Hi,
Their respective circuit include the main loop, so they are oversized in the sense that zone TDH + main circuit loop.
i.e,
Main loop head = 10 Bar,
Zone 1 head = 15 Bar
Zone 2 head = 20 Bar
Zone 3 head = 25 Bar
Pump Duty
Zone 1 Pump = 25 Bar
Zone 2 Pump = 30 Bar
Zone 3 Pump = 35 Bar...