Wall Mounted Autofill

Wall mounted autofill boiling water units require mains cold water and electrical connections. They are generally mounted directly over a sink so that water from minor spillages will flow through the existing sink waste.  Installation is normally quite straightforward.

Electrical Connection (A) These units usually use electric heating elements rated at 3kW or less and may be wired to a domestic ring main, normally via a switched fused spur. The electrical power requirements are similar to a typical electric kettle. There is normally no need to run a separate heavy duty cable to the electrical consumer unit.

Water Connection (B) The water supply connection is made by tee-ing from the cold water mains. It is recommended that a service valve is also fitted at the time of installation to faciliitate future maintenance or re-siting of the unit.

Vent (C) All units have a vent which to allow hot water and/or steam to be safely discharged.

Scale formation is due to the presence of naturally occurring calcium and magnesium salts (bicarbonates, carbonates and sulphates). These salts are readily soluble in cold water, but as hard water is heated to boiling point the dissolved carbon dioxide is driven off, which reverts the bicarbonate salt to the insoluble carbonate state which then precipitates out of solution on cooling. This is the origin of the scaling, which occurs on all water boiling products in hard water areas where the concentration of these salts is highest. It is most commonly seen as a light grey 'fur' on kettles. All water boiling products are susceptible to scaling in hard water areas, with scale formation being greatest for products that are in constant use. Scale often precipitates on the heater element. As the layer of scale is a relatively poor conductor of heat compared with the metallic element, the effectiveness of the heat transfer from heater element to water is reduced and it takes longer to heat water to boiliing point. Unless treated scale can ultimately result in the heater element failing through over heating, in much the same way as a domestic kettle if allowed to boil dry. Fortunately, a simple and inexpensive remedy for scaling exists in the form of household scale removal products available from virtually all high street supermakets. Other options include the use of scale inhibitor products, although these are generally more expensive. It should be noted that manufacturers warranty may be invalidated if a product fails due to untreated scale formation.

Please note that wall mounted boiling water units must be installed and operated in accordance with the manufacturer's specific requirements and by competent personnel.

The phenomenon of scale (limescale) is due to the presence of naturally occurring calcium and magnesium salts (bicarbonates, carbonates and sulphates).  These salts are readily soluble in cold water, but as hard water is heated to boiling point the dissolved carbon dioxide is driven off, which reverts the bicarbonate salt to the insoluble carbonate state which then precipitates out of solution on cooling. This is the origin of the scaling, which occurs on all water boiling products in hard water areas where the concentration of these salts is highest. It is most commonly seen as a light grey 'fur' on kettles. All water boiling products are susceptible to scaling in hard water areas, with scale formation being greatest for products that are in constant use. The following map shows the areas in the UK with hard water.

The scale often precipitates on the heater element. As the layer of scale is a relatively poor conductor of heat compared with the metallic element, the effectiveness of the heat transfer from heater element to water is reduced and it takes longer to heat water to boiling point. Unless treated, scale can ultimately result in the heater element failing through over heating in much the same way as a domestic kettle that is allowed to boil dry.

Fortunately, a simple and inexpensive remedy for scaling exists in the form of household scale removal products available from virtually all high street supermarkets. in hard water areas autofill boiler water units are often used with in-line limescale inhibiting filters which typically provide protection against the effects of limescale for 6 months or so without requiring additional maintenance.

It should be noted that manufacturers' warranties may be invalidated if a product fails as a result of untreated limescale formation.