low air nitrogen ratio 4 2 to 1

{"cid":"91212236","title":"High Efficiency Energy Saving 350-2800 KW Gas Hot Water Boiler With 15-100% Stepless Variable Frequency Regulation","imgUrl":"https:\/\/img.chinax.com\/nimg\/cc\/89\/09ee8395cca9f2acfa27908f2a27-200x200-1.jpg","attrs":{"Price":"TO BE ENGOTIATED","Brand Name":"WONDERY","Model Number":"DWL-LNW","Minimum Order Quantity":"1 Set\/Sets","Delivery Time":"30days","Certification":"CE","Place of Origin":"Jiangsu,China(Mainland)","Payment Terms":"L\/C, T\/T","Supply Ability":"200 Set\/Sets per Year","Packaging Details":"wooden case suitable for sea transportataion or nude package","Maximum operating temperature":"90\u2103","nox emission":"<30mg\/m\u00b3","Gas pressure requirements":"2~5Kpa","weight":"410-2100kg"}}