinder won’t be able to satisfy the higher temperatures and, crucially, necessary regular disinfection of the hot water tank could be affected.” ■
*BS 7593:2019 Code of practice for the preparation, commissioning and maintenance of domestic central heating and cooling water systems
HSE document L8 is the Approved Code of Practice and guidance for the control of legionella bacteria in water systems. It states that pasteurising should occur daily, for a minimum period of one hour at 60°C to ensure that legionella bacteria are eliminated.
Why clean heating systems can save money
Effective water treatments and heating system protection can play a valuable role in tackling rising energy costs in the home, says Craig Worth, national sales manager at BoilerMag.
Adramatic increase in the cost of wholesale gas this year has sent household bills soaring, with more likely to come in October. Households and businesses are feeling the pinch and many are looking for ways to boost efficiency and increase the longevity of their heating systems.
It’s estimated that around 9 million boilers in the UK are currently deemed inefficient, and that 80 per cent of heating system problems are largely caused by system contamination such as sludge and scale.
Boiler breakdowns and lower efficiency are commonly caused by corrosion of the iron and steel components in the heating system, which causes a build-up of iron oxide, or ‘black sludge’, contaminating the system water. This can easily block the boiler’s heat exchanger or boiler pump and accumulate in radiators.
The problem isn’t unique to older systems. Even newly fitted pipework can be subject to a debris build-up. With the enforcement of the forthcoming Part L Regulations and standards
such as BS 7593, effective water treatment solutions are about to become even more critical. With a laser focus on protection, cleaning and maintenance, there are many solutions to help combat the significant problems arising from energy problems in the UK.
Without a doubt, installing an inline magnetic filter will contribute to improved energy efficiency and combat the price hikes this year, as well as reducing costs for years to come. A quality magnetic filter technology helps to ensure that the vast majority of ferrous oxide is removed from the heating system effectively even from the first pass of the magnet.
The use of magnetic filters can help to maintain heating system functionality and cleanliness by protecting it from sludge, as well as cutting energy bills and significantly reducing the risk of boiler breakdown.
With several filters covering a wide range of heating systems sizes and budgets, the benefits of having a filter installed are indisputable. Both homeowners and business owners will be prolonging the life of their heating systems, with a proportionately small initial cost, as well as saving money on their energy bills at a time when everyone is feeling the pinch.
Once the problem of sludge management has been addressed, it is also important to tackle the age-old nuisance of limescale. Around 60 per cent of UK homes are in hard water areas, and a typical fourbedroomed house can accumulate around 70kg of limescale in just one year.
Limescale build-up can cause significant heat loss as deposits have a tendency to stick to heating components. Common symptoms including boiler kettling, reduced heat exchange, cold spots in radiators, increased energy costs, and boiler breakdowns.
A simple but often overlooked solution is an electrolytic scale reducer, which offers simple, cost-effective and long-lasting protection. The combination of a copper body and an internal zinc anode releases zinc ions into the water, which react with limescale particles and change their state. This process means particles are less likely to stick to key heating components, reducing the risk of blockages and limited heat exchange performance.
Stay clean
It’s important to remember that cleaning can enhance the longevity of heating systems and shouldn’t be overlooked. Cleaning chemicals are essential for the effective removal of limescale deposits, installation debris, and magnetite. Good quality, high-performance cleaning chemicals will display the Benchmark logo, which is an endorsement of the product’s reputation and associated back-up services. In addition to limescale and iron oxide dispersal rates, cleaning chemicals should be phosphate-free to avoid damage to pumps and bearings.
Inhibitors provide ongoing protection against corrosion and scale and should be used after a system flush or installation and re-dosed every five years. A high-performance formula will maintain heating efficiency and should be free from damaging or harmful chemicals such as borate and phosphate. Good-quality inhibitors will display the Benchmark logo and should be NSF approved*.
As we navigate through the precarious energy situation, consumers may feel that there’s little they can do to stop rising costs. However, there are ways in which industry professionals can help to reduce the burden on energy bills: ensuring that systems are safe, efficient and cost effective by taking preventative measures is one way to support them in these difficult times. ■
*www.nsf.org/gb/en
BoilerMag’s filters and treatments improve system performance and efficiency. The patented dual-flow technology in its magnetic filter collection effectively removes both magnetic and non-magnetic debris and comes with a no-block guarantee.
When used alongside the fit-and-forget electrolytic scale reducers, cleaning chemicals and inhibitors, the range provides protection against heating system nasties while improving energy consumption and component life.
www.boilermag.com
Why choose continuous flow?
When a stored water system or unit comes to the end of its working life, it is easy to assume that replacing like for like is the best option. But changing the same old for the same new isn’t always better, writes Rinnai’s Pete Seddon.
There is actually a huge and costly amount of work involved in replacing like with like: most plant rooms are limited in space, which means the old equipment needs to be removed before new appliances can be installed.
Easy access and continuous, limitless flows of hot water are critical components of building services for all applications in all sites. Continuous-flow technology in hot water delivery provides constant flows of temperaturespecific and controlled-delivery end-products that are ready for hydrogen blends and BioLPG. They are also a one-person lift requiring no lifting gear.
If the appliance being replaced is non-condensing and the new appliance is condensing, then the flue will probably need to be changed, as well as needing provision to discharge condensate.
Plant rooms are rarely designed to enable equipment to be removed easily, and having to do this before new equipment is installed would have a major impact – and it takes so much time.
No shutdown needed
Removing the hot water system means it has to be shut down completely to enable the work to take place and sites, especially healthcare ones, simply cannot allow this to happen.
The size and weight of these appliances can make life exceedingly difficult for installers. They are usually manufactured with enamel or glass-lined mild steel, which is both heavy and fragile. Several people are needed to manoeuvre them out and in, even specialist lifting equipment and cranes for higher plant rooms.
Continuous-flow solutions can make the entire process a lot easier. They weigh around 30kg, which is a one-person lift, and Rinnai’s appliances come in 47kW and 58kW, providing a large volume of hot water for a small appliance – 774 and 954 litres per hour at 50°C rise.
Appliances can be cascaded, which means that when more hot water is required, just add more continuous-flow water heaters. A single heating engineer can create a system that will produce vast amounts of temperatureaccurate hot water. There’s also built-in redundancy so that if one unit needs to be shut down, the site still has ready access to hot water.
Control the cascade
Plug-and-play cascade sequencing control systems automatically control how many appliances are running at any one time: just plug it in and choose the primary water heater.
Continuous-flow units can be sited externally if there is no space in a plant room. Make sure they are fully weather protected and hold IPX5D rating, with frost protection down to -20°C. ■
www.rinnaiuk.com
When measured in economic performance, continuous-flow water heaters cost half the amount to run per year than a combustion unit, based on a peak period of three hours per day at 960 I/h. Typically, a typical water storage-based installation will cost £5,662.13 per year, compared with a Rinnai continuous-flow water hot system cost of £2,736.02.
Product spotlight
Grab a free Vortex in Sentinel’s Filter Fest
Sentinel’s Filter Fest promotion is giving you the chance to claim a free filter for every two you purchase at any merchant nationwide.
You can claim a free Vortex filter directly from Sentinel until June, with an easy claim process and units sent to you directly.
UK commercial director Dan Wilson says: “Sentinel have always tried to support our installers and the gift of a free third filter is our way of giving back today. Filter Fest is a great opportunity for customers to see exactly what the Vortex range of filters has to offer.”
The Vortex range has three filters, each of different size and capacity: from the ultra-compact Vortex250, for use when space is restricted, to the all-purpose yet compact Vortex300, and the larger capacity Vortex500, which is also suitable for systems where heat pumps are installed.
Just complete the claim form at www.sentinelprotects.com/ uk/filterfestclaim and upload your proof of purchase in order to claim the free filter. Terms and conditions apply.
Are you ready to keep heating systems clean?
Fernox is calling on heating engineers to make sure they are implementing the best practice guidance outlined in BS 7593: 2019 before it becomes mandatory. The Code of Practice is due to be introduced into Part L of the Building Regulations next month.
Approved Document L of the Building Regulations is being updated to set out additional measures that will help to keep central heating systems working at optimum efficiency.
The measures include ensuring an in-line system filter is installed, checking inhibitor levels every year and conducting laboratory analysis of the system water, or re-dosing, every five years.
Fernox is encouraging heating engineers to carefully consider the water treatment products that they are using. To make compliance as quick and easy as possible, Fernox says its range of products can help to improve on-site productivity and efficiency at every stage of the commissioning and maintenance process.
Head of chemistry Richard Crisp says: “The Fernox range of water treatment products has been designed to offer engineers an effective, easy-to-use solution for every task.
“For example, our chemical water treatment range comes in 265ml, 500ml and Express 400ml versions to suit a wide range of systems, and all chemicals can be safely used in conjunction with each other for full protection.”
www.fernox.com
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