Using Softened Water in Heating System

autolycus · 3 Nov 2008

Hi,

There seems to be conflicting advice on this forum as to whether or not artificially softened water should be used in a central heating system.

It strikes me that softened water would be best as it avoids the issue of limescale build up within the boiler.

But lots of people on here say that that benefit is outweighed by the fact that the softened water will corrode the radiators faster.

However, the Sentinel website says that as long as you use the right amount if X100 then it is fine to use softened water. See http://www.sentinel-solutions.net/en/heating/X100/questions

So, what's the definitive answer (if there is one)?

If it makes any difference I've got a sealed system and the filling loop is connected to a softened supply. But I can easily bypass the softener whilst filling the system if I want to use hard water.

The boiler is a Potterton Kingfisher that is about 8 years old.

David.

Slugbabydotcom · 3 Nov 2008

In a sealed system once all the chemical reactions of either soft or hard water have taken place you end up with neutralised water. If you have leaks in your sealed system any new water that you introduce will react with your system until it is neutralised.
It takes thousands of litres of too soft or too hard water to cause your system any problems.
Concern yourself more with making sure you attend to leaks quickly. Once you have to top up more than about every 4- 6 weeks its about time to go on leak alert.
Inhibitors are much more effective in open vented systems where the system water is in contact with air. Using an inhibitor additive on a sealed system will give you more protection until you do find the cause of any leaks so I still suggest you use it.

simond · 4 Nov 2008

Manufacturers of boilers with aluminium heat exchangers tend to have a different view.

Take Worcester Bosch, for instance.

autolycus · 4 Nov 2008

Would my Potterton Kingfisher have an aluminium heat exchanger?

Slugbabydotcom · 4 Nov 2008

autolycus said:
Would my Potterton Kingfisher have an aluminium heat exchanger?

No yours is cast iron

autolycus · 6 Nov 2008

So does that mean that, in my case, it does not really matter whether I used softened or "natural" hard water (so long as I add inhibitor)?

David.

gas4you · 6 Nov 2008

Softened water is not very kind to the radiators.

Your water softener should be set to be by-passed when filling a heating system up.

dca860 · 19 Feb 2016

gas4you said:
Softened water is not very kind to the radiators.

Your water softener should be set to be by-passed when filling a heating system up.

dca860 · 19 Feb 2016

You need to quote the source of your information
Where is the proof softened water causes corrosion?
There is evidence that the inhibitor actually causes the corrosion in systems that have softened water as the inhibitor has no calcium to neutralise!
Read this article - which may interest some:
https://www.harveywatersofteners.co.uk/downloads/corrosionreport_dec10.pdf

vulcancontinental · 19 Feb 2016

You've got a Kingfisher on a sealed system with a filling loop? Anyway, Harvey has a product to sell and was caught out years ago misleading people regarding Worcester Bosch recommending softeners in the States and not in the UK. If the boiler is Aluminium don't fill with softened water, stainless steel, cast iron or washed copper I have no experience of it ever causing a problem but ali, no because I have.

FurstyFerret · 19 Feb 2016

Installation guide for my Ideal system boiler specifically forbids the use of softened water.

mogget · 19 Feb 2016

Dca obviously either missed the 8 years old thread warning, or ignored it.

dca860 · 19 Feb 2016

mogget said:
Dca obviously either missed the 8 years old thread warning, or ignored it.

Hi, I am ignoring nothing, however I am asking for proof as there is a massive absence of it.
Harvey does indeed have a product to sell and I don't doubt they will manipulate facts to suit their sales regime (as they did with their claims of soft water curing eczema until Trading Standards dealt with them). That said, I see many pictures of exchangers blocked with debris but I have yet to see any damaged by soft water. Why would some manufacturers of aluminium exchangers support soft water and others forbid it? It either damages it or it doesn't. Is this ignorance or an unwillingness of manufacturers to test their products properly - and failing to spot a growing market? I just don't like re-quoting myth as fact - give me proof!
(Ever heard that the medical profession recommends we should all drink 2 lt water a day? is - another myth)

vulcancontinental · 19 Feb 2016

No proof, only experience. Put an ali boiler in, golly, 20 years ago, maybe more, one of the first condensers. Customer later had a water softener fitted, three months later it's leaking. Boiler manufacturer changed exchanger and tells customer and me don't use softened water, we're getting this all over. I always fitted ali and told the customers not to use softened water, never had another problem, where the customer wanted a softener I used stainless steel or cast iron.

Harvey's say it's fine if the system is inhibited with X100, I say why take a chance, it's fine without a softener. First impressions count and my first impression of Harvey stays with me because it was me who informed him of the misinformation he was giving out, he apologised and continued giving it out. Nuff said.

dca860 · 20 Feb 2016

vulcancontinental said:
No proof, only experience. Put an ali boiler in, golly, 20 years ago, maybe more, one of the first condensers. Customer later had a water softener fitted, three months later it's leaking. Boiler manufacturer changed exchanger and tells customer and me don't use softened water, we're getting this all over. I always fitted ali and told the customers not to use softened water, never had another problem, where the customer wanted a softener I used stainless steel or cast iron.

Harvey's say it's fine if the system is inhibited with X100, I say why take a chance, it's fine without a softener. First impressions count and my first impression of Harvey stays with me because it was me who informed him of the misinformation he was giving out, he apologised and continued giving it out. Nuff said.

Thank-you. Experience is probably the best proof. Lab experiments can rarely replicate home use.
My only observation is that 3 months hardly seems long enough to cause significant corrosion - more likely it has stripped limescale off that had previously been blocking a leak vulnerability?

I also still question why artificially soft water can cause problems. The salt is a catalyst to 're-charge' the resin and it is then rinsed - it doesn't make the running water saline. If it did, you'd taste it (and yes, I do drink soft water from time to time)

diynot

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Using Softened Water in Heating System

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