Problems with frosting behind expansion valves in environmental chambers
1. Someone will first consider whether the expansion valve is blocked or the opening of the expansion valve is too small.
2. Still some people will consider whether the fan is faulty.
3. Of course, some people will analyze from the frosting direction.
Of course, this is only part of the reason why a small number of friends think.
Summarize the direction of frost on the refrigeration system.
As we all know, the direction of frost formation is divided, and there are mainly the following two:
1. Start with the compressor air return to the evaporator in the direction of frost.
2. The expansion valve is frosted in the direction of the evaporator.
An analysis of the difference between these two types of frosting is caused by the opposite reason, so when friends eliminate problems, “we cannot see only the expansion valve, the evaporator, and the return pipe frost, and we must distinguish the frosted direction."
The air outlet begins to frost and the air outlet starts to be frosted, mainly from the following two aspects:
1. The reason for the refrigerant is that more refrigerant enters the evaporator, resulting in incomplete evaporation, so the return air pipe is still evaporating, absorbing the heat of the suction pipe, so the return pipe first frosts.
Causes are: 1, excessive refrigerant; 2, expansion valve opening is too large;
2. Evaporator The evaporator can't absorb heat normally, or the cooling capacity produced by the evaporator can't be taken away, it will cause the evaporation to be incomplete. The refrigerant will continue to evaporate and absorb heat in the return air pipe, causing the return air pipe to frost.
The appearance is that the liquid return temperature and pressure are normal or slightly lower, and the compressor gradually returns to the direction of evaporator frost from the air return port. After a long period of time, all the ice is formed from the compressor air return port to the evaporator and the throttle valve to the evaporator section. Finally, the low pressure appeared.
The causes are:
1, take a look at the air filter is clean;
2, see the fan speed is normal;
3, whether the evaporator is clean;
4. Does the air supply system block?
5, the belt is too loose.
2. Expansion valve starts frosting behind the expansion valve, mainly from the following three points:
1, less refrigerant (leakage)
The liquid return temperature of the condenser is high but the pressure is not high, and the throttle gradually begins to frost in the direction of the evaporator.
2. The opening degree of the expansion valve is too small. The temperature and pressure of the condenser return fluid are normal or slightly lower. The throttle valve is gradually frosted in the direction of the evaporator.
3, to check the liquid crystal lens to see the situation of the refrigerant, blistering is serious, may be a system leak; the liquid refrigerant in the liquid mirror does not bubbling or very little bubbling, may be too small expansion valve, or plug, generally in the plug There will be a large temperature difference between before and after.
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