An installer sets up a single-stage copper tube boiler with a zoned distribution system as shown in Figure 1. To keep things simple, he uses the same size piping for the headers and all the distribution circuits. The distribution system operates at water temperatures where sustained flue gas condensation will not be an issue. To prevent heat migration, he installs a spring-loaded check valve at the beginning of each zone circuit, just above the header. To control differential pressure he installs a partially open globe valve across the ends of the headers. He sets the globe valve for one half turn open.

Can you identify and describe at least 5 details in this system that should be changed?