A system boiler is a type of boiler that is commonly found in larger homes with greater demands for heating and hot water. It works together with a hot water cylinder to provide central heating and hot water to homes. Unlike combi boilers, which can only heat water on demand, system boilers can provide a constant supply of hot water throughout the home. System boilers are completely different from combi boilers as they are not connected to the cold mains. Instead, a coil in the cylinder carries the central heating water at high temperature through the cylinder, heating its contents, allowing the now heated water to be transferred to multiple taps and showers at once. They can usually heat both the radiators in the home at the same time as the cylinder, ensuring no loss of comfort.

System boilers use the mains as a heat source to boil the water required to keep homes warm and comfortable. They are best suited to larger homes with several radiators and bathrooms, which always create more demand for hot water. System boilers are enclosed, so work at mains pressure, while heat only boilers deliver hot water using gravity as they are not under pressure. If you don’t have high water pressure where you live, a system set-up might not work very well.

The advantages of a system boiler over combi boilers and heat only boilers include a larger supply of hot water, the ability to store large quantities of hot water for later use, and compatibility with solar thermal systems. System boilers are also a space-saving alternative to regular boilers as they are built with the expansion vessel and pump built in.

In summary, a system boiler is a type of boiler that works together with a hot water cylinder to provide central heating and hot water to homes. It is best suited to larger homes with several radiators and bathrooms, and it provides a constant supply of hot water throughout the home.