A multi-zone air distribution system has a central fan and multiple air valves, or air flow control terminals. Each terminal mechanically restricts the local air path to regulate the air flow through the terminal. Flow controllers dynamically adjust the restriction in each terminal to regulate the corresponding flow. Each adjustment of a damper changes the flow through that terminal, but also changes the flow through every other terminal in the system. Air flow through any terminal depends strongly on the position of the corresponding damper and depends to a lesser extent on the positions of all the other dampers in the system. The degree of coupling between one damper setting and the flows through the other terminals depends on many mechanical quantities. A mathematical model is developed to represent air flows and pressure losses throughout an air distribution system. The model describes the fan, ducts and dampers as a non-linear, multi-input, multi-output system. This model enables describing the influence of a selected damper on the flow through any terminal. Analyzing at selected operating points makes it possible to compare the effects of different dampers on one flow, and to compare the magnitude of coupling at different operating points. The effect of various mechanical operating parameters on the coupling between dampers and flows is explored. The effect of the duct pressure on the coupling is especially investigated. In concrete terms, this analysis indicates the effect of duct pressure reset on air flow control performance. It pertains to exhaust systems as well as supply.