So the gas fitter came to call....
and expressed concern about using an ion exchange (salt) water softener with a thermal store. Corrosion of heat extract coil due to salt content in treated mains supply.
Google hasn't found much apart from now discounted worries about boiler heat exchangers.
Gledhill technical advice dept. were only accepting voice messages (poets day?)
Anyone come across this. In 25 years it has failed to penetrate either the side walls or the coil in our hot tank.
purely on the basis of gut feel that if the level of salt in the water cannot be tasted then I cant really credit that corrosion can be a risk.
Never had a water softener and hated showering in places where they have been fitted so no practical experience to offer. Can you get thermal stores with stainless steel heat exchangers. Might open up a whole load of electrolytic problems? Mine is all copper and I don't recall being offered a choice of materials when I had it custom made.
I rather wonder if this is a plumber remembering some hue and cry about aluminium heat exchangers. Viessmann actually encourage the use of softened water for the initial pressurised circuit fill. (Stainless)
I live with a cleanliness fetishist!
I'd be more worried about the human who might consume it not the boiler. Salt sugar etc, I do sometimes wonder if there is anything in the world that does not do harm to something or somebody eventually. I'd have thought the lime scale was far more of a problem than the salt, myself.
Brian
In message , Brian Gaff writes
:-) I'll get technical advice from the manufacturers on Monday.
There might be a hint in the handbook which points to a requirement for anti scale treatment for mains water exceeding 200ppm. Ours is 205! It goes on to suggest using a polyphosphate in line system which they can supply.
No mention of not using a conventional salt system.
Seems unlikely to be a problem in the shot to medium term - and probably not one long term I would guess. (the treated water will have a higher sodium content, but it would be salty since the saline is flushed down the drain)
Which should give you some confidence here...
Untastable levels of chloride can be sufficient to cause stress corrosion cracking in certain stainless steel welds (but IIRC only above about 50 deg C).
I believe the thermal store coils are finned copper. The planned boiler has stainless steel inox radial heat exchanger and the manufacturer encourages using softened water in the closed circuit system.
I'll see what Gledhill technical have to say tomorrow and report back:-)
In message , Tim Lamb writes
Gledhill technical seemed happy for an ion exchange softener to be used for DHW. They pushed their polyphosphate offering but did not reject the alternative.
I have since asked a similar question of my softener supplier who was confident this is a red herring.
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