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

Using a solder that consists of 95% tin and 5% antimony is appropriate for soldering hydronic copper tube joints because it creates a strong, effective bond that is suitable for the temperatures and pressures typically encountered in hydronic systems. This type of solder has good wetting characteristics and does not introduce harmful lead into the system, making it safer and more reliable for use in plumbing applications.

Lead-based solder is not suitable for hydronic systems due to the health risks associated with lead. Regulations have moved towards eliminating the use of lead in plumbing to protect public health. Additionally, while brass solder is used for different applications, it is not typically specified for soldering copper pipes in hydronic systems, as the composition may not blend well with copper without potential corrosion issues. Silver solder, while effective for some specific applications, may be unnecessary for standard hydronic installations and can be more expensive than lead-free solders. Therefore, the 95% tin and 5% antimony composition is favored for its balance of performance, safety, and compliance with modern plumbing standards.