art L of the Building Regulations (conservation of fuel and energy for dwellings) states that where the mains total water hardness exceeds 200ppm, provision should be made to treat feed water to water heaters and hot water circuits of combination boilers to reduce the rate of accumulation of timescale and to limit its harmful effect on energy efficiency.
Electrolytic scale inhibitors are listed in the Domestic Building Services Compliance Guide as a suitable control. As water flows through the unit it emits charged zinc ions which induce hardness salts to cluster together and pass through heating appliances rather than forming Iimescale deposits on the heat exchanger or water heating element. Service life is dependent upon local water conditions and water usage. When the beneficial effect subsides its time to replace the unit.