A cold header is a manifold pipe that collects refrigerant from various individual circuits within an evaporator or condenser coil. It acts as a central hub that ensures the refrigerant is distributed evenly across the entire surface of the AC Coil Systems. If the cold header is poorly designed, it can cause "starving" of certain coil segments, leading to uneven cooling and reduced efficiency. In high-capacity Commercial HVAC units, the header must be precisely sized to handle the flow of liquid or gas without creating excessive turbulence. You will find these headers at the top and bottom of the indoor coils used in Mobile Home Air Handler setups. Because it is a high-pressure component, it is usually constructed from heavy-gauge copper to prevent leaks. Proper brazing at the header is one of the most technical parts of the manufacturing process for ACIq equipment. It ensures that your system operates at the exact pressure levels specified by the manufacturer.