In-line scale inhibitor

[ln1234]

Are there any recommendations for an in-line scale inhibitor we can put on the incoming domestic main for the whole house? Water is reasonably hard in our area, and we'd like to put a whole house solution in place for this if possible.

Ideally something that enables safe drinking water and doesn't reduce the flowrate too much.

Cheers

 

[45yearsagasman]

I have used an HS38 hydroflo for the last 2 years and have found it has worked for me.Just needs a 240v supply and does no affect drinking water.Easy DIY install.Wait for all the responses as each will have a different take on this.

 

[Boilerman2]

No substitute for a Water Softener - the only way to soften water!

 

[mickyg]

Depends how hard your water is. Where I live is ridiculous and the only thing that works is a proper softener. The effect of other devices is limited, but again I think it depends area to area. I often fit inline magnetic devices just to satsify boiler manufacturers but I don't have any faith in them doing a great deal.

 

[ianniann]

You wouldn't normally use softened water for drinking and cooking. Not that's poisonous exactly but the chemicals in it (eg. sodium) are not healthy to take too much of. For drinking, you keep a "pure" feed and filter it if you want to.

Do you want to soften the water for the entire house, including things like washing and bathing, or just inhibit scale for the boiler?

 

[gasgas]

I had a long talk with a water softener manufacturer recently.

How do they work? The hard water passes through a tank full of resin beads which attract the calcium in the water and it sticks to the beads. Once in a while according to your water hardness the softener back-flushes the resin beads with a salt solution which dissolves the calcium off the beads and sends it down the drain. The beads do not dissolve and last for ever. You refill the tank with salt when the level gets low.

Can you drink softened water? A glass of softened water contains about the same amount of salt as two slices of white bread. i.e negligible, but measurable if you have access to The National Physics Laboatory. You don't get the health benefits of calcium if you drink it all the time.

What effects does hard water have on boiler innards? Calcium reacts with Aluminium (in heat exchangers) and produces aluminium oxide. This is the stuff they make sand paper with. When you clean out the condensate syphon of an aluminium boiler (eg some Worcesters) if you rub the grey grit between your fingers it will scratch your skin. The heat exchanger is slowly dissolving as a result of hard water reacting with aluminium.

How hard is my water? Go to the web site of your water supplier and enter your post code. They will give you the hardness in degrees Clark.

How does a 'magnetic' in line scale inhibitor work? I havent a clue. When did you last encounter magnetic chalk?

 

[twgas]

What effects does hard water have on boiler innards? Calcium reacts with Aluminium (in heat exchangers) and produces aluminium oxide. This is the stuff they make sand paper with. When you clean out the condensate syphon of an aluminium boiler (eg some Worcesters) if you rub the grey grit between your fingers it will scratch your skin. The heat exchanger is slowly dissolving as a result of hard water reacting with aluminium.

This statement implies that hard water inside a heat exchanger reacts with the outside surface of the same h/ex. Did you get this statement from a sales leaflet or technical.

 

[gasgas]

Yes I must admit I had wondered about that. The oxide in the condense trap must come from the water content of the gas. You don't get it from stainless steel heat exchangers do you.

 

[twgas]

I agree that the Ali oxide will be caused by the gas (condensate). Was it a salesman you spoke to?

 

[ianniann]

Calcium reacts with Aluminium (in heat exchangers) and produces aluminium oxide

Good one! Rubbish of course. Both aluminium and stainless steel slowly react with all manner of impurities in water, perhaps the most important being dissolved oxygen, but calcium isn't the culprit. Aluminium oxide isn't a serious form of corrosion because it forms a thin solid layer that doesn't flake away like iron rust. Aluminium corrosion comes with things like Aluminium chloride which is a flaky white solid. Heat exchanger corrosion in general is a problem with very soft water because of its low pH. In fact some (all?) boiler manufacturers instruct you not to run softened water (as described above with the salt and the beads) through your boiler.

The main problem with hard water is scale. This is the deposition of solid calcium carbonate (limestone) on the inside of your pipes and your boiler. Scale is formed rapidly when hard water gets very hot. There are scale inhibitor devices specifically designed for use with boilers. Some of them are chemical like the water softeners although they use a different chemical. Then there are those magnetic gadgets, I have no idea how effective they are. One boiler manual recommends that water above pH8 or above 200ppm hardness should be treated in some way before you put it through your boiler although it didn't suggest any particular treatment.

 

[ianniann]

Can you drink softened water? A glass of softened water contains about the same amount of salt as two slices of white bread. i.e negligible, but measurable if you have access to The National Physics Laboatory. You don't get the health benefits of calcium if you drink it all the time.

A water softener manufacturer told you this? It must be true then

As I said, softened water is not toxic, but it isn't good for you. When essentially everyone in the country already consumes far more sodium than is good for them, adding more is not a good idea. Ask your doctor next time and see if you get the same answer. The doctor would probably also like you to consume the minerals in the hard water, although personally I don't like the taste.

 

[twgas]

Without getting into the science behind it, you (ianniann) said

Aluminium oxide isn't a serious form of corrosion because it forms a thin solid layer that doesn't flake away like iron rust

If that is the case, how does it get into the condensate trap?

 

[ianniann]

how does it get into the condensate trap?

Not from calcium in the hard water, that's for sure. I'll do a bit of research into aluminium corrosion and see what I come up with. Acidic condensate is sounding like a good culprit to me.

Aluminium oxide is what prevents its corrosion in normal circumstances. Aluminium is actually a very reactive metal, but the oxide forms naturally and is unreactive. Most aluminium corrosion in normal conditions is caused by salt or by galvanic reactions. The oxide is not stable below about pH4 so possibly acidic condensate would cause corrosion. The oxide is also unstable above pH9, but that won't occur even in the hardest water.

Stainless steel is "stainless" by a similar mechanism, with chromium in the alloy creating an unreactive oxide layer on the surface. Again, chlorine from salt is the most common way that stainless steel corrodes. Galvanic corrosion is also possible but presumably shouldn't an issue in a properly designed boiler.

 

[ChrisR]

If you have a water softener, the regs somewhere I can't quote, say you must have a non-softened tap, traditionally the kitchen sink.

Any aluminium surface exposed to atmosphere will oxidise pretty quickly. All the stuff in the condense trap is oxidised. Not quite the same as big Al ox crystals used for abrasives though. Anodised Al is oxidised, not exactly sharp though is it.
The oxide IS protective, though the layer is thin. A strong alkali will disrupt it, such as sodium hydroxide. Weak acids such as in condensate, will repair the protective coating.

The Worcester casting are pretty rough - check a new one sometime. In the first year or so you do get a tablespoon of Al out of them which blocks the condense trap nicely. After that, hardly anything comes out of them, so I don't think it's a serious problem.

Ally hexs have been around for a number of years now, and there simply aren't screams of woe from people where they've "dissolved".
It may be going on to some extent, plumbers tend to chuck out failed parts rather than analyse them, so we don't know a lot about whether hex failures are due to corrosion or some other problem.

I've been watching and listening about "water conditioning" over the years. There's some good science saying how some of them can work a bit some of the time, but after that it all gets flaky. Some of the anecdotal evidence is compelling, but guys eg in water heating business like Andrews, who want the answers but don't actually make the conditioning products, find they can't repeat the results reliably. Sometimes they do nothing at all. I have to conclude that there's more, that we don't know yet.

What I find revolting is that some of the people who make the things have not the slightest clue what they're talking about. I collared the boss of Hydroflow one at a plumbing exhibition. I asked questions, and more questions, and he went off into orbit in a fantasy world about electric waves and chains of water molecules - for which there's no evidence. When he found out I have degrees in metallurgy & materials, and also electronics, he said it was only theories. AH . The annoying thing is that the Hydoflow devices DO seem to work well SOME of the time!

 

[enb54]

I believe "gasgas" hit the nail on the head with "How does a 'magnetic' in line scale inhibitor work? I havent a clue. When did you last encounter magnetic chalk?" .

Anyone wanting to verify this can scrape some (as much as you want) of the buildup out of their water line and mix it in a glass beaker of water, place any magnetic or electric field (of any frequency you wish to generate) close by and see if the calcium carbonate dissolves, is attracted, or in any way is affected by said magnetic or electric fields. Even after weeks of exposure, I think you'll get the same results I did, exactly no change in the solution. However, if you use a bit of common sense to remove scale chemically, for instance adding several tablespoons of vinegar to your electric kettle water and letting it sit for several hours, you'll be guaranteed reproducible results. That is what's called 'scientific method' and in real science, it's all about 'reproducible results.'

As several posters have alluded, anything that is not consistently reproducible is not related to our physical world, and therefore should be treated with extreme skepticism. A quick read of the Wikipedia entry at http://en.wikipedia.org/wiki/Calcium_carbonate (it's not necessary for you to plod through the chemical formulas) should be enough to convince 90% that no electromagnetic field is going to affect scale buildup. I should also mention that metal pipe is a very effective conductor of electrical energy and effectively blocks or shunts external electromagnetic fields, so any consumer device that claims to penetrate this pipe and affect the non magnetic contents could have very interesting military applications...

In summary, common sense ways to remove scale would be chemically or mechanically (includes ultrsonic vibration!), but chemically is the easiest, using any of the well known commercial scale dissolving mixtures (including vinegar). Thorough rinsing after chemical cleaning is of course understood. Anyone who believes that electromagnetic fields affect scale buildup is welcome to reproduce the 'beaker' experiment described previously (no magnetic metal particles allowed, just water pipe scale!).

Anyway, I have assisted (reproducibly) several friends who were experiencing scale buildup problems (which took years to manifest themselves), and upon discovering this forum, just had to send off my take on this subject. Always remember that old adage "A fool and his money are soon parted" or something like that...