What is a recommended practice when installing conversion fittings?

Permanently installing conversion fittings using a thread-locking chemical is a recommended practice because it ensures a secure and leak-free connection. Thread-locking chemicals provide a strong bond that can withstand the vibrations and thermal expansion often encountered in HVAC systems. This increases the reliability of the installation, reducing the risk of leaks that could lead to inefficiencies or equipment damage over time. Such chemical compounds typically resist loosening from vibrations, which is essential for the longevity of the fittings in an HVAC application.

Other options may not provide the necessary permanence or reliability required in HVAC systems. For example, using no thread-locking chemicals could lead to connections loosening over time, while temporary installations do not ensure the integrity and safety required for proper functioning. Lastly, using duct tape is not an appropriate practice for sealing HVAC connections, as it lacks the durability needed for long-term performance.