Compressor overheat protection is to protect the compressor motor from being burned, when the motor temperature or compressor temperature exceeds a certain value, through some built-in or external protection devices to disconnect the compressor power supply, so as to protect the compressor. The refrigeration compressor absorbs low temperature and low pressure gaseous refrigerant from the system directly into the shell cavity of the compressor, and the inhaled refrigerant cools the motor first, and then compresses. Therefore, the size of the superheat of the inhaled refrigerant vapor is an important reason for whether the compressor is overheating.

1. Lack of refrigerant

The lack of refrigerant will lead to a reduction in the amount of refrigerant provided to the evaporator, resulting in high evaporation temperature, high refrigerant vapor temperature inhaled by the compressor, that is, high superheat, resulting in overheating of the compressor motor coil, causing overheating protection.

In hot summer, the ambient temperature is too high, when the lack of refrigerant in the system is not much, it is difficult to judge by the current of the compressor and the pressure measured by the system, but it is easy to overfill. In this case, you can measure the temperature of the compressor exhaust pipe. If the temperature is normal, it is about 20 ° C higher than the saturation temperature corresponding to the exhaust pressure. If it is lower than the temperature, it indicates that there is too much refrigerant; if it is higher than the temperature, it indicates that there is insufficient refrigerant.

Second, the evaporator dirty/condenser dirty

If the heat dissipation of the evaporator is very bad, it can be equivalent to the case that the internal fan does not turn, we all know that at this time the refrigerant evaporation effect in the evaporator is very poor, then the compressor should be inhaled by the gas-liquid mixture of refrigerant, in this case the compressor return gas should be frosted, so the evaporator heat dissipation is very bad, can not be used as the cause of the compressor overheating. However, when the heat dissipation of the evaporator is not very good, it will lead to the insufficient refrigeration dose of the compressor, that is, the refrigerant circulation is not enough, which is completely likely to lead to the overheating protection of the compressor. Therefore, it is recommended to clean not only the condenser but also the evaporator when the compressor overheat protection failure is repaired.

Third, low voltage

Practice has proved that when the power supply voltage drops below 190V, the system pressure will not go up and the low pressure will not come down. This is equivalent to the compressor gas channeling, resulting in the compressor suction refrigerant gas specific volume becomes larger, causing the compressor return gas superheat increase leading to thermal protection.

Four, the compressor itself

Four-way valve gas: the compressor is cooled by low temperature return gas, if the four-way valve gas, then the compressor suction is not cold but hot gas, the compressor not only can not be cooled, but also "adding oil to the fire" heat heating, not hot protection is strange! The press is colluded, the refrigeration is not good, the high pressure can not play up is not heat protection!

Lack of oil: compressor lack of oil is indeed heat protection, lack of oil will lead to poor lubrication of mechanical parts, this problem we have also done a detailed analysis before the public refrigeration encyclopedia.

Capacitors: bad capacitors cause thermal protection of the press, which is not a rare thing, and sometimes the capacitors bought back on the market are not reliable, this kind of thing is not without.

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Declaration: The content and template of this article are organized from the network, and the copyright belongs to the original author; If there is infringement, please inform in time and contact to delete.