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The "NoCalc" limescale inhibitor

My letter to Mr David Cole at NoCalc asking for clarification of claims made by his company for their product:



Dear Mr Cole

As a professional plumbing and heating engineer working in an area of hard water (the local water supplier quotes 277ppm) I am naturally concerned with preventing or mitigating the effects of limescale on my clients' appliances and installations.

Your NoCalc product has just been brought to my attention. Your brochure at http://www.nocalc.eu/Downloads/NC_Brochure_Engels.pdf says that your product is a polyphosphate-dosing type of scale inhibitor. Thus it seems to be similar to systems such as the Culligan whole house scale-reduction system: http://www.screwfix.com/prods/20315/, the Cistermiser "Combi-Mate" http://www.cistermiser.co.uk/products/combi.aspx, and other products from Fernox and others.

I am concerned about the claims you make for your device.

Water Softening
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You repeatedly claim that water treated with your NoCalc system becomes softer and that, for example, this will result in a reduction of limescale deposits "on sanitary fittings, tiles, shower walls and other surfaces". I am not a chemist and do not claim expertise in this field but as I understand it phosphor-dosing systems inhibit limescale from precipitating out when water is heated but do not remove the calcium salts from the water or change them into equivalent sodium salts as water softeners do, so when treated water evaporates the calcium salts are still left behind as deposits on taps, shower heads, tiles etc.

Cistermiser's Combi-Mate FAQ at http://www.cistermiser.co.uk/faq/combi_faq.aspx seems to confirm my understanding. It says:

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I have a Combimate fitted but still have scale in my showerhead / kettle / taps.

Combimate is not a water softener. Combiphos greatly reduces scale deposits and over months and years will slowly reduce scale which has been deposited before the installation of the Combimate. Combiphos reduces the amount of scale deposits by keeping the minerals which cause scale in a dissolved and suspended state at higher temperatures. As a result most scale-causing minerals pass through the system instead of forming scale deposits on heating elements in boilers, kettles and other appliances. Unlike softened water, water which has passed through a Combimate remains unchanged so hard water treated with Combiphos but left in a kettle or at the end of a shower head may still create a build-up of scale when the water evaporates. Users should therefore empty the kettle after use every time it is boiled to prevent scale build-up or wipe the element (when the unit is unplugged) at least once a month after use. Shower heads may also need to be wiped every few months to remove surface scale residue.
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Health
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In "The effects of soft water on the human body" your brochure says "In a recent study at the University of Portsmouth, professor Taraneh Dean conclusively found that there is a link between hard water and skin irritation and eczema". I know this subject is important to at least one of my clients and I would like to know more. I presume you are referring to Portsmouth University School of Health Sciences and Social Work Research's current research project "Water Softeners for Atopic Eczema: Randomised controlled trial of ion-exchange water softeners for the treatment of atopic eczema in children (Tara Dean)" (http://www.port.ac.uk/research/shsswresearch/projects/). I cannot find any publication of results from this research - please can you give me a reference? And please can you explain how this research, which seems to involve ion-exchange water softeners, applies to phosphor-dosing scale reduction systems?

Energy Consumption
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Your brochure, under the heading "NoCalc and saving energy costs" says "Heating up water in your household accounts for about 60 to 70% of the total power consumption." Could you clarify this figure please? Do you mean heating Domestic Hot Water as supplied through hot water taps and showers, or do you mean heating the primary water in a hydronic central heating system to provide space heating?

The brochure goes on to say: "However, limescale has an adverse effect in main pipes and heating systems. You only need a very small amount of limescale deposit to cause a less effective heating system."

Again could you clarify this please? For example in a typical domestic central heating system using 22mm and 15mm pipework I think it would require a huge amount of limescale deposit to significantly constrict pipework and reduce the effectiveness of the heating system. And since the primary water in a heating system is not subject to continual renewal the amount of limescale deposited in the system is minute.

The brochure gives a table:
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Limescale deposit (mm) 0,4 0,8  1,6   3,2   4,8   6,4  9,6 12,7  16  19
Waste of energy        4%   7%   11%  18%   27%   38%  48%  60%  74% 90%
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What does the thickness of limescale deposit refer to - where is it measured? And how is the "Waste of energy" measured?

You say "By installing the NoCalc system, you can save energy by keeping water free of calcium. If you have soft water, you may achieve a 20% reduction on your energy bills. A family of 4 uses an average of 2000 m3 of gas or the equivalent in electricity to heat up each year. A NoCalc system pays for itself within one year and will save you hundreds of Pounds."

Please explain how the NoCalc system keeps water free of calcium (rather than simply inhibiting deposition of temporary hardness slats when water is heated) and how you arrive at the figure of 20% reduction of energy bills when using soft water.

Under the heading "Adverse affects of limescale" your brochure lists "Higher electricity bills". Can you explain this please? The only significant uses of electricity in a hot water and central heating system that I can think of are if electricity is used for heating water or for space heating. In the case of space heating via convection or storage heaters there is no use of water so your device is irrelevant, so I assume you mean heating water via an electric immersion heater. In this case I would expect limescale deposits on an immersion heater to reduce the ability of the heating element to transfer heat to the water causing the element to run hotter and reducing its lifetime resulting in more frequent failure and the expense of replacement. However practically all the power generated by the element will still end up in the water so its efficiency will be practically unaffected. For limescale to result in higher electricity bills a significant amount of the energy would have to end up elsewhere, which I can see no mechanism for.

Filter
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You also claim that your filter product will extend the life of central heating systems and boilers. Please explain this.

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