Stainless steel hot water cylinders

Hedgecutter

Hi all.

I need to replace my hot water cylinder. Its a solar copper cylinder.

I cant source a solar copper cylinder and will have to go with a stainless steel one. One of the suppliers mentioned that if im in an area with lime and use a water softener i should think about buying a marine grade stainless steel cylinder as apposed to a 316 grade cylinder. We have lime in our water but its doesn't cause trouble.

He said the 316 grade will start to break down in two to three years. Has anyone experienced this. Thought 316 stainless would have been more robust.

Dr.Tom

https://www.boards.ie/discussion/2058331783/stainless-steel-hot-water-cylinders

I work with all different grades of stainless steel daily. Id like to hear what the supplier refers to as "marine grade" stainless steel.

We have various products going through our 316 SS manufactured parts that the hobs of hell wouldn't shift so Id say a 316 SS cylinder will be just fine.

Calahonda52

https://www.boards.ie/discussion/2058331783/stainless-steel-hot-water-cylinders

I think they are mixing it up: the base level, IIRC, is 303 or 304 and 316 is next

trouble if they are making both how to they ensure you are not being stuff with 304 for 316 prices

For waht its worth the 316 is really only marine splash proof, not full contact 24/7

Hedgecutter

This is the brand of cylinder he recommended.

https://aquatech.ie/cylinders-2/

h

Dr.Tom

That's a 1.4521 grade stainless which is very similar to 1.4404 which is 316 stainless.

What they seem to show in their comparison table is a comparison to 304 stainless (1.4301) which is maybe why he us recommending it.

Hedgecutter

So do you think he got his grades mixed up and it a 304 grade Vs a 316 grade?

Dr.Tom

https://www.boards.ie/discussion/comment/121628569#Comment_121628569

I cant say that for sure. The tank you linked doesn't have a 316 option.

I have a Joule cylinder myself which is a duplex stainless steel (1.4462) and has better wear and corrosion resistance than 316 (1.4404).

I cant see there being any issues with 304

gw80

https://www.boards.ie/discussion/comment/121628688#Comment_121628688

I would say that is what the guy meant by marine stainless,as duplex is used for a lot of marine applications, ie:offshore rigs and the likes,

Mellor

https://www.boards.ie/discussion/comment/121628569#Comment_121628569

Yeah, sounds like he got mixed up.

304 is basic (most common) stainless. Marine grade is a marketing terms, but 316 or 316L is most often used for those applications.

The product above is 444 grade. Which is very similar to 316 and has similar pitting resistance. I wouldn't pay a premium vrs 316. Don't go 304 obviously

Hedgecutter

https://www.boards.ie/discussion/comment/121628748#Comment_121628748

1,700e for the 316e and 900 for the 304. 😥

Dr.Tom

My Joule 300L Solar twin was €960 last month from my local plumbing supplier.

Hedgecutter

https://www.boards.ie/discussion/comment/121629472#Comment_121629472

That's something I forgot. The 900e quote he gave me was for joule. What grade is the joule?

Dr.Tom

https://www.boards.ie/discussion/comment/121629547#Comment_121629547

As per my earlier post, the material is Duplex.

https://www.joule.ie/products/cyclone-twin-solar-ie/

Hedgecutter

https://www.boards.ie/discussion/comment/121629629#Comment_121629629

Look like the job. Is that a vented tank?

Calahonda52

https://www.boards.ie/discussion/comment/121629653#Comment_121629653

How well did you look?

Hedgecutter

https://www.boards.ie/discussion/comment/121630025#Comment_121630025

I meant the one Dr Tom bought

Dr.Tom

Mine was open vent