Compressor frosting is very serious what are the reasons? - Zhejiang BingEr New Type Refrigerant Co.,Ltd.

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Compressor frosting is very serious what are the reasons?
date： 2020-09-28　 hits：730　
FROSTING is a common phenomenon in therefrigeration system of the compressor return port of the cold storage.Generally, the system problem will not be formed immediately, and the slightfrosting generally need not be dealt with. If Frost phenomenon is more serious,so need to make clear frost reason above all.
FROSTING on the return port of thecompressor
Return Port frosting that compressorreturn temperature is too low, then what will lead to compressor return gastemperature is too low?
With the same mass of refrigerant, thetemperature will behave differently if the volume and pressure are changed. Ifthe return air temperature of the compressor is low, the return air pressure isgenerally low and the refrigerant volume is high at the same time, therefrigerant flowing through the evaporator can not fully absorb the heatrequired to expand to a predetermined pressure-temperature value.
There are two causes of this problem:
1, throttle liquid refrigerant supply isnormal, but the evaporator can not normal heat absorption;
2, the evaporator works properly, but thethrottle valve refrigerant supply is too much, that is, too much refrigerantflow, we usually understand that too much refrigerant.
Due to less fluoride caused by thecompressor return frost
1,Refrigerant traffic is extremely low.Too little expansion of refrigerant will not make use of all the evaporatorarea, only in the evaporator local formation of low temperature, part of theregion as a result of less refrigerant and rapid expansion of low localtemperature, evaporator frosting phenomenon.
After partial frosting, due to theformation of a heat-insulating layer on the surface of the evaporator and thelow heat transfer in this area, the expansion of the refrigerant is transferredto other areas, and gradually the whole evaporator frosting or icing occurs,and the whole evaporator forms a heat-insulating layer, then the expansion willspread to the compressor return pipe cause compressor return air frosting.


2,Due to the low amount of refrigerant.Low evaporating pressure leads to low evaporating temperature, and willgradually lead to condensation of the evaporator to form a heat insulationlayer, and the expansion point to the compressor back to cause the compressorback gas frosting.
The above two points will be in thecompressor return air frosting before the performance of evaporator frosting.
In fact, in most cases for the phenomenonof Frost, as long as the regulation of hot air bypass valve on the line. Thespecific method: is to open the hot air bypass valve rear end cover, and thenuse No. 8 hexagon wrench, clockwise rotation inside the adjustment nut,adjustment process is not too fast, usually turn about half a circle to pausefor a moment, let the system run for a period of time to see if the frostingsituation before deciding whether to continue to adjust. When the operation isstable and the frost phenomenon of the compressor disappears, then screw theend cover tightly.
FROSTING ON CYLINDER HEAD (crankcase insevere cases)
FROSTING OF CYLINDER head is due to a largenumber of wet steam or refrigerant inhalation compressor caused. The mainreasons for this are:


1, the thermal expansion valve opened toolarge, temperature sensor package installation error or fixed loose, so that thetemperature is too high to feel the valve core opened abnormally.
The thermal expansion valve is adirect-acting proportional regulator, which uses the superheat at the outlet ofthe evaporator as a feedback signal and compares it with a given superheatvalue to produce a deviation signal to regulate the flow of refrigerant intothe evaporator, it integrates a transmitter, a regulator and an actuator.
Thermal expansion valve according to the balanceof different ways can be divided into: Internal Balance and external balancethermal expansion valve two kinds.


Thermal expansion valve open too large,temperature sensor package installation error or fixed loose, so that thetemperature is too high and abnormal open Spool, so that a large number of wetsteam into the compressor leading to frosting cylinder head.
If the outlet overheating degree of theevaporator is too large, the rear overheating section of the evaporator will betoo long, and the cooling capacity will be significantly reduced. It is generallybelieved that the expansion valve should be adjusted to the outlet of theevaporator to work at 3 °C ~ 8 °C.
2, the supply solenoid valve leakage orshutdown expansion valve closed loosely. A large amount of refrigerant liquidhas accumulated in the evaporator before start-up. This situation is also easyto cause the compressor fluid hit!

3,Too muchrefrigerant in the system. The liquid level in the condenser is higher, thecondensation heat transfer area is reduced, the condensation pressure is increased,that is, the pressure before the expansion valve is increased, the amount ofrefrigerant flowing into the evaporator is increased, the liquid refrigerantcan not completely evaporate in the evaporator, so the compressor inhalation ofwet steam, cylinder head cold or even frosting, and may cause "liquidshock" , while the evaporation pressure will also be high.
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