บอยเลอร์ - boilerthailand.com เว็บไซต์ศูนย์รวมบอยเลอร์ที่ใหญ่ ...we have some problem about hot air boiler system in the line products .This problem is have little black dust at end tube before exhaust hot air to the process tube . We check it by white cloth. After shut down we check seam welding every point by eye and ...