In an earlier contribution to this discussion,
Paul wrote:

Hi. I have decided against buying a combi boiler. But what is the
difference between a system boiler and a primary boiler?
Thanks.

A system boiler usually has additional components - typically pump,
expansion vessel, filling loop, etc. - ready installed inside its casing. A
non-system boiler doesn't - and these components have to be supplied and
installed externally. [I assume 'primary' refers to an ordinary, non-system
boiler - but am not too familiar with the term].

A system boiler requires less effort to install - but the integrated
components are often proprietary, and more expensive to replace than the
generic components used in a conventional setup.
--
Cheers,
Set Square
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