What is the minimum required soldering distance in inches from plastic to metal "compression" on a hydronic line?

The minimum required soldering distance from plastic to metal compression fitting on a hydronic line is indeed 18 inches. This guideline is in place to prevent any heat from the soldering process from damaging the plastic component. Excessive heat can cause the plastic to deform or lose its structural integrity, which can lead to leaks or failures in the system. Maintaining this distance ensures a safe working environment and compliance with plumbing codes that protect both the materials involved and the broader system's efficiency.

Understanding this requirement is crucial for anyone involved in HVAC systems and hydronic applications because it helps practitioners implement best practices for installation and maintenance, ensuring lasting performance and safety.