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Analysis and treatment of common faults in the cold storage refrigeration control system 1. The solenoid valve coil burnout phenomenon is that the low-voltage negative solenoid coil shell has no heat sensation, and a short circuit is measured with a multimeter RX10. The solution is to replace similar coils individually. The phenomenon that the valve core is stuck is that there is no opening and closing action, a. When placed in the closed position, the low pressure is negative and there is no refrigeration cycle. b. If left in the open position, the high and low pressures will quickly balance out after parking, which may easily cause liquid to leak out when driving. The solution is cleaning. The phenomenon of lax closing is that the high and low pressures are quickly balanced during a period of parking, and liquid sometimes leaks out under certain circumstances. The solution is to replace the iron core. The phenomenon of oil blockage and dirty blockage means that there is a cold feeling or frost in the slightly blocked state, until it is fully blocked and the low pressure is low, affecting the refrigeration cycle. Pressure controller does not produce action: The phenomena are (1) Electrical circuits are faulty or misconnected, (2) Electrical contacts are frayed or stuck, (3) Mechanical operating components fail, (4) Connection pipelines are clogged with oil, (5) No signal input, (6) There is leakage, and (11) Loss of control: The phenomena are (1) incorrect setting value, (2) positioning falling off, (3) mechanical component deformation and spring force change, (4) high and low voltage signals are connected incorrectly, and the signal tube is deformed or bent to produce internal resistance, (5) common fault analysis and treatment of the pressure controller remote cold storage refrigeration control system. The solenoid valve coil is burned out. The phenomenon is that the low-voltage negative value solenoid coil shell has no heat sense, and is measured as a short circuit with a multimeter RX10. The solution is to replace similar coils individually. The phenomenon that the valve core is stuck is that there is no opening and closing action, a. When placed in the closed position, the low pressure is negative and there is no refrigeration cycle. b. If left in the open position, the high and low pressures will quickly balance out after parking, which may easily cause liquid to leak out when driving. The solution is cleaning. The phenomenon of lax closing is that the high and low pressures are quickly balanced during a period of parking, and liquid sometimes leaks out under certain circumstances. The solution is to replace the iron core. The phenomenon of oil blockage and dirty blockage means that there is a cold feeling or frost in the slightly blocked state, until it is fully blocked and the low pressure is low, affecting the refrigeration cycle. Pressure controller does not produce action: The phenomena are (1) Electrical circuits are faulty or misconnected, (2) Electrical contacts are frayed or stuck, (3) Mechanical operating components fail, (4) Connection pipelines are clogged with oil, (5) No signal input, (6) There is leakage, and (11) Loss of control: The phenomena are (1) wrong setting value, (2) positioning loss, (3) mechanical component deformation and spring force change, (4) high and low voltage signals are connected incorrectly, signal tube deformation or bending creates internal resistance, (5) the pressure controller is far away from the compressor, causing a difference in action time. Analysis of the causes of slow temperature drop in cold storage It is a common phenomenon that the temperature in cold storage cannot drop or drops slowly. Now we will make a brief analysis of the reasons for the slow decline of the storage temperature, hoping to bring some help to the work of colleagues in the industry. 1. Cold storage has a large cooling loss due to poor insulation or sealing performance. Poor insulation performance is due to insufficient thickness of the insulation layer of pipes, warehouse insulation walls, etc., and poor insulation and insulation effects. It is mainly caused by improper selection of the thickness of the insulation layer during design or poor quality of insulation materials during construction. In addition, during construction and use, the insulation and moisture-proof performance of the insulation material may be destroyed, causing the insulation layer to become damp, deformed, or even rotten. Its insulation capacity will decrease, the loss of cold storage capacity will increase, and the drop in storage temperature will be significantly slowed down. Another important reason for large cooling losses is poor sealing performance of the warehouse, which causes more hot air to invade the warehouse from air leaks. Generally, if condensation occurs on the sealing strip of the warehouse door or the sealing of the cold storage insulation wall, it means that the sealing there is not tight. In addition, frequent opening and closing of the warehouse door or more people entering the warehouse at the same time will also increase the loss of warehouse cooling capacity. Try to avoid opening the warehouse door to prevent large amounts of hot air from entering the warehouse. Of course, when the warehouse receives inventory frequently or the purchase volume is too large, the heat load increases sharply, and it generally takes a long time to cool down to the specified temperature. 2. The surface of the evaporator is too frosted or has too much dust, and the heat transfer effect is reduced. Another important reason for the slow drop in the storage temperature is the low heat transfer efficiency of the evaporator. This is mainly caused by the thick layer of frost or too much dust on the evaporator surface. Since the surface temperature of the evaporator in the cold storage is mostly below 0°C, and the humidity in the warehouse is relatively high, the moisture in the air can easily form frost or even ice on the surface of the evaporator, affecting the heat transfer effect of the evaporator. In order to prevent the frost layer on the surface of the evaporator from being too thick, it needs to be defrosted regularly. Here are two simpler defrosting methods:: ①Shut down to defrost. That is, stop the operation of the compressor, open the warehouse door, let the temperature rise, and then restart the compressor after the frost layer melts automatically. ②Chongshuang. After moving the goods out of the warehouse, directly rinse the surface of the evaporator drain pipe with higher temperature tap water to dissolve or fall off the frost layer. In addition to the poor heat transfer effect of the evaporator caused by excessive frost, the heat transfer efficiency of the evaporator will also be significantly reduced due to excessive dust accumulation on the evaporator surface due to long-term failure to clean. 3. If there is more air or refrigeration oil in the evaporator, the heat transfer effect will decrease. Once more refrigeration oil is attached to the inner surface of the evaporator heat transfer tube, its heat transfer coefficient will decrease. Similarly, if there is more air in the heat transfer tube, the heat transfer area of the evaporator will decrease, and its heat transfer efficiency will also decrease significantly, and the temperature drop rate of the warehouse will slow down. Therefore, during daily operation and maintenance, attention should be paid to timely cleaning of the oil on the inner surface of the evaporator heat transfer tube and exhausting the air in the evaporator to improve the heat transfer efficiency of the evaporator. 4. The throttle valve is improperly adjusted or blocked, and the refrigerant flow is too large or too small. The throttle valve is improperly adjusted or blocked, which will directly affect the refrigerant flow entering the evaporator. When the throttle valve is opened too large, the refrigerant flow rate will be too large, the evaporation pressure and evaporation temperature will also increase, and the temperature drop in the warehouse will slow down. ； At the same time, when the throttle valve is too small or blocked, the refrigerant flow rate will also decrease, the cooling capacity of the system will also decrease, and the temperature drop rate of the warehouse will also slow down. Generally, whether the throttle valve refrigerant flow rate is appropriate can be judged by observing the evaporation pressure, evaporation temperature and frost formation in the suction pipe. Throttle valve blockage is an important factor affecting refrigerant flow. The main causes of throttle valve blockage are ice blockage and dirt blockage. Ice blockage is caused by the poor drying effect of the dryer. The refrigerant contains moisture. When it flows through the throttle valve, the temperature drops below 0°C. The moisture in the refrigerant freezes and blocks the throttle hole. ； Dirty blockage is caused by the accumulation of more dirt on the inlet filter of the throttle valve, resulting in poor refrigerant flow and blockage. 5. The amount of refrigerant in the system is insufficient and the refrigeration capacity is insufficient. There are two main reasons for insufficient refrigerant circulation. First, the refrigerant charge is insufficient. At this time, you only need to add sufficient refrigerant. Another reason is that there is a lot of refrigerant leakage in the system. In this case, you should first find the leakage point, focusing on checking the connections of each pipe and valve. After the leakage is found and repaired, sufficient refrigerant can be charged. 6. The efficiency of the compressor is low, and the cooling capacity cannot meet the warehouse load requirements. Due to long-term operation of the compressor, the cylinder liner, piston ring and other components are seriously worn due to serious wear and tear. The fitting clearance increases, the sealing performance will decrease accordingly, the gas transmission coefficient of the compressor will also decrease, and the cooling capacity will decrease. When the cooling capacity is less than the heat load of the warehouse, the temperature of the warehouse will drop slowly. The refrigeration capacity of the compressor can be roughly judged by observing the suction and discharge pressure of the compressor. If the refrigeration capacity of the compressor decreases, the common method is to replace the cylinder liner and piston ring of the compressor. If the replacement still does not work, other factors should be considered, and even the machine should be disassembled and repaired to rule out 1. The cold storage has a large loss of cooling capacity due to poor insulation or sealing performance. Poor insulation performance is due to insufficient thickness of the insulation layer of pipes, warehouse insulation walls, etc., and poor insulation and insulation effects. It is mainly caused by improper selection of the thickness of the insulation layer during design or poor quality of insulation materials during construction. In addition, during construction and use, the insulation and moisture-proof performance of the insulation material may be destroyed, causing the insulation layer to become damp, deformed, or even rotten. Its insulation capacity will decrease, the loss of cold storage capacity will increase, and the drop in storage temperature will be significantly slowed down. Another important reason for large cooling losses is poor sealing performance of the warehouse, which causes more hot air to invade the warehouse from air leaks. Generally, if condensation occurs on the sealing strip of the warehouse door or the sealing of the cold storage insulation wall, it means that the sealing there is not tight. In addition, frequent opening and closing of the warehouse door or more people entering the warehouse at the same time will also increase the loss of warehouse cooling capacity. Try to avoid opening the warehouse door to prevent large amounts of hot air from entering the warehouse. Of course, when the warehouse receives inventory frequently or the purchase volume is too large, the heat load increases sharply, and it generally takes a long time to cool down to the specified temperature. 2. The surface of the evaporator is too frosted or has too much dust, and the heat transfer effect is reduced. Another important reason for the slow drop in the storage temperature is the low heat transfer efficiency of the evaporator. This is mainly caused by the thick layer of frost or too much dust on the evaporator surface. Since the surface temperature of the evaporator in the cold storage is mostly below 0°C, and the humidity in the warehouse is relatively high, the moisture in the air can easily form frost or even ice on the surface of the evaporator, affecting the heat transfer effect of the evaporator. In order to prevent the frost layer on the surface of the evaporator from being too thick, it needs to be defrosted regularly. Here are two simpler defrosting methods:: ①Shut down to defrost. That is, stop the operation of the compressor, open the warehouse door, let the temperature rise, and then restart the compressor after the frost layer melts automatically. ②Chongshuang. After moving the goods out of the warehouse, directly rinse the surface of the evaporator drain pipe with higher temperature tap water to dissolve or fall off the frost layer. In addition to the poor heat transfer effect of the evaporator caused by excessive frost, the heat transfer efficiency of the evaporator will also be significantly reduced due to excessive dust accumulation on the evaporator surface due to long-term failure to clean. Common fault analysis and troubleshooting of cold storage and troubleshooting (1) The exhaust pressure is too high 1. The cooling water volume of the water condenser is insufficient or the cooling air volume of the air-cooled condenser is insufficient. 2. The scale or oil on the surface of the condenser tube cluster is too thick, causing heat dissipation difficulties. 3. There is air in the refrigeration system. 4. Too much refrigerant is charged. 5. The exhaust pipe valve fails, causing the pressure to be too high. 1. Check whether the water valve is fully open, increase the water supply or check 2. Whether the motor voltage, speed, and transmission belt are loose. 3. Clean the scale and scrub away the oil. Clean the surface of the condenser tube cluster 4. Release the air 5. Discharge excess refrigerant 6. Check and repair the valve. How high is the exhaust temperature? 1. Exhaust valve plate and gasket are damaged. 2. Suction superheat is high. 3. Cylinder cooling is not good. 4. The liquid outlet of the separator is too small. 5. Large load. 1. Replace after inspection. 2. Excessive liquid supply to the expansion valve 3. Too thick frost on the evaporator 4. Ice on the evaporator 5. Insufficient cooling load 1. Reduce the opening of the suction valve 2. Adjust to make the return air superheated at 5-10℃ 3. Wash or sweep frost 4. Add salt 5. Adjust (2) Suction pressure is too high 1. Excessive refrigerant 2. Excessive heat load 3. Improper opening of expansion valve 4. Improper installation of temperature sensor package 5. Reduced compressor displacement 6. Oil return failure of oil separator 1. Release excess refrigerant 2. Adjust load 3. Adjust appropriately 4. Re-bandage 5. Inspection Check the valve plate, repair or replace it. 6. Check and repair or manual oil return. The suction pressure is too low. 1. There is frost. 2. Insufficient refrigerant. 3. Too much lubricating oil. 4. The evaporator is too frosted. 9. Insufficient opening of the cut-off door and liquid outlet valve on the liquid supply pipe 10. Solenoid valve failure 11. Blockage of the liquid pipe 12. Blockage of the filter 1. Remove the moisture in the system 2. Make up 3. Release part of it 4. Defrost 5. Clean and decontaminate 6. Adjust 7. Check and clean 8. Replace 9. Open fully 10, inspect and replace 11, clear 12, remove and clean Exhaust pressure is too low 1. The cooling of the condenser is too strong 2. The cooling process of the refrigerator 3. Insufficient or leaking refrigerant 4. Improper energy adjustment 1. Reduce the cooling water volume 2. Leak detection, replenish refrigerant (3) 3. Inspection or replacement 4. Inspection of compressor temperature stroke 5. Thermal expansion valve fails and opens too large 6. Solenoid valve fails, a large amount of refrigerant enters the evaporation pipe after shutdown and enters the compressor when starting up again 7. Too much refrigerant is injected into the system 8. The temperature sensing package of the thermal expansion valve is loose or not tied, causing the opening of the thermal expansion valve to increase 5. Close the liquid supply valve and inspect the thermal expansion valve 6. Inspect the solenoid Valve 7. Release excess refrigerant 8. Check the binding of the temperature sensing package. The compressor suddenly stops during operation. 1. The suction pressure is too low, lower than the low pressure limit of the pressure controller. 2. The exhaust pressure is too high, causing the high-pressure controller to operate and cut off the power. 3. The oil pressure is too low, and the oil pressure controller operates to cut off the power. 4. The motor is overloaded, and the thermal relay operates to cut off the power. 1. Check the cause. If the pipeline is clogged, clear the pipeline. If the system refrigerant is insufficient, replenish it. 2. Check the cooling water volume or cooling air volume of the condenser. 3. Check the oil delivery system pipeline and oil pump. 4. Check whether the power supply voltage is low or the cooling load is too large. Cold storage project refrigeration fault analysis (4) Troubleshooting. Compressor does not run (electrical reasons) 1. The power is out or the fuse is blown. The three-phase power is missing or the pressure relay is unbalanced. 2. The contact point of the starter is in poor contact. 3. The temperature controller is out of adjustment or has a water failure. 4. The pressure relay is not set properly. 1. Check the power supply and replace the fuse to eliminate the missing phase or imbalance. Check the pressure or repair the relay 2. Check the starter. Wipe the contacts with emery cloth 3. Check the temperature indication position. Check each component 4. Check each component and setting value of the pressure controller. The compressor stops after starting 1. Wrong connection of starting compensator and wrong connection of motor 1. Check the circuit ； 2. Ancient costume circuit. The compressor starts and stops frequently 1. The refrigeration system pressure is abnormal 2. The pressure controller is improperly adjusted 3. The refrigeration system pressure is too low 1. Check the high pressure and make the pressure normal again 2. Adjust and check whether there is fluorine leakage or blockage. The compressor does not run (mechanical reasons) or stops after starting 1 , stuck or holding the shaft 2. Abnormal oil pressure 3. The compressor stop valve, cooling water valve, liquid outlet valve, etc. are not opened 4. Improper adjustment of the temperature controller 5. Solenoid valve failure 1. Open the machine cover for inspection and repair 2. Check the oil circuit and oil supply 3. Check and open the valve (5) 4. Re-adjust 5. Check and repair the cylinder. There is a knocking sound 1. The piston engine part collides with the exhaust valve 2. The valve plate is damaged 3. The piston and piston ring are jammed 4. The piston ring is worn 5. Liquid shock 6. The valve screw is loose 7. Freezer Too much or impure oil 8. Foreign matter falls into 1. Increase the gap 2. Replace 3. Add lubricating oil or take it out for inspection 4. Replace 5. Find out the cause and eliminate it 6. Increase elasticity 7. Tighten 8. Clean the cylinder, change the oil, check and remove Cylinder wear 1. The piston clearance in the cylinder is too small 2. Foreign objects fall into the cylinder 3. There are impurities in the refrigeration oil 4. The refrigeration oil is impure and the model is wrong 5. The temperature is abnormal 6. The piston ring gap or lock size is wrong 7. Crankshaft Crank or connecting rod big end 8. Oil shock caused by oil splashing 1. Readjust according to regulations 2. Take it out after inspection 3. Replace 4. More abstract 5. Do not overheat, overtemperature 6. There is noise in the adjustment crankcase 1. The gap is too large (6) 2. Loose fit 3. Loose bolts or broken cotter pins, loose connecting rod nuts and poor bearing lubrication 4. The gap between the big end bearing bush of the connecting rod is too large 1. Check the gap between the big end bearing bush of the connecting rod and the crank, and between the crankshaft and the main bearing. and readjust or repair. Tighten loose parts. Replace cotter pin. Shaft seal oil leakage 1. The oil-resistant rubber ring is damaged, and the stone grinding also damages the contact surface. 1. Replace the shaft seal. The oil pipe is blocked, causing the cylinder to be short of oil and the piston is stuck. 3. The handle pin of the oil pump main gear inserted into the crankshaft is twisted, causing the oil system to cut off oil. 1. Replace new lubricating oil 2. Inspect the oil pump pipeline 3. Inspect and replace the oil pump main gear shaft. There is noise between the compressor and the motor coupling 1. The compressor and the Motor coupling coordination 2. Improper coordination of the coupling key and keyway 3. The elastic ring of the coupling is broken or damaged 4. The belt is too loose 5. The coupling inner hole and the shaft are loose 1. Reinstall according to the correct assembly requirements 2. Adjust the fit of the key and the keyway, replace the key 3. Tighten Elastic ring or replace with new parts 4. Adjust the tensioning belt 5. Adjust and tighten the coupling Various noises 1. Caused by compressor failure 1. Refer to the relevant chapters for increased power consumption 1. The internal parts of the compressor are too tight and 2. The thermal load increases 1. Overhaul 2. Remove part of the load (7) No oil pressure when starting the compressor 1. Oil pump transmission parts failed 2. Oil pump oil inlet blocked 3. Oil pressure gauge failed 4. No oil in the oil filter 1. Disassemble and repair 2. Remove dirt 3. Replace the oil pressure gauge 4. Remove the oil pump cover inspection pin and refuel the oil pressure controller to make compression The engine stops after starting 1. Abnormal oil pressure or lack of oil 1. Adjust the oil pressure, refuel, check the oil line to remove blockage. Oil pressure is too low 1. Insufficient oil volume 2. Adjustment failure 3. The filter is not clogged 4. The oil inlet is clogged 5. Operation under vacuum conditions 6. Oil pump wear 1. Supplement Oil 2. Check and adjust the oil pressure regulating valve 3. Remove and clean 4. Remove blockage 5. Adjust after inspection 6. Repair or replace Oil pressure drops quickly 1. Oil suction filter is clogged 2. Insufficient oil volume 3. Oil leakage 4. The crankcase oil is mixed with liquid refrigerant 5. (foaming) oil The pump sucks foamy oil 6. Oil emulsification and deterioration 1. Remove and clean 2. Make up 3. Repair the leak after inspection 4. Pump out the refrigerant 5. Change the oil and the oil pressure is too high 1. Improper oil pressure adjustment 2. Overfilling 3. The oil pipe is clogged 4. The oil pressure gauge is inaccurate 1. Readjust (relax the spring) 2. Drain oil 3. Check and clean (8) 4. Replacement oil temperature is too high 1. Exhaust temperature is too high 2. Oil cooling is not good 3. Compressor pressure difference is large 4. Assembly gap is small 1. Eliminate the cause of pressure increase 2. Increase cooling water volume 3. Adjust working conditions 4. Re-adjust motor overheating 1. Low voltage, resulting in large current 2. Insufficient refrigeration oil, resulting in large current 3. Overload operation 4. Air mixed in the refrigerant 5. Motor winding insulation damage 1. Check the reasons 2. Add oil 3. Do not overload 4. Exhaust air 5. Check and replace the motor Leakage and blockage fault analysis of refrigeration equipment, processing of refrigerant leakage blocks the capillary tube at the welding part of the half-blocked part (double coiled steel pipe) Phenomenon that occurs when measuring high and low pressures at the capillary welding joint of the evaporator. There is oil pollution at the leakage point. There is no oil pollution on the surface of the pipe. There is no oil pollution on the surface of the pipe. There is little or no condensation on the surface of the evaporator. There is no frost or condensation on the evaporator. There is very little frost and condensation on the evaporator. Refrigerant leakage can be detected with a leak detector. No response when tested with a leak detector. No response with a leak detector (9) The flow sound of the artesian well in the evaporator is interrupted or there is a weak flow sound. There is no flow sound of refrigerant at all in the evaporator. There is a flow sound of refrigerant in the evaporator. The balance pressure is lower than the normal pressure. The high and low pressure pressures are unbalanced. The high and low pressure pressures and the balance pressure are normal (after parking for 3 minutes). Phenomenon that appears in the low-voltage test. The current and power are normal (a small amount of leakage). The current and power do not decrease as the amount of leakage increases. The current and power are normal or decrease with the extension of the half-blocking time. Generally, the sound of the compressor is normal, but when the leakage is large, the sound is weak. The sound of the compressor is smaller than normal. The same as normal. The exhaust pipe temperature is high but decreases with the increase of leakage. The exhaust pipe temperature does not rise. The exhaust temperature is normal and increases with the half-blocked part. The protector and overheat protector operate the protector and overheat. The protector does not operate. The protector and superheater do not operate. Little or no gas is released after the process pipe is cut off. Gas flows out when the process pipe is cut off. Gas is released when the process pipe is cut off. Causes and countermeasures. During operation, the cooling water pump sucks air in. 1. The water level of the water tank below Low 2. The filter is clogged 1. Check the cause 2. The cleaning tower is polluted, and the circulating water is also polluted 1. Inhale the flue gas 2. Inhale the surrounding polluted air 3. The water treatment device is ineffective 1. Move the cooling tower or remove the flue gas (10) 2. Eliminate environmental pollution 3. Repair water treatment equipment cold storage common fault analysis and troubleshooting and troubleshooting (1) The exhaust pressure is too high 1. The cooling water volume of the water condenser is insufficient or the cooling air volume of the air-cooled condenser is insufficient. 2. The scale or oil on the surface of the condenser tube cluster is too thick, causing heat dissipation difficulties. 3. There is air in the refrigeration system. 4. Too much refrigerant is charged. 5. The exhaust pipe valve fails, causing the pressure to be too high. 1. Check whether the water valve is fully open, increase the water supply or check 2. Whether the motor voltage, speed, and transmission belt are loose. 3. Clean the scale and scrub away the oil. Clean the surface of the condenser tube cluster 4. Release the air 5. Discharge excess refrigerant 6. Check and repair the valve. How high is the exhaust temperature? 1. Exhaust valve plate and gasket are damaged. 2. Suction superheat is high. 3. Cylinder cooling is not good. 4. The liquid outlet of the separator is too small. 5. Large load. 1. Replace after inspection. 2. Excessive liquid supply to the expansion valve 3. Too thick frost on the evaporator 4. Ice on the evaporator 5. Insufficient cooling load 1. Reduce the opening of the suction valve 2. Adjust to make the return air superheated at 5-10℃ 3. Wash or sweep frost 4. Add salt 5. Adjust (2) Suction pressure is too high 1. Excessive refrigerant 2. Excessive heat load 3. Improper opening of expansion valve 4. Improper installation of temperature sensor package 5. Reduced compressor displacement 6. Oil return failure of oil separator 1. Release excess refrigerant 2. Adjust load 3. Adjust appropriately 4. Re-bandage 5. Inspection Check the valve plate, repair or replace it. 6. Check and repair or manual oil return. The suction pressure is too low. 1. There is frost. 2. Insufficient refrigerant. 3. Too much lubricating oil. 4. The evaporator is too frosted. 9. Insufficient opening of the cut-off door and liquid outlet valve on the liquid supply pipe 10. Solenoid valve failure 11. Blockage of the liquid pipe 12. Blockage of the filter 1. Remove the moisture in the system 2. Make up 3. Release part of it 4. Defrost 5. Clean and decontaminate 6. Adjust 7. Check and clean 8. Replace 9. Open fully 10, inspect and replace 11, clear 12, remove and clean Exhaust pressure is too low 1. The cooling of the condenser is too strong 2. The cooling process of the refrigerator 3. Insufficient or leaking refrigerant 4. Improper energy adjustment 1. Reduce the cooling water volume 2. Leak detection, replenish refrigerant (3) 3. Inspection or replacement 4. Inspection of compressor temperature stroke 5. Thermal expansion valve fails and opens too large 6. Solenoid valve fails, a large amount of refrigerant enters the evaporation pipe after shutdown and enters the compressor when starting up again 7. Too much refrigerant is injected into the system 8. The temperature sensing package of the thermal expansion valve is loose or not tied, causing the opening of the thermal expansion valve to increase 5. Close the liquid supply valve and inspect the thermal expansion valve 6. Inspect the solenoid Valve 7. Release excess refrigerant 8. Check the binding of the temperature sensing package. The compressor suddenly stops during operation. 1. The suction pressure is too low, lower than the low pressure limit of the pressure controller. 2. The exhaust pressure is too high, causing the high-pressure controller to operate and cut off the power. 3. The oil pressure is too low, and the oil pressure controller operates to cut off the power. 4. The motor is overloaded, and the thermal relay operates to cut off the power. 1. Check the cause. If the pipeline is clogged, clear the pipeline. If the system refrigerant is insufficient, replenish it. 2. Check the cooling water volume or cooling air volume of the condenser. 3. Check the oil delivery system pipeline and oil pump. 4. Check whether the power supply voltage is low or the cooling load is too large. Cold storage project refrigeration fault analysis (4) Troubleshooting. Compressor does not run (electrical reasons) 1. The power is out or the fuse is blown. The three-phase power is missing or the pressure relay is unbalanced. 2. The contact point of the starter is in poor contact. 3. The temperature controller is out of adjustment or has a water failure. 4. The pressure relay is not set properly. 1. Check the power supply and replace the fuse to eliminate the missing phase or imbalance. Check the pressure or repair the relay 2. Check the starter. Wipe the contacts with emery cloth 3. Check the temperature indication position. Check each component 4. Check each component and setting value of the pressure controller. The compressor stops after starting 1. Wrong connection of starting compensator and wrong connection of motor 1. Check the circuit ； 2. Ancient costume circuit. The compressor starts and stops frequently 1. The refrigeration system pressure is abnormal 2. The pressure controller is improperly adjusted 3. The refrigeration system pressure is too low 1. Check the high pressure and make the pressure normal again 2. Adjust and check whether there is fluorine leakage or blockage. The compressor does not run (mechanical reasons) or stops after starting 1 , stuck or holding the shaft 2. Abnormal oil pressure 3. The compressor stop valve, cooling water valve, liquid outlet valve, etc. are not opened 4. Improper adjustment of the temperature controller 5. Solenoid valve failure 1. Open the machine cover for inspection and repair 2. Check the oil circuit and oil supply 3. Check and open the valve (5) 4. Re-adjust 5. Check and repair the cylinder. There is a knocking sound 1. The piston engine part collides with the exhaust valve 2. The valve plate is damaged 3. The piston and piston ring are jammed 4. The piston ring is worn 5. Liquid shock 6. The valve screw is loose 7. Freezer Too much or impure oil 8. Foreign matter falls into 1. Increase the gap 2. Replace 3. Add lubricating oil or take it out for inspection 4. Replace 5. Find out the cause and eliminate it 6. Increase elasticity 7. Tighten 8. Clean the cylinder, change the oil, check and remove Cylinder wear 1. The piston clearance in the cylinder is too small 2. Foreign objects fall into the cylinder 3. There are impurities in the refrigeration oil 4. The refrigeration oil is impure and the model is wrong 5. The temperature is abnormal 6. The piston ring gap or lock size is wrong 7. Crankshaft Crank or connecting rod big end 8. Oil shock caused by oil splashing 1. Readjust according to regulations 2. Take it out after inspection 3. Replace 4. More abstract 5. Do not overheat, overtemperature 6. There is noise in the adjustment crankcase 1. The gap is too large (6) 2. Loose fit 3. Loose bolts or broken cotter pins, loose connecting rod nuts and poor bearing lubrication 4. The gap between the big end bearing bush of the connecting rod is too large 1. Check the gap between the big end bearing bush of the connecting rod and the crank, and between the crankshaft and the main bearing. and readjust or repair. Tighten loose parts. Replace cotter pin. Shaft seal oil leakage 1. The oil-resistant rubber ring is damaged, and the stone grinding also damages the contact surface. 1. Replace the shaft seal. The oil pipe is blocked, causing the cylinder to be short of oil and the piston is stuck. 3. The handle pin of the oil pump main gear inserted into the crankshaft is twisted, causing the oil system to cut off oil. 1. Replace new lubricating oil 2. Inspect the oil pump pipeline 3. Inspect and replace the oil pump main gear shaft. There is noise between the compressor and the motor coupling 1. The compressor and the Motor coupling coordination 2. Improper coordination of the coupling key and keyway 3. The elastic ring of the coupling is broken or damaged 4. The belt is too loose 5. The coupling inner hole and the shaft are loose 1. Reinstall according to the correct assembly requirements 2. Adjust the fit of the key and the keyway, replace the key 3. Tighten Elastic ring or replace with new parts 4. Adjust the tensioning belt 5. Adjust and tighten the coupling Various noises 1. Caused by compressor failure 1. Refer to the relevant chapters for increased power consumption 1. The internal parts of the compressor are too tight and 2. The thermal load increases 1. Overhaul 2. Remove part of the load (7) No oil pressure when starting the compressor 1. Oil pump transmission parts failed 2. Oil pump oil inlet blocked 3. Oil pressure gauge failed 4. No oil in the oil filter 1. Disassemble and repair 2. Remove dirt 3. Replace the oil pressure gauge 4. Remove the oil pump cover inspection pin and refuel the oil pressure controller to make compression The engine stops after starting 1. Abnormal oil pressure or lack of oil 1. Adjust the oil pressure, refuel, check the oil line to remove blockage. Oil pressure is too low 1. Insufficient oil volume 2. Adjustment failure 3. The filter is not clogged 4. The oil inlet is clogged 5. Operation under vacuum conditions 6. Oil pump wear 1. Supplement Oil 2. Check and adjust the oil pressure regulating valve 3. Remove and clean 4. Remove blockage 5. Adjust after inspection 6. Repair or replace Oil pressure drops quickly 1. Oil suction filter is clogged 2. Insufficient oil 3. Oil leakage 4. The oil in the crankcase is mixed with liquid refrigerant 5. (foaming) oil The pump sucks foamy oil 6. Oil emulsification and deterioration 1. Remove and clean 2. Make up 3. Repair the leak after inspection 4. Pump out the refrigerant 5. Change the oil and the oil pressure is too high 1. Improper oil pressure adjustment 2. Overfilling 3. The oil pipe is clogged 4. The oil pressure gauge is inaccurate 1. Readjust (relax the spring) 2. Drain oil 3. Check and clean (8) 4. Replacement oil temperature is too high 1. Exhaust temperature is too high 2. Oil cooling is not good 3. Compressor pressure difference is large 4. Assembly gap is small 1. Eliminate the cause of pressure increase 2. Increase cooling water volume 3. Adjust working conditions 4. Re-adjust motor overheating 1. Low voltage, resulting in large current 2. Insufficient refrigeration oil, resulting in large current 3. Overload operation 4. Air mixed in the refrigerant 5. Motor winding insulation damage 1. Check the reasons 2. Add oil 3. Do not overload 4. Exhaust air 5. Check and replace the motor Leakage and blockage fault analysis of refrigeration equipment, processing of refrigerant leakage blocks the capillary tube at the welding part of the half-blocked part (double coiled steel pipe) Phenomenon that occurs when measuring high and low pressures at the capillary welding joint of the evaporator. There is oil pollution at the leakage point. There is no oil pollution on the surface of the pipe. There is no oil pollution on the surface of the pipe. There is little or no condensation on the surface of the evaporator. There is no frost or condensation on the evaporator. There is very little frost and condensation on the evaporator. Refrigerant leakage can be detected with a leak detector. No response when tested with a leak detector. No response with a leak detector (9) The flow sound of the artesian well in the evaporator is interrupted or there is a weak flow sound. There is no flow sound of refrigerant at all in the evaporator. There is a flow sound of refrigerant in the evaporator. The balance pressure is lower than the normal pressure. The high and low pressure pressures are unbalanced. The high and low pressure pressures and the balance pressure are normal (after parking for 3 minutes). Phenomenon that appears in the low-voltage test. The current and power are normal (a small amount of leakage). The current and power do not decrease as the amount of leakage increases. The current and power are normal or decrease with the extension of the half-blocking time. Generally, the sound of the compressor is normal, but when the leakage is large, the sound is weak. The sound of the compressor is smaller than normal. The same as normal. The exhaust pipe temperature is high but decreases with the increase of leakage. The exhaust pipe temperature does not rise. The exhaust temperature is normal and increases with the half-blocked part. The protector and overheat protector operate the protector and overheat. The protector does not operate. The protector and superheater do not operate. Little or no gas is released after the process pipe is cut off. Gas flows out when the process pipe is cut off. Gas is released when the process pipe is cut off. Causes and countermeasures. During operation, the cooling water pump sucks air in. 1. The water level of the water tank below Low 2. The filter is clogged 1. Check the cause 2. The cleaning tower is polluted, and the circulating water is also polluted 1. Inhale the flue gas 2. Inhale the surrounding polluted air 3. The water treatment device is ineffective 1. Move the cooling tower or remove the flue gas (10) 2. Eliminate environmental pollution 3. Repair water treatment equipment combination library maintenance knowledge and troubleshooting methods 1. There is no power on the distribution box or the display screen does not display. Please check whether the special gate of the cold storage is malfunctioning. (Check the power supply and distribution box) 2. The cold storage is not cooling or the cooling effect is poor. Check whether the condenser of the refrigerator is dirty. Check whether there is too much frost on the evaporator in the library. Check for refrigerant leakage (coat the pipe connections with soapy water, if bubbles appear, it indicates refrigerant leakage). And ask professionals to replenish the refrigerant and deal with leaks. Check whether the cold storage door seal is intact and remove it. Check whether the refrigerator in the cold storage is working. Check whether the parameter settings of the computer controller of the cold storage are correct and readjust them. Check whether the cold storage controller is malfunctioning and replace it. Check whether there are enough gaps between items stacked in the warehouse and clear them. 3. If there is abnormal noise when the machine is running, please stop it and check whether it is caused by vibration or mechanical failure. There is abnormal noise in the distribution box. This is the sound emitted by the AC contactor. It is due to the partial inflexibility of the moving parts of the contactor. Please turn off the power and press the magnet of the contactor back and forth to eliminate the noise. 4. The refrigerator starts frequently or does not start for a long time, or does not stop when it is turned on for a long time, or it stops when the storage temperature is not reached. A. Check whether there is dirt on the condenser. Poor heat dissipation will cause the condensation pressure of the refrigerator to be too high. In order to protect the compressor, the machine will stop running under the action of the pressure controller. After the heat dissipation is good, press the black reset button on the pressure controller and the machine will automatically resume operation. B. The parameter setting of the controller is wrong, just reset it. C. Refrigeration is not good, please refer to fault 2. D. Temperature control failure. E. Electrical appliances are damaged. 5. The cold storage distribution box did not respond after closing, but the three-phase power was normal. Please check the neutral line to see if there is 220V voltage. The components of the cold storage (various valves, controllers) have been set, and there are no parts that the user needs to adjust. 6. The lighting in the warehouse is not on. Please check whether the switch is malfunctioning and whether the bulb is damaged. Cut off the power supply during inspection, and pay attention to the waterproofness of the lamp when installing the lampshade. 7. When the ambient temperature is too high, after the refrigerator has been running for a period of time, the storage temperature does not reach the set value and the refrigerator stops early. This is due to the increase in ambient temperature causing the condensation pressure of the refrigerator to be too high. In order to protect the compressor, the machine stops running under the action of the pressure controller. After the heat dissipation is good, press the black reset button on the pressure controller and the machine will automatically resume operation. And check whether the water condenser dissipates heat well. Do not adjust the setting value on the pressure controller arbitrarily, otherwise the pressure controller will not be able to protect the refrigerator. 8. The cold storage door is not closed tightly. Please adjust the hinges on the door and the distance between the door lock and the storage body. (The adjustment degree should not be too large, otherwise the door switch will be very inflexible. ) This post was last edited by edc1233 on 2008-8-2 21:05 ]