What is a system boiler and how does it work?
This design is generally fitted for central heating systems which are “sealed circuits” where the all the plumbing work connecting to cylinders is “closed”.
The fact that the water flow circuit is sealed, and not open to the surrounding atmosphere, maintains water pressure and so, combined with the fact that most of the important elements already built into the boiler, takes away the requirement for an expansion tank & feed system.
However, in some cases where the hot water cylinder is not pressurised they may require a tank for cold water.
This type of hot water & central heating is compatible with using Solar Thermal & Solar Thermodynamic Panels
The operating method is opposite to that of a Combi Boiler in that it makes use of storing water then heating it, rather than using the mains flow and heating the water as it comes into the home.