ZOZEN Boiler has optimized the three-pass gas and oil boiler to the two-pass type. The corrugated furnace with major diameter and the threaded smoke tubes enhances the heat transfer efficiency. The thermal efficiency of the boiler reaches over 98%. Also, the low-NOx burner could control the emission below 30mg/Nm³, which meets the environmental protection policy. ZOZEN WNS series gas/oil-fired boiler is well received by industrial plants due to its compact structure and packaged delivery with convenient installation.