The line set must be brazed, silver soldered, or connected using another method, such as crimp fittings or flares.

When brazing, use a 15% silver brazing rod and flow inert gas, such as nitrogen, through the tubing to reduce oxidation inside the tube. Nitrogen should flow through the tubing at 3 CFH. There should not be any pressure within the tubing. The nitrogen is just purging the air while heating the tubing for the braze rod to melt and seal the joint. When brazing, no additional flux is required. The phosphorus in the braze rod acts as the flux, so no acid enters the tubing. Use an air acetylene or oxy-acetylene torch for high temp brazing.

Use a propane or Mapp gas torch for silver soldering. When silver soldering, use Stay-Brite 8 and flux. You do not want acid inside the tubing. Therefore, use the least flux possible. When silver soldering, there is no need to flow nitrogen through the tubing because the tube does not become hot enough to create oxide.