ESCO Air Conditioning Practice Exam

When connecting copper to steel, the recommended brazing filler alloy is a 33% silver alloy. Silver-based brazing alloys are preferred for joining copper to steel due to their excellent wetting properties and ability to create strong, reliable joints. The 33% silver alloy is specifically designed for this type of joint as it provides a good balance of flow characteristics and strength, making it the ideal choice for this application.

Options B, C, and D are not the recommended brazing filler alloys for connecting copper to steel. These higher silver content alloys are not necessary for this specific joint and may result in excessive silver buildup or other issues during the brazing process. Option A, the 33% silver alloy, is the most suitable choice for ensuring a successful and reliable connection between copper and steel in air conditioning applications.