When brazing copper refrigerant lines, what is the primary purpose of flowing dry nitrogen through the tubing?
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A
To cool the joint, allowing for a faster brazing process.
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B
To prevent the formation of copper oxide scale inside the piping.
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C
To increase the pressure within the lines, which helps the brazing alloy flow into the joint.
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D
To act as a fluxing agent, cleaning the exterior of the pipe.