燃气热水锅炉启动前进水速度不宜太快，一般冬季不小于4h，其他季节不小于2 ~ 3h，尤其在进水初期应缓慢。燃气热水锅炉的进水温度一般为50-90℃，因此进入汽包的给水温度与汽包壁温相差不超过40℃。对于没有有效冷却的燃气热水锅炉，进水温度可与汽包壁温相比较，否则进水速度应减慢。
The water speed of gas-fired hot water boiler should not be too fast. Generally, it should not be less than 4H in winter, and not less than 2 ~ 3H in other seasons, especially in the early stage of water inflow. The water inlet temperature of gas-fired hot water boiler is generally 50-90 ℃, so the difference between the water supply temperature entering the drum and the wall temperature of the drum is not more than 40 ℃. For the gas-fired hot water boiler without effective cooling, the water inlet temperature can be compared with the drum wall temperature, otherwise the water inlet speed should be slowed down.
When the water enters the drum, it always contacts the lower half of the drum first. If the difference between the temperature water supply and the drum wall is too large, the water speed is fast, the drum, the upper and lower walls, the inner and outer walls will produce a big difference in expansion, the drum will cause more additional pressure, leading to the deformation of the drum and serious cracks.
Because the drum wall is thick, the expansion speed is slow, while the tube connected to the drum wall is thin and the expansion speed is fast. If the water inlet temperature of the gas-fired hot water boiler is too high or the water inlet speed is too fast, it will cause uneven expansion, crack of the welding joint, and damage the gas-fired hot water boiler.
压力管的直径一般取7 ~ 13mm(对于水、蒸汽)，其长度不宜过长(<60m)。如果压力管的直径过小，长度会影响压力测量的动态传递，增加动态误差。内径大，不易维修，安装方便。压力管线不能水平敷设，以防止气泡(测量液体时)和水柱(测量气体时)的积聚。出口必须垂直于介质流。不允许倒角、法兰和毛刺进入口内。测量电加热蒸汽锅炉的液体压力时，应将压力出口从管段下部抽出，防止液体中的气体进入压力管道。测量气体压力时，应将喷嘴从管段顶部抽出，以防止灰尘和水滴进入压力导管。
The diameter of the pressure pipe is generally 7 ~ 13mm (for water and steam), and its length should not be too long (< 60m). If the diameter of the pressure pipe is too small, the length will affect the dynamic transmission of the pressure measurement and increase the dynamic error. Large inner diameter, not easy to maintain, easy to install. Pressure lines should not be laid horizontally to prevent the accumulation of air bubbles (when measuring liquids) and water columns (when measuring gases). The outlet must be perpendicular to the medium flow. Chamfers, flanges and burrs are not allowed to enter the mouth. When measuring the liquid pressure of the electric heating steam boiler, the pressure outlet shall be drawn out from the lower part of the pipe section to prevent the gas in the liquid from entering the pressure pipe. When measuring the gas pressure, the nozzle should be pulled out from the top of the pipe section to prevent dust and water from entering the pressure conduit.、
The installation position of pressure gauge of electric steam boiler (pressure transmitter) shall meet the environmental conditions (temperature, humidity, vibration, etc.) used by the instrument, so as to facilitate observation, maintenance and safety. Thermal insulation layer must be laid in the high-temperature medium pressure pipeline to prevent scalding when flushing the pipeline.
The penstock must be equipped with a needle valve operation (failure to cut off the penstock), a secondary needle valve (active instrument put into use, stop, change), a condensation coil and an elbow (high temperature isolation of elastic elements from the medium, convenient addition of sealing plate packaging), a drain valve and a drain pipe, etc. For special pressure measurement, the pressure pipe must also be equipped with exhaust valve, isolation chamber, etc.