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I have a hot water heating system with 3 zones: domestic hot water with a dedicated pump to an indirect HWH, and two heating loop circuits off a second pump. If I add a loss loss header with a 3rd pump on a primary loop and the primary loop pumps (on the return to the boiler) towards the expansion tank, but the other pumps pump away (on the supply lines), will the heating zones maintain constant pressure, IE: take advantage of the pumping away concept?