Residential HVAC Installation Practice Exam

Copper tube is recommended for connecting lines to the vacuum pump and gauge set for accurate testing because it is a highly conductive material that allows for more accurate readings. Aluminum tubing can be too flexible and can potentially leak air, while steel pipe may be too rigid and not provide accurate pressure readings. Plastic piping is not recommended as it can be easily damaged and may not hold up to the pressure of the vacuum pump and gauge set.