The Honeywell VP531C1000 is a normally open, 2-way pneumatic control valve designed for precise fluid flow regulation in HVAC systems. Operating within a 2–5 PSI control range, it modulates valve position to maintain accurate temperature control. With a 1/2-inch connection, 150 PSI pressure rating, and 1.6 Cv, it is commonly used in air handling units, fan coil units, and hydronic heating or cooling coils. This valve improves energy efficiency, ensures stable system performance, reduces wear, and delivers reliable, long-term operation.