Pressure control safety device: it can automatically cut off power in case of exceeding the set pressure during use. Pressure relief safety device: when the pressure in the boiler exceeds the safety value due to the failure of the pressure limiting safety device, the pressure relief mechanism will work to automatically exhaust and relieve the pressure around the boiler to ensure that no accident of boiler explosion will occur. Pressure limiting safety device: when the pressure in the boiler increases to the upper limit, the pressure limiting vent valve will automatically exhaust and limit the pressure.