Immersion elements

[Dodgemonkey]

Hi all,
To put this query in the 'Lectrics forum or not....oh well, you boys know your stuff so here goes...
Is there a specific length of immersion element for a specific cylinder size?
I ask simply because I wondered whether the 27" was the correct one to replace my existing immersion in the 36" x 18" indirect HW cylinder. I'm presuming it is - I don't want too shallow a stratification as would be with anything shorter, but just out of interest is there a general rule about this?
Thanks fellas

 

[Charnwood]

So long as the IH boss is in the domed top of the cylinder, 27" is the one you want.
You can get 36" IHs, but they are for 42" (1050mm) and 48" (1200mm) cylinders.

11" and 14" IHs are for side fitting.

 

[Whitespirit66]

Also, if Middlesex is a hard water area, make sure you pay the extra couple of quid for an element designed for agressive water (Incoloy type).

 

[Dodgemonkey]

Thanks boys - that's brilliant info. Yep, we have seriously hard water here, so the Incoloy type will be a must. Thanks.

 

[Agile]

There is no longer a county or a postal area called Middlesex!

Its still on lists of areas used by web sites though.

I dont see water in the London area as problematically hard as far as boilers are concerned.

The bad areas are Berkshire like Reading and places like that.

Tony

 

[Dodgemonkey]

Dead right Tony, they messed with our county boundaries and we lost the "Middlesex" some years ago, much to local disgust and outrage. Most postal stuff however is still marked Middlesex, for which I'm happy.
On the water hardness front, we might not be at the zenith of ultra hard water supplies, but we do draw the bulk of our potable water supplies mainly from deep well sources in the Thames valley, and as a result calcium and magnesium take up is moderately high, so I'd swerve towards the Incoloy type of immersion element for peace of mind. Not that it's something I lay awake thinking about