The storage cylinder I have is unvented, and I believe it to be of steel construction.
There is no external cladding on it to retain heat, is this normal, as I imagined it would be the same as a conventional immersion tank.
I would welcome you comment
A Platt

A Platt, November 2009

Thanks for your comment.
The only information I have about the cylinder is in the instruction manual I have now got hold of - Potterton Performer - Model 125-200.
It does show a shaded internal casing, perhaps indicating some sort of thermal barrier, why don't the manufacturers show this type of info more clearly.
Thanks again.
A P

A Platt, November 2009

You don't mention the make - I was looking at a brochure for some of these only yesterday - Stainless Steel super duper jobs - Range Tribune. The brochure shows a relatively narrow inner cylinder of Stainless Steel covered with an insulation coating and a painted mild steel outer cover. I'm pretty sure you have insulation on yours... A manufacturer would not get many sales of uninsulated cylinders in the current energy saving climate.

http://www.plumbnation.co.uk/site/range-tribune-solar-twin-coil-indirect-unvented-hot-water-cylinders-/large-tribune.jpg

Peccavi, November 2009