The Accidental Smallholder Forum
Smallholding => Renewables => Topic started by: mclintan on May 18, 2021, 02:11:47 pm
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On a private water supply in the Scottish Highlands.
Gravity-fed, spring source - soft, somewhat acidic (pH 6.3 when last tested).
Looking to replace our (27ish year old, Grade 2) existing copper cylinder with a suitable stainless steel replacement.
System is open-vented, indirect. 28mm coil, 28mm / 1"BSP fittings for cold feed/hot water draw-off.
Any pointers? And if our copper cylinder has lasted 27(ish) years, are we likely to have any corrosion issues with a stainless steel cylinder? 316L vs Duplex vs Super Duplex?
Wanting to move away from copper because the cylinder/pipework is clearly corroding (tell-tale blue/green staining of sanitaryware, etc), amid other reasons.
Many thanks to all!
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Any pointers? And if our copper cylinder has lasted 27(ish) years, are we likely to have any corrosion issues with a stainless steel cylinder? 316L vs Duplex vs Super Duplex?
Now would be a good time to allow for a solar hot water panel if you either fancy doing it or think that might be in your future.
I'd expect 316L to be more than adequate for tap water. At domestic hot water temperatures, you have to worry a bit about "stress corrosion cracking", but IIRC that's only in the presence of chlorides. Is any chlorine used in your system?
Also, wouldn't duplex be horrifically expensive? I'll admit I've only ever bought one duplex SS tank before. It was 70,000 litres capacity, so a bit bigger than yours ;) . However, I recall nearly dying at the price! :o