type of indirect tank?

[andyscott]

I plan to replace my boiler soon and am reading up on suitable boilers. My hot water tank is indirect with a coil inside it for the primary heated water to go through (excuse me if my terminology is not quite right), there is only one connection top and bottom for this coil.
Looking at information from a Glowworm Ultracom HXi installation manual it says;
“SINGLE FEED INDIRECT CYLINDERS ARE NOT SUITABLE.
The domestic hot water cylinder must be of the double feed
fully indirect coil type”

I'm a bit unsure which of these describes my tank; specifically what is a single feed indirect cylinder and what is a double? does a double have two coils?

 

[seco services]

a single feed indirect cylinder is also known as a primatic cylinder.
it has an air bubble inside that seperates the dhw not a coil.

yours is a double feed.

 

[twgas]

Double feed - one feed to domestic hot water (taps) and one to the coil (primaries, boiler, heating).

 

[kevplumb]

View media item 11263
double feed indirect

View media item 15179
single feed indirect (primatic)

 

[andyscott]

Thanks for the help guys, I thought I had the right type of cylinder but was puzzled by the single feed - I wasn't aware of the primatic type.