Core body shapes and sizes should be consistent with the drawings. In addition to drawings, the parts of the appearance of the product should comply with good practice.

Core fin welding rate should be greater than 98%; Fin lodging is not allowed more than two, and each place can not be greater than 1cm2; Does not allow the surface bumps, scratches, peeling paint and other defects detrimental to appearance.

Tightness

Leak detection with helium leak detector should be no reaction. Helium leak detector leak detection accuracy equivalent to the test pressure is 0.7MPa R134A annual leakage rate when not more than 2 grams.

Vacuum resistance

2KPa test pressure to vacuum pressure load, each time to keep 5min, three times, the pressure increased to allow no more than 500Pa/min.