HVAC Journeyman Practice Exam 2026 - Free HVAC Practice Questions and Study Guide

The correct choice emphasizes the importance of adhering to the manufacturer's instructions when fabricating and installing a furnace plenum. Manufacturer's instructions provide specific guidelines and requirements based on the design and functionality of the furnace, ensuring that the plenum will operate efficiently and safely. Following these instructions helps maintain warranty requirements, ensures compliance with safety standards, and minimizes potential operational issues related to airflow and efficiency.

While considerations such as the size of the plenum, craftsmanship, and the arrangement of electrical wiring are also important, they are secondary to the manufacturer's specifications. These specifications are tailored to the specific furnace model, taking into account airflow dynamics and overall system performance, which are crucial in HVAC systems. By prioritizing the manufacturer's instructions, the proper functioning and longevity of the heating system are upheld.