1.when atmospheric pressure is used, the atmospheric hot water boiler is directly closed to the tap water or heating system under normal pressure. That is to say, the exhaust pipe connected with the atmosphere on the boiler body is used as a return pipe, so that the boiler body is always in full water pressure state. There are two kinds of hazards in this closed cycle: first, when the water temperature is too high, the steam generated can not be discharged, so the pressure will continue to rise, explosion and leakage accidents can occur at any time. Second, even if the boiler water temperature is not high, will not produce a large number of steam, but because of the role of circulating pumps, the boiler body to withstand hot water circulating pressure is higher. The atmospheric hot water boiler is installed on the first floor or basement, and the hot water tank is installed on the roof of the building. The same way is to use the exhaust pipe connected with the atmosphere on the boiler body as a return pipe. Although the boiler itself does not withstand the pressure exerted by the ring pump, the boiler bears the hydrostatic pressure provided by the high water tank at all times. The higher the floor, the higher the hydrostatic pressure. The diameter of the exhaust pipe installed on the main body of the atmospheric hot water boiler is too small, and some of the exhaust pipe is only 20mm in diameter, so the steam generated in the boiler can not be discharged quickly, which makes the boiler body bear certain pressure and has certain danger. During the inspection, it was found that when the rated power of an atmospheric hot water boiler is 300,000 calories and the exhaust pipe on the main body is 20mm, the steam pressure generated in the boiler can reach 0.15Mpa due to insufficient exhaust capacity. The greater the rated thermal power of the boiler, the greater the steam pressure in the furnace and the greater the risk. Changing the atmospheric hot water boiler to a steam boiler means that the exhaust pipe connected with the atmosphere is directly installed on the steam-using device and the control valve is installed on the exhaust pipe. Others, after installing the control valve on the exhaust pipe, take boiled water or take a bath with hot water directly from the boiler, which is extremely unsafe. . If the boiler shuts down the control valve in operation, the atmospheric hot water boiler is prone to explosion under the condition of rising pressure, and the consequences are unthinkable.
2.Poor quality, slow development of atmospheric hot water boiler manufacturers rapid development, the emergence of products in excess of demand, some manufacturers weak technical force, poor manufacturing quality, and the competition between manufacturers is very fierce, mutual price pressure, some manufacturers even jerry-built. The design is not standardized. Compared with pressurized boiler, atmospheric hot water boiler has remarkable characteristics, especially in thermal and hydrodynamic aspects, so the structure design of atmospheric hot water boiler should conform to its own characteristics. However, the design of atmospheric hot water boiler is not standardized at present. Thermodynamic calculation and hydrodynamic calculation are not carried out at all. The design of atmospheric hot water boiler is basically changed to open form on the basis of pressurized boiler. Other structures are duplicated as original, resulting in poor water circulation and waste of energy. The production technology is weak and the manufacturing quality is poor. According to the relevant data, some manufacturers have very weak technical force, and some manufacturers even have no boilers professional technicians, who know little about the theory of atmospheric hot water boilers. Some do not have any design data, inspection data, some manufacturers only copied the drawings of pressurized hot water boiler, to change it into open. As a result, the poor quality of boiler manufacturing causes accidents. Installation is chaotic. In recent years, more and more teams are engaged in the installation of atmospheric hot water boilers. The installation team is complex and the installation quality is difficult to control.
Therefore, the problems existing in the design, manufacture, installation and operation of atmospheric hot water boilers affect the safety and reliability of atmospheric hot water boilers.
（1）Boiler design and manufacturing departments should conduct in-depth and meticulous research on atmospheric hot water boilers. According to their combustion, heat transfer, flue gas flow and hydrodynamic characteristics, they should design atmospheric boilers with characteristics of atmospheric pressure operation and heating system to ensure that atmospheric hot water boilers can maintain atmospheric pressure or micro-pressure state under any conditions.
（2）Design a reliable system suitable for the characteristics of atmospheric hot water boiler system to ensure the safe and reliable operation of atmospheric hot water boiler heating system;
（3）strengthen daily operation and management of atmospheric hot water boiler. Establish boiler Management System Department boiler worker training, to avoid low level of operators, improper operation caused serious accidents.
Add: East of Jinshui Road, Zhengdong New District Zhengzhou City