Hard Water Solutions: Essential DHW System Maintenance Tips

Hello, Champions of Net Zero!

Today, we delve into an often-overlooked aspect of domestic hot water (DHW) systems—hard water. In our quest for net-zero solutions, understanding the implications of hard water can significantly enhance the efficiency and longevity of our systems. Pete Seddon, Head of Technical at Rinnai UK, sheds light on the intricacies of hard and soft water, the long-term effects hard water can have on DHW systems, and the best practices for maintenance and prevention.

Hard water is defined as water that contains a high concentration of dissolved minerals, primarily magnesium and calcium. This phenomenon occurs when rainwater flows over certain geological formations, such as chalk and limestone, picking up these minerals along the way. As the water infiltrates the UK’s water supply, it retains these minerals, which are harmless to human health but can wreak havoc on our plumbing systems.

The regions most affected by hard water in the UK are predominantly in the south and south-east, including areas like the Thames Valley corridor, the Cotswolds, London, and parts of the Home Counties such as Kent, Sussex, and Surrey. These areas boast substantial chalk and limestone deposits, leading to higher levels of hardness in the water. Fortunately, most water companies provide postcode checkers on their websites, allowing residents to ascertain the hardness of their water supply.

The impact of hard water on DHW systems is profound and can lead to significant long-term consequences. One of the most notable effects is the accumulation of limescale within the system. When limescale forms, it adheres to the internal components of a DHW unit, severely compromising its performance and efficiency. As limescale builds up, it acts as an insulator, hindering the transfer of heat to the water. Consequently, the system must work harder and for extended periods to achieve the desired water temperature, leading to increased energy costs and accelerated wear and tear on components.

Moreover, the presence of limescale can cause corrosion and erosion in the internal metal components of boilers, storage water heaters, or continuous flow water heaters. This can result in leaks, heightened maintenance costs, structural damage, and ultimately, an early demise of the product lifecycle. Therefore, addressing the challenges posed by hard water and limescale is essential for maintaining the integrity of DHW systems.

Fortunately, several solutions are available to combat the adverse effects of hard water. Water softeners are one effective option for preventing limescale formation. These devices work through a process known as ion exchange, replacing calcium and magnesium ions with sodium and potassium ions to soften the water. While water softeners are highly effective, they can also remove existing limescale build-up, although this process may take time. It is essential to conduct thorough research to determine the most suitable treatment for your system.

Another innovative solution is the use of limescale converters, such as Aquabion. These devices are installed in the plumbing and begin treating hard water as it flows through. By altering the structure of lime particles in the water, they reduce the likelihood of limescale adhering to surfaces. Unlike traditional salt softeners, limescale converters maintain the mineral content of the water while introducing beneficial elements like zinc, which can provide health advantages.

Magnetic and electronic water conditioners offer additional non-chemical solutions for limescale removal. These devices utilise magnetic and electronic fields to disrupt the behaviours of calcium and magnesium minerals, making it less likely for limescale to form and adhere to the internal components of hot water systems.

If limescale has already established itself within a system, a simple yet effective solution involves the use of light acidic substances, such as white vinegar. The acidic properties of vinegar are ideal for breaking down hard water accumulations. Various chemical descaling solutions are also available, including hydrochloric, phosphoric, sulfamic, lactic, and oxalic acid compounds, all of which can effectively eliminate limescale. However, it is crucial to select a suitable descaling solution tailored to your specific needs, as these products are often more effective and quicker in addressing existing build-up.

At Rinnai, our mission is to empower customers with the knowledge necessary to optimise their hot water and heating systems throughout their lifecycle. We are committed to sharing insights that help installers, specifiers, contractors, and end-users make informed choices based on practical, economic, and technical criteria. Through our dedication to education and information dissemination, we strive to enhance the performance and resilience of DHW systems in the face of challenges posed by hard water.

As we navigate the path toward a net-zero future, Rinnai is proud to offer a diverse range of products designed to lower carbon emissions while simultaneously reducing customer costs for commercial, domestic, and off-grid heating and hot water delivery.

Our H1/H2/H3 range includes an array of hot water heating units powered by gas, BioLPG, DME, and hydrogen-ready technologies. Additionally, we provide electric instantaneous hot water heaters, electric storage cylinders, buffer vessels, and a comprehensive selection of heat pumps, solar solutions, and hybrid configurations. This extensive product range allows contractors, consultants, and end-users to choose efficient, robust, and affordable low-carbon options tailored to their specific requirements.

Rinnai is a world-leading manufacturer of hot water heaters, producing over two million units annually across five continents. Our reputation is built on delivering high-performance, cost-effective products that boast extended lifespans. With all Rinnai products UKCA certified and A-rated for water efficiency, customers can access a variety of fuel options. Our commitment to customer service ensures that any unit can be delivered to any UK location within 24 hours, 365 days a year.

Furthermore, Rinnai offers carbon and cost comparison services that enable customers to calculate the financial and environmental savings associated with investing in our systems. We also provide a comprehensive system design service to recommend the most appropriate solution for each property.

In addition to our extensive product offerings, Rinnai is committed to providing comprehensive training courses and technical support in all aspects of the water heating industry, including detailed continuing professional development (CPD) sessions.

Our product range encompasses all available fuels and appliances, including electric, gas, hydrogen, BioLPG, DME, solar thermal, low global warming potential (GWP) heat pumps, and electric water heaters. To learn more about our full product availability and to explore our “Help Me Choose” webpage, please visit our website.

In conclusion, understanding the implications of hard water on DHW systems is crucial for optimising performance and extending the lifespan of appliances. By employing effective solutions and preventive measures, we can mitigate the impacts of hard water and enhance the sustainability of our heating and hot water systems. Together, we can champion the cause of net-zero and create a more efficient, environmentally friendly future for all.

For more information, visit www.rinnai-uk.co.uk or email engineer@rinaiuk.com.