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This post was last edited by Reichert-Li Zongsheng on 2022-10-10 at 15:58. Introduction: The commissioning and startup of centrifugal pumps are types of work that require specific skills. There are always contractors interested in commissioning and startup tasks who argue that since they can purchase and install the pumps, they are able to commission, start up, and operate them. This is incorrect. Debugging, startup, and operation skills are usually independent of operators and professional debugging companies. Some supplier representatives may have extensive knowledge of pump commissioning and operation, whereas other supplier representatives may lack such knowledge and experience. Challenges during startup: To properly start/debug the pump, it is sometimes necessary to modify the pump and related systems. Some well-known examples are: 1) Incorrect configuration of instruments and control systems; 2) The lack of spare parts for pipelines that need to be reconfigured is a well-known issue during startup, which can lead to significant delays. For some pump sets, providing a uniform bolt tightening torque can be a problem. Some flange connections in the pump, especially those of pipeline pumps, may require inspection and re-tightening of the bolts. During debugging/startup, the isolation valves and devices are sometimes not removed, which can lead to severe damage. The use of prototype pumps without operational performance is generally not encouraged. However, sometimes they have to be used. When using a new model of pump for the first time, a careful plan should be developed for the commissioning of these pump systems, with appropriate margins and tolerances included. Since the main power generation equipment or the main power transmission system is usually located on the critical path of a project, temporary power generation facilities can offer significant advantages and provide great flexibility in terms of commissioning/start-up. Real and thorough performance tests of the pumps – especially the prototype pumps – are carried out in the manufacturer’s workshop to eliminate any potential issues. This can save a great deal of time during debugging and startup. At the same time, it is possible to **reduce the high repair costs that may arise on-site (on-site repair costs are usually more than three times the cost at the manufacturer’s factory). Challenges in lubrication: Pumps of various models, types, and sizes are used in different factories or facilities. Some pumps may be lubricated with grease, but large, critical pumps usually require a dedicated lubrication system. Lubrication issues and bearing problems related to lubrication are frequently reported during debugging and startup. Regarding lubrication, the following key factors should be carefully checked and verified: 1) the properties of the grease/oil (such as viscosity), 2) the amount of grease/oil used, 3) detailed information on the oil/grease system, 4) the operating conditions of the oil system (temperature, pressure, flow rate, etc.), 5) the cleanliness of the lubrication system. Insufficient lubrication can lead to bearing damage. This rate of damage can be very rapid (**reducing the service life of the bearings**). Furthermore, insufficient lubrication can cause the bearing to change color and significantly reduce its mechanical strength. Insufficient lubrication and the associated thermal effects can manifest in many different ways, such as shiny areas and glassy surfaces, which can be observed during a thorough inspection of the bearings. Therefore, it is necessary to ensure that the centrifugal pump is properly lubricated during startup. Other challenges: There has always been a lot of attention paid to large, critical pumps. Therefore, the inspection of small and medium-sized pumps is rather casual. Ball bearings and roller bearings are used in small and medium-sized pumps, and due to improper installation, misadjustment, careless starting, or incorrect operation, they usually do not reach their expected service life. The main causes of early failure in rolling bearings are mechanical damage (such as due to rotor misalignment), lubrication problems, and material defects. Some rolling bearings even fail during startup. High-quality bearings, such as those with ceramic rolling elements, offer excellent reliability and a long service life. One example is the modern ball bearing with a special stainless steel ring and silicon nitride ceramic balls. However, only a small portion of modern pumps are equipped with these advanced bearings. The installation tolerance (tightness) of bearings is usually determined by the pump’s load and speed, and it has a significant impact on the pump’s performance, operation, and reliability. When the bearing is installed on the pump shaft, a force is applied to the bearing, thereby preloading its precise structure. If the bearing’s fit with the shaft is too tight, the bearing may be preloaded internally. This puts a high load on the rolling elements, and the deformed bearing housing bore exerts radial pressure on the outer ring of the bearing. Some rolling bearings can only withstand a limited amount of misalignment. This is a key consideration for proper debugging/startup. The dimensions of the bearing housing bore and the shaft that fits into it may be inappropriate, or they may be tapered or deformed. These defects can lead to premature failure of the bearings. For example, bearing rings may develop defects under load, and cracks may appear on the bearing raceways. Foreign objects and debris can lead to a high wear rate. Insufficient bearing sealing, dirty lubricant, and improper flushing during pre-commissioning can all lead to debris and dirt entering the system. These debris and foreign objects will **reduce the expected lifespan of the bearings**. Shock damage during delivery, installation, or commissioning may cause minor defects, which can develop into major defects over time.