The problem of frosting in evaporator for cold room storage
For cold room storage, it is common that evaporator have ice while worked for a period of time. And, frosting evenly in evaporator is normal. But, if the frost is uneven, the refrigeration unit is meeting some problem. Four unnormal frosting as below:
Problem 1: The inlet part of the evaporator is with frost, but without in the outlet part.
The reason is that not enough liquid refrigerant is pump to evaporator. Liquid refrigerant is already evaporated completely before flow out the evaporator.
Problem 2: The outlet part of the evaporator is with frost, but without in the inlet part.
The reason is that too much liquid refrigerant pump to evaporator.
Problem 3: Top part of the evaporator is with frost, bottom part without frost.
Too much lubricating oil in the bottom of evaporator. Liquid refrigerant can not evaporate well in the bottom.
Problem 4: The frost is covered in the evaporator but uneven.
The reason is that evaporator full with oil and the efficiency of exchange heat is not good.