cylinder type?

[finks]

hi all
i am renovating a ground floor flat ,which has the hw cylinder in the bathroom,the cylinder has a small open tank sitting on top that looks part of the whole unit,is this the feed and expansion tank or main cold water tank ,i do not have access to the loft as neighbours are on hols?all taps look to mains fed,and have normal system boiler.
any help as to what this small tank is ,greatly app.
thanks

 

[JohnD]

If it's the same diameter at the cylinder, it's probably the cold water tank that feeds the cylinder. You should be able to tell by looking to see what pipes come out of it.

 

[namsag]

Fortic cylinder , do any of your heating pipes head up into the neighbours . If not you have a primatic fortic which means the little tank on top fills th cylinder which then fills heating circuit and keeps them seperate with a air bubble.. If pipes head up to neighbours you may have a header tank up there and then it is an indirect fortic

 

[kevplumb]

 

[finks]

many thanks all