The damaging effects that limescale can have on the lifespan of a boiler and the energy efficiency of a central heating system are significant. Part L of the Building Regulations stipulates that where mains hard water exceeds 200 ppm, feed water to water heaters and the hot water circuit of combination boilers must have a scale reducing device fitted. Why is descaling important Limescale prevention An effective method of treating water to avoid the build-up of limescale is to install an in-line Fernox Scale Reducer. An Electrolytic Scale Reducer will provide whole house protection, while a Magnetic Scale Reducer is suitable for single appliances. Both products can be easily connected directly onto 15 mm or 22mm horizontal or vertical pipe work using compression fittings or 15mm horizontal or vertical pipework using 15mm pushfit fittings. Limescale removal Where limescale has already formed it can be removed from a hot water system, including the storage cylinder, immersion heater, pipework and taps using Fernox DS-3 Cleaner. After turning off the boiler and/or immersion heater, tie-up the ball valve or isolate the mains water supply to the cold water storage tank. Then open all hot water taps before draining the entire system, and close the taps again afterwards. Having dissolved the Fernox DS-3 in warm water at the maximum concentration of 1kg per 10 litres of water, introduce the solution into the cold water storage tank either via a funnel connected to rubber or plastic tubing or directly, if the cold water storage tank serves the hot water cylinder only. Refill the system until the water level in the cold water storage tank just covers the cylinder feed connection. After this is done, turn on the boiler and/or immersion heater and heat the acid solution in the hot water cylinder to 50-60°C. Maintain this temperature for at least four hours, opening all hot water taps briefly every 10-15 minutes to allow a half to one pint (284 to 568ml) of acid solution to run into a plastic container. Finally, turn off the boiler and immersion heater, and drain the hot water system completely, bailing out any residual water from the cold water storage tank. Release the ball valve of the cold water storage tank and thoroughly rinse the entire hot water supply system, opening all hot water taps. Where applicable the cold water system should also be rinsed, as some acid may have entered via the cold water storage tank. Any waste solutions of DS-3 Cleaner should be neutralised with Fernox System Neutraliser before discharging to the drain.

Minerals in chalk or limestone rock collect as water permeates through the ground and collects in aquifers. These minerals remain within the water and are carried into the domestic water supply. What causes limescale deposition? They inevitably reach central heating and water systems, where they build-up over time to cause blockages in pipework, efficiency losses and the premature failure of components. These problems can arise in both the primary water system (the central heating system) and secondary (household hot water) system. The mineral deposits, collectively known as limescale, consist primarily of calcium and magnesium carbonates which are generally insoluble. Limescale occurs when these deposits are formed as a result of heating water that contains soluble bicarbonate salts (which are thermally unstable and break down to form carbonates). There are several factors that contribute to the build-up of limescale, including:

• High (temporary) hardness
• Elevated pH (alkalinity) of the water
• Elevated temperature

What should be done? Prevention is always better than cure. In central heating systems, the addition of any Fernox Protector F1 will prevent deposition of limescale. For domestic hot water systems, Fernox offers a range of scale reducers designed to provide either whole house or single appliance protection. For whole house protection, the Fernox Electrolytic Scale Reducer should be installed on to the mains water supply to the property. To protect single appliances such as the boiler, the Fernox Magnetic Scale Reducer is ideal. If the central heating system is already contaminated with limescale it should be cleaned using an acid-based cleaner such as Fernox DS40 Descaler & Cleaner. However, descaling alone will not restore the central heating system to its original condition. After descaling it is imperative to protect the system against further scaling by adding any Fernox Protector F1 or if a system filter is fitted Fernox Protector + Filter Fluid If limescale formation has occurred within the hot water system, individual appliances such as kettles, showerheads and heat exchangers can be descaled using Fernox DS-3 Limescale Remover. For open vented systems Fernox Superconcentrate Limescale Preventer is an ideal way to keep system water scale-free.