"Tony Eva" wrote in message ...
Alex wrote:
System boilers are used in conjunction with pressurised hot water tanks
such
as megaflow

Are you sure? I have a Glow-worm 30SXI in a conventional sealed system
with indirect HW cylinder. It seems to work perfectly well.

The system is too new for me to comment on the boiler's reliability, but
otherwise I am very happy with it.

A system boiler has:
- an integral pressure vessel
- integral pump.

Heating boilers:
are basic boilers with no pump or pressure vessel, that usually can be
pressurised, by a kit or external pressure controls and pump or can be open
vented. Most buy them to be open vented.

A combi is a system boiler with and added water section.



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