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1. Failures of pneumatic actuators (cylinders): Due to improper assembly and long-term use, pneumatic actuators (cylinders) are prone to internal and external leaks, insufficient output force and unsteady operation, poor buffering performance, as well as damage to the piston rod and cylinder head. (1) Internal and external leaks in the cylinder are usually caused by an eccentric installation of the piston rod, insufficient lubrication, worn or damaged seals, impurities inside the cylinder, or scratches on the piston rod. Therefore, when internal or external leakage occurs in the cylinder, the center of the piston rod should be readjusted to ensure its coaxiality with the cylinder barrel ； It is necessary to regularly check whether the oil mister is working properly to ensure proper lubrication of the actuating elements ； When the sealing rings and gaskets become worn or damaged, they must be replaced promptly ； If there are impurities in the cylinder, they should be removed promptly ； If the piston rod is damaged, it should be replaced. (2) Insufficient output force and unstable operation of the cylinder are generally caused by issues such as the piston or piston rod being stuck, poor lubrication, insufficient air supply, or the presence of condensation water and impurities inside the cylinder. To address this, the center of the piston rod should be adjusted ； Check whether the oil mister is working reliably ； Is the air supply pipeline blocked? When there is condensation and impurities in the cylinder, they should be removed promptly. (3) The cylinder’s buffering effect is poor, usually due to worn buffer seals or damaged adjustment screws. At this point, the sealing ring and adjustment screw should be replaced. (4) Damage to the piston rod and cylinder head of the cylinder is usually caused by an eccentric installation of the piston rod or by a malfunctioning damping mechanism. To address this, the center position of the piston rod should be adjusted ； Replace the buffer seal ring or adjustment screw. 2. Faults in the directional control valve: Faults of the directional control valve include the valve’s inability to change direction or slow response in changing direction, gas leakage, and faults in the electromagnetic pilot valve. (1) If the directional control valve cannot change direction or does so slowly, it is usually due to poor lubrication, a stuck or damaged spring, or oil and debris blocking the moving parts. In response to this, it is necessary to first check whether the oil mister is functioning properly ； Is the viscosity of the lubricating oil appropriate? If necessary, the lubricating oil should be replaced, the sliding parts of the directional control valve should be cleaned, or the springs and the directional control valve itself should be replaced. (2) After long-term use, the directional control valve is prone to problems such as wear of the seal ring on the valve spool, as well as damage to the valve stem and seat, which leads to gas leakage from the valve, slow operation of the valve, or inability to switch directions properly. At this point, the sealing ring, valve stem, and valve seat should be replaced, or the directional control valve should be replaced. (3) If the inlet and outlet ports of the electromagnetic pilot valve are blocked by sludge or other debris, are not sealed properly, the moving core gets stuck, or there are faults in the electrical circuit, all of these can prevent the directional control valve from switching properly. For the first 3 cases, the sludge and impurities on the pilot valve and the movable core should be cleaned. Circuit failures are generally divided into two categories: control circuit failures and electromagnetic coil failures. Before checking for circuit faults, turn the manual knob of the directional control valve a few times to see if it can switch directions properly at the rated air pressure. If it can switch directions normally, then there is a fault in the circuit. During inspection, a meter can be used to measure the voltage of the electromagnetic coil to determine whether it reaches the rated voltage; if the voltage is too low, further inspection should be carried out on the power supply in the control circuit as well as the associated limit switch circuit. If the reversing valve cannot switch properly at the rated voltage, check whether the connections (plugs) of the electromagnetic coil are loose or have poor contact. The method is to unplug the connector and measure the resistance of the coil; if the resistance is too high or too low, it indicates that the electromagnetic coil is damaged and needs to be replaced. 3. Failures of pneumatic auxiliary components. The main failures of pneumatic auxiliary components include: failures of oil misters, automatic drain devices, silencers, etc. (1) Faults of the oil mister include: too small an adjustment amount of the adjustment needle, blockages in the oil circuit, and air leaks in the pipelines – all of which prevent the liquid oil droplets from being atomized. In response to this, any blockages or air leaks should be addressed promptly, and the oil dripping rate should be adjusted to around 5 drops per minute. During normal use, the oil level in the oil cup should remain within the upper and lower limits. The water accumulated at the bottom of the oil cup should be removed promptly. (2) The oil and moisture inside the automatic sewage discharge device cannot always be removed automatically, especially in winter when temperatures are low. At this point, it should be removed for inspection and cleaning. (3) When the silencer installed on the directional control valve is too dirty or blocked, it will also affect the sensitivity and switching time of the directional control valve; therefore, the silencer should be cleaned regularly.