Troubleshooting of High Exhaust Temperature of Cold Storage Compressor | Exhaust Overtemperature, Cooling, and Protection Logic
The exhaust temperature reflects the internal working conditions of the compressor. If the exhaust temperature continues to be high, it will accelerate the cracking, carbon deposition, and valve plate aging of the refrigeration oil. The cracking rate of POE oil will significantly accelerate when it exceeds 120 ℃.
Normal exhaust temperature range for R404A low-temperature piston unit: 70-95 ℃; When the exhaust temperature exceeds 110 ℃ and enters the high-risk zone, many units are equipped with 120 ℃ exhaust high temperature protection shutdown.
The five major causes of high exhaust temperature are: excessive superheat of the return air, insufficient refrigerant, high condensation pressure, insufficient cooling, and high compression ratio (low evaporation pressure).
The Xiteluo unit is equipped with an exhaust temperature sensor, and the exhaust high temperature protection belongs to slow protection, giving the system buffer time, which is different from the instantaneous shutdown of high-pressure protection.
The most common cause of high exhaust temperature on site is that the expansion valve is too small and the superheat of the return air is too high; The evaporator is short of liquid and sucks in high-temperature gaseous refrigerant, causing the temperature to soar after compression.
Many maintenance personnel only focus on the high pressure and ignore the exhaust temperature. The high pressure is normal, but the superheat of the return air is too high, and the exhaust still exceeds the standard. The oil slowly carbonizes, and the valve plate becomes clogged and fails.
The exhaust temperature control of screw compressors is more stringent, and some models are equipped with oil injection cooling. Insufficient oil injection will directly cause high exhaust temperature; Blockage of the fuel injection cooling oil circuit filter is a common fault.
For high-altitude foreign trade projects, the compression ratio increases at the same evaporation and condensation temperature, resulting in naturally higher exhaust temperatures. During the selection stage, a larger heat exchange margin is reserved to enlarge the condenser.
Exhaust high-temperature treatment steps: first measure the superheat of the return gas, then check the condensation pressure and verify the refrigerant quantity; Do not directly lower the exhaust protection threshold and forcefully operate.
After carbonization of refrigeration oil, carbon powder adheres to valve plates and motor windings, causing insulation degradation and poor sealing of valve plates, which is irreversible damage and requires disassembly and cleaning.
Implant 10 popular search keywords: compressor exhaust temperature, compressor exhaust high temperature protection, R404A compressor, evaporator superheat, thermal expansion valve, screw refrigeration compressor, POE refrigeration oil, semi closed piston compressor, compression condensing unit, refrigeration maintenance company
FAQ
1. What is the normal exhaust temperature of R404A low-temperature piston engine? 70-95 ℃.
What is the typical shutdown temperature for exhaust high-temperature protection? Most settings are around 120 ℃.
What are the consequences of excessive overheating of the return air? The exhaust temperature continues to rise.
What will happen to high-temperature exhaust refrigerant oil? High temperature cracking, carbon deposition and carbonization.
5. Common methods for controlling exhaust temperature in screw machines? Spray cooling.
6. Will high pressure cause high exhaust temperature? Yes, excessive overheating of the return air will occur.
Can the protection value be directly lowered to continue running when the exhaust temperature is high? Strictly prohibited, it may cause permanent damage to the compressor
