Vacuum Hot Water Boiler Boiler with oil/gas burner | Central heating boiler | Boiler for heating Vacuum hot water boilers also named vacuum phase change hot water boiler. There is a vacuum condition inside, fill heat medium water in furnace and heat these water through oil/gas. Through heat exchange, the heat inside the boiler is transfered to outside water. Transfer medium: hot water Thermal Capacity: 0.3-7 mw 300-7,000 kw/h 200,000-6,000,000 Kcal/h Efficiency: 99.9% Available Fuel: heavy oil, diesel, furnace oil, biogas, NG, CNG, LNG, LPG, dual fuel Applied Industries: heating & drying like: food, beverage, wood chamber, greenhouse, building heating, hotel, school, etc