SystemZone makes it very easy to install and operate multiple boilers
The two outside Systemzones are fed by the heat sources. As these operate independently of each other, any combination of boilers can be used to match the load to the optimum operating level of the boilers. Heat sources can be taken off line for maintenance or replacement without interrupting service.
The central Systemzone takes the output from the heat sources and delivers it to the heating zones - four in this example. These can be further subdivided into additional zones by using more Systemzones.
Using multiple boilers rather than one or two large ones can greatly reduce the initial capital cost. For instance, using balanced flue boilers can save the expense of a high chimney.