The reason for the evaporator frost in a nutshell is: low evaporating temperature & insufficient heat exchange of the evaporator (one or the other is indispensable)! Detailed analysis down, we can analyze from the following 8 reasons.
01), insufficient air supply, including the return air duct blockage, filter blockage, fin gap blockage, fan does not rotate or speed reduction, resulting in insufficient heat transfer, evaporative pressure reduction, evaporative temperature reduction.
02), the heat exchanger itself, heat exchanger common use, heat transfer performance decline, so that the evaporative pressure is reduced.
03), the external temperature is too low, civil refrigeration is generally not less than 20 ℃, refrigeration in a low-temperature environment will cause insufficient heat transfer, low evaporative pressure;
04), the expansion valve is gambling plug or control the opening of the pulse motor system damage, long-term operation of the system, some debris will be blocked in the mouth of the expansion valve so that it can not work properly, reducing the refrigerant flow, so that the evaporative pressure is reduced, the opening of the control is out of order will also cause a reduction in the flow rate, the pressure is reduced.
05), secondary throttling, pipe bending or clogging of debris inside the evaporator, resulting in secondary throttling, so that after the second throttling of the part of the pressure reduction, temperature reduction.
106), the system is poorly matched, to be precise, the evaporator is small or the compressor condition is too high, in this case, even if the evaporator performance is fully played, due to the compressor condition is too high will cause suction pressure is low, the evaporating temperature drops;
07), lack of refrigerant, low evaporating pressure, low evaporating temperature.
08), too much refrigerant, many people think that too much refrigerant evaporating pressure rise will not produce frost, but too much refrigerant after the excess refrigerant is basically in liquid form in the condenser after the section to the expansion valve before the pipeline, this time the system cycle slows down, the liquid subcooling increases, the expansion valve opens up to reduce evaporative temperature, I have seen too much refrigerant back to the gas pipe temperature is negative.
Post time: Nov-08-2024
