2. The water-air linkage device is malfunctioning. Solution: Replace the water-air linkage device.
3. There is scale or carbon deposit in the copper tube of the heat exchanger. Solution: Clean the copper tube of the heat exchanger
4. Gas filter and pressure reducing valve, there may be scale in the pipeline. Solution: Can clean up fire and water courses.
5. The control board is faulty, this is a fault of the high-end machine. Solution: Ask a professional water heater repairer to come to repair and troubleshoot.