This project investigates the cause of pressure spikes in a hydronic HVAC durability test stand used to evaluate Belimo ball valves. The current rig contains 24 valves operating in opposing open–close cycles, and during mid-stroke motion the system experiences transient pressure peaks that approach the 50-psi limit of several components. These spikes are highest when valves pass through orientations near 45°, where flow restriction and turbulence intensify. To understand this behavior and support future system-level modeling, a simplified single-valve CFD model was created and validated against analytical predictions using the Darcy–Weisbach equation. The validated model was then used to evaluate pressure drops at multiple valve angles, confirming a nonlinear increase in ΔP with a peak near mid-stroke. These results establish the foundation for developing angle-dependent Cv and K relationships, which will later be incorporated into a MATLAB/Simulink model of multi-valve sequencing. The goal of this work is to identify control strategies that reduce pressure spikes by 10–30% without redesigning the valve hardware or modifying the existing test stand.