Light detection method is the use of light on the small hole of the strong visual acuity, the system tightness of the spiral duct qualitative detection method. The test method is in a certain length of the spiral duct, in the dark environment, in the spiral duct with a voltage of not more than 36V, power of 100W or more with a protective cover of the bulb, from the end of the spiral duct slowly Move to the other end, the test if the spiral duct can be observed outside the light, then the spiral duct has a leak, and the air leakage of the spiral duct to repair.

        System Spiral duct leakage detection method using sub-detection, summary analysis method, the system is not allowed to have a number of spiral duct ducts obvious light leakage, low pressure system Spiral duct every 10 meters seam, Not more than 2, 100 m seam average of not more than 16; medium pressure system spiral duct for every 10 joints, the leakage point of not more than 1, 100 meters seam average of not more than 8 for qualified.