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1. If the exhaust temperature of the main unit is too high, and the temperature in the machine room is within the acceptable range as well as the oil level is normal, first check whether there is a fault with the temperature sensing element of the machine; this can be done by using another temperature measuring instrument for verification. If it is confirmed that the temperature sensing element is functioning properly, then check the temperature difference between the inlet and outlet of the oil cooler, which should normally be between 5–8°C. If the temperature is above this range, it indicates insufficient oil flow, a blockage in the oil circuit, or a thermostat valve that has not opened fully. It is necessary to check the oil filter. In some models, there is a mechanism for adjusting the oil flow; in such cases, adjust it to its maximum setting first. Check whether the thermostat valve is functioning properly by removing its valve element and blocking one end of the valve, thereby forcing all the oil to pass through the cooler. If these methods do not resolve the issue, then it is possible that there are foreign objects blocking the oil circuit. If the temperature difference is below the normal range, it may be due to poor heat dissipation. Check whether there is insufficient water flow into the coolant unit, whether the temperature of the incoming water is too high, whether scale has formed in the water circuits of the cooler, whether there is oil residue in the oil circuits of the cooler, whether the radiator is too dirty, whether there is oil residue inside the radiator, and whether the cooling fans are functioning properly. If the temperature difference is within the normal range but the machine still runs at high temperatures, it indicates that the heat generation in the machine head exceeds normal levels. It is necessary to check whether the machine is operating under excessive pressure, whether the oil used is inappropriate, whether the oil has deteriorated in quality, whether there are problems with the bearings in the machine head, or even friction at the end faces. Additionally, for those equipped with a fuel cut-off valve, it is necessary to check whether there is any malfunction in it; a faulty fuel cut-off valve usually causes the machine to shut down as soon as it starts operating, with the temperature rising sharply. 2. The diagnostic steps for low exhaust pressure (low air volume) are as follows: (1) Check whether the manual valves for the \"pre-separation\" and \"post-separation\" stages sowie the pressure gauge are leaking; if there is a leak, replace the manual valve or fix the leakage issue ； (2) Check whether the regulating solenoid valve is leaking air; if so, rectify the fault ； Replace the control solenoid valve if necessary ； (3) Check for leaks in the piping. If so, the leak point must be identified and eliminated ； (4) Check whether all butterfly valves are open. If so, check the butterfly valve mechanism and solenoid valve ； Check whether the solenoid valve is leaking air; if so, identify the cause and it may be necessary to replace the solenoid valve ； (5) Check whether the regulator is working properly; if there are issues, replace the solenoid valve or readjust the pressure switch ； Check whether the upper and lower limits of the pressure switch are normal; if so, readjust the pressure switch, and replace it if necessary. 3. The diagnostic steps for excessively high exhaust temperature are as follows: (1) Check whether the ambient temperature and exhaust pressure exceed the specified limits; if so, adjust them to the specified values ； Check whether the lubricating oil is clean and the oil level is normal; if so, replace the oil or top up the amount of oil ； Check whether the lubricant grade is correct; if so, replace it with the correct grade of lubricant. (2) Has the fan airflow decreased? If so, check the fan motor speed and whether the exhaust outlet is blocked ； After inspection, check whether the exterior of the cooler is clean, and clean the outer surface of the cooler. (3) Check whether the environment has an impact on the intake and exhaust air of the unit; if so, eliminate external factors to ensure normal ventilation of the unit. (4) Check whether the temperature control valve components are damaged; if so, replace them ； Check whether the solenoid valve and solenoid coil are damaged ； Check whether the solenoid valve diaphragm is damaged; if so, replace the coil and the diaphragm. (5) Replace the oil filter element. 4. The diagnostic steps for high oil consumption by the compressor are as follows: (1) Check whether the condensed water discharged by the drain valve contains a high amount of oil; if so, examine for leakage points within the unit and eliminate them ； Check whether the compressor oil level is too high; if so, lower it ； (2) Is the opening pressure of the minimum pressure valve normal? If so, eliminate the fault; otherwise, it is necessary to replace the valve ； Check whether the return oil pipe is blocked; if so, clean or replace it ； (3) Replace the oil separator element. 5. Clogged fuel lines, insufficient fuel injection, short lifespan of the fuel filter and oil separator components, and high operating temperatures. Cause analysis of malfunctions: All screw compressors utilize a closed-loop circulation system for cooling lubricating oil. Since they operate at relatively high temperatures for extended periods (typically between 75 and 88°C), various degradation phenomena may occur, such as carbon deposition, scaling, and acidification of the oil to varying degrees. Due to factors such as carbon buildup, it can lead to damage to the solenoids and temperature control valves in the oil circuit, blockages in the oil circuit, and poor heat exchange performance. The solution is to perform maintenance on the oil circuit system by replacing the lubricating oil, air filter, oil filter, and other related components. In the case of water-cooled models, the oil circuit system should be soaked in a scale remover. When cleaning the oil circuit, a carbon deposit cleaner should be used. Store 45.46 m’ of compressor oil in each machine, and add 4.546 m’ of the concentrate. First, make sure enough compressor lubricating oil is drained so that the liquid can be added to the storage tank. Then run the compressor continuously for 40 to 60 hours. To prevent the redeposition of suspended pollutants, it is necessary to completely drain the lubricating oil from the compressor while the oil is still hot in order to achieve the best results. 6. Analysis of the causes and solutions for oil leakage at the outlet of screw compressors (1) Excessively high oil level, too much oil injected. After relieving the pressure, drain the oil to the normal level ； (2) The return oil pipe is blocked. It can be checked and replaced ； (3) The installation of the oil return pipe (the distance from the bottom part of the oil separation element) does not meet the requirements; it can be adjusted again ； (4) The exhaust pressure is too low during unit operation; this phenomenon does not occur because the pressure in the air storage tank remains high ； (5) Internal damage to the oil distiller tank; it can only be detected through disassembly for inspection ； (6) Oil has deteriorated or been used beyond its expiration date ； (7) If the return oil check valve loses control, oil will flow back into the oil fine separator after the unit stops operating; this will result in oil leakage when the unit is started again ； (8) Damage or rupture of the oil purifier element. 7. Analysis of the reasons for degraded air compressor oil and a shortened oil change cycle: The original air compressor room in the machinery factory was located below the electrostatic precipitator and flue gas desulfurization units, resulting in a poor environment with high dust levels in the air. During operation, air compressors frequently experience problems such as oil degradation and clogged filters, which leads to a shortened oil change interval and an **increase in operational and maintenance costs**. Treatment method (1): Select the appropriate lubricant and establish a comprehensive management system for the procurement, inspection, and acceptance of lubricants for air compressors. (2) Determine the appropriate oil supply amount. If too much lubricating oil is supplied, carbon deposits are likely to form. However, it cannot be too low either; insufficient oil supply leads to poor lubrication of the cylinder block and rotor, increasing the risk of cylinder scoring. (3) Establish a minor maintenance cycle focused on inspection and cleaning. Fully synthetic oil (the highest quality air compressor oil): must be replaced every 6,000–8,000 hours. 8. Analysis of the reasons for compressor not loading: (1) The pressure in the pipeline exceeds the rated load pressure, causing the pressure regulator to shut off. (2) The minimum pressure valve malfunctions; it does not operate during loading, preventing high-temperature compressed air from entering the cooler. (3) There is a leak in the control pipeline between the separator and the unloading valve; inspect the pipeline and connections, and repair any leaks that are found. Handling method: If the gas source pressure exceeds the rated value, no action is required. When the pressure in the pipeline is lower than the setting pressure of the pressure regulator, the compressor will activate automatically. If the minimum pressure valve fails, remove it for inspection and replace it if necessary. If there is a leak in the control pipeline between the separator and the unloading valve, inspect the pipeline and connections; if a leak is found, it must be repaired.