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Preventing Limescale

What causes limescale deposition?

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. They inevitably reach central heating and water systems, where they build up over time and 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 are deposited by 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, Fry Electrolytic Scale Reducer should be installed on to the mains water supply to the property. To protect single appliances, such as the boiler, Fry 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 DS-40 System 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.

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.