Shouldnt this tank have insulation on it?

[TomBowyer]

Hi,
I think this is my hot water tank (immersion heater?). If so, shouldnt it have some insulation wrapped around it, or does it have some clever form of internal insulation?

Or... is it actually a cold water tank?

Image:
http://www.jez.im/public/immersion.jpg

Thanks!
Tom.

[plumbbob]

The tank is already covered in a high efficiency foam insulation which is the blue surface you see. The top half is the cold water and the lower tank is the hot water cylinder.

[TomBowyer]

Ahh, right thanks, from a distance the blue/green/grey stuff looked solid like it was the shell of the tank.

Why does the tank have cold water at the top, does that supply the bathroom/outside taps or something?

[plumbbob]

No, it does not supply taps directly. It just a "combination cylinder" that combines both a header and separate hot water cylinder into one unit.