热水锅炉是生产热水、用以供热的锅炉。热水锅炉与蒸汽锅炉都以水为工质，两者的很大区别是，后者生产蒸汽，前者生产热水。 热水锅炉有低温热水锅炉和高温热水锅炉之分。各国对高温水和低温水有不同的温度分界，我国以120。C为分界温度，亦即出水温度高于120。C的为高温热水锅炉，否则为低温热水锅炉。 热水锅炉系列的参数范围为：额定热功率0.1一116MW，允许工作压力0.4—2.8MPa，额定出水温度95—180。C。热水锅炉因其工作压力低、无需水位监督和控制，因而其结构较为简单、运行维护方便、制造简便。但其工作也有一些特殊问题：必须保证锅炉热水不汽化，以避免产生水击;低温受热面的内部氧腐蚀和外部酸腐蚀更为严重;突然停电时，锅内水不流动而产生汽化等。这些问题都必须在热水锅炉的结构设计、制造和运行维修中加以考虑。 蒸汽锅炉和热水锅炉从“锅”和“炉”的结构上没有太大的区别，但还是有一定的区别，如果型号一样(参数肯定不一样)，其区别有：蒸汽锅炉上锅筒内装不同，蒸汽锅炉有汽水分离器，而热水没有;蒸汽锅炉有主蒸汽输出管道，而热水锅炉是热水输出管道;蒸汽锅炉有给水管道，只有回水管道从下集箱进入，补给水也是从这根管道中补进的;热水锅炉没有水位计，而蒸汽锅炉有。 另外，蒸汽锅炉需要耐压高，提供高压蒸汽可达400摄氏度，4个大气压左右，对炉体要求高，制造工艺要求高。 热水锅炉提供70摄氏度的热水，有常压和有压之分，但压力比蒸汽锅炉小。 从用途上面来讲，蒸汽锅炉压力在0.1MPa上高达几百MPa，向外送出的是蒸汽。多用于工业，中高压的主要用于火力发电厂。成套性强、技术含量高、机组多自控，投资大。我国对蒸汽锅炉管理较严，强检、年检的类别多。热水锅炉压力在0.1MPa以下，向外送出的是热水。多用于生活，投入小，管理费用较低、安全。
Hot water boiler is the production of hot water, to the heating boiler. Hot water boiler and steam boiler with water as working substance, is a large difference of the two, the latter steam production, the production of hot water. Hot water boiler with low temperature hot water boiler and high temperature hot water boiler. For high temperature and low temperature water have different water temperature boundary, our country in 120. C for boundary temperature, water temperature higher than 120. C for high temperature hot water boiler, or for low temperature hot water boiler. Rated parameters of hot water boiler series are as follows: 0.1 a 116 mw thermal power, allowing work pressure 0.4 2.8 MPa, rated water temperature 95-180. C. Hot water boiler because of its low working pressure, no need for water level monitoring and control, and its structure is simple and convenient operation maintenance, easy to manufacture. But the work also have some special problems: must ensure that the boiler hot water evaporation, to avoid water hammer; Low temperature heating surface of external and internal oxygen corrosion acid corrosion is more serious; Sudden power failure, pan in the inland waters flow and vaporization, etc. These problems must be in the hot water boiler structure taken into consideration in the design, manufacture and operation maintenance. Steam boiler and hot water boiler from the "pot" and "furnace" on the structure of not big difference, but there are some difference, if the model (parameters) certainly not the same, the difference is: steam boiler drum within different, steam boiler steam separator, and hot water is not; Steam boiler main steam output pipeline, and hot water boiler is hot water output line; Steam boiler feed water pipe, only return water pipe from the fixation of chest, make-up water is covering from the pipeline; No hot water boiler water level gauge, and steam boiler. In addition, need high pressure steam boiler, provide high pressure steam up to 400 degrees Celsius, about four atmospheric pressure, high requirement to the furnace body, high manufacturing process requirements. Hot water boiler to provide the hot water of 70 degrees Celsius, with normal pressure and pressure, but pressure is smaller than the steam boiler. From the purpose above, the steam boiler pressure in several hundred MPa to 0.1 MPa, to send out the steam. More used in the industry, high pressure is mainly used in thermal power plants. Complete sets of strong, high technical content, unit control, large investment. Of steam boiler management is strict, the category of the strong test, the annual inspection. Hot water boiler pressure below 0.1 MPa, sent out of hot water. For life, small investment, low management cost, safety.