According to the code, vent terminals for direct-vent appliances must be installed following which guidelines?

Vent terminals for direct-vent appliances must be installed according to the manufacturer's instructions because these instructions provide critical information that is tailored to the specific appliance type. Each manufacturer designs their appliance uniquely, taking into account factors such as airflow requirements, ventilation needs, and safety standards. By following the manufacturer's guidelines, installers ensure that the appliance operates safely and efficiently, adheres to warranty conditions, and meets performance specifications established by the manufacturer.

While local building codes, state regulations, and industry standards play important roles in the overall compliance and safety of mechanical systems, the manufacturer's instructions are specifically crafted to address the requirements particular to each appliance. Therefore, they serve as the primary resource for ensuring the proper installation and functioning of direct-vent appliances.