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REASON FOR REFRIGERATION PLANT COMPRESSOR SUCTION SIDE FROSTING OR SWEATING?

Actually, frost on the suction line only indicates that at the location where the frost is present, the suction line piping is below the dew point temperature of the surrounding ambient air. That’s it. It is neither an indication of a properly operating system nor a system defect.

Reason for refrigeration plant compressor suction line frosting or sweating?


Actually, frost on the suction line only indicates that at the location where the frost is present, thesuction line piping is below the dew point temperature of the surrounding ambient air. That’s it. It is neither an indication of a properly operating system nor a system defect. Although it is normal for many refrigeration systems to have frost on the suction line, it is not a very accurate indication of a properly operating system. The measurement must be done for the refrigerant’s superheat value, when analyzing the operation of a system. While troubleshooting a system, normally measure the refrigerant superheat value at two locations along the suction line.
Reason for refrigeration plant compressor suction line frosting or sweating?
The first location is at the outlet of the evaporator, typically referred to as the “evaporator’s superheat.” Measuring the evaporator’s superheat value is an important part of analyzing a system’s performance.If a lower than normal value is measured, too much refrigerant is entering the evaporator for the present heat load.  As a rule of thumb, many medium temperature systems will generally have a superheat of 8 to 10 degrees and many low temperature applications of 4 to 6 degrees or always refer to the manufacturer’s specications.
Reason for refrigeration plant compressor suction line frosting or sweating?


The second typical location to measure the refrigerant’s superheat is at the inlet of the compressor, commonly referred to as the system’s “total superheat.”  This can be an important measurement for compressors as it ensures that the returning refrigerant will not cause damage to the compressor. A saturated refrigerant (0° superheat) or excessively high superheat value may cause damage to a compressor. A saturated refrigerant at this location indicates that some amount of liquid refrigerant is returning to the compressor. Liquid refrigerant returning to a compressor can damage it in one of two ways:  It can mix with the compressor’s lubricating oil. As the liquid refrigerant comes in contact with the bearing surfaces it will wash away the oil film and cause wearing of the bearings.Depending on the percentage of liquid refrigerant to oil, the bearing Wear could be mild to severe. If a sucient amount of liquid returns to the compressor, it may be possible for liquid to enter the cylinder of the compressor and cause further damage to the compressor as it attempts to compress a liquid.
Reason for refrigeration plant compressor suction line frosting or sweating?
While troubleshooting refrigeration systems, we should measure both the temperature and pressure and calculate the refrigerant’s superheat value to help determine the true cause of a system problem.  Expansion valve oversized or passing excess refrigerant.[Replace it with smaller valve.]  Exapnsion valve stuck open. [Clean valve of foreign particles.] Evaporator fan not working. [Check for reason.] Iceing on evaporator coils. [Defrost cycle] Overcharge of refrigerant. [Correct charge]
Reason for refrigeration plant compressor suction line frosting or sweating?


Reason for refrigeration plant compressor suction line frosting or sweating?

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