The failure of the low temperature circulation device frosting is mainly because the compressor return air temperature is too low, which may be that the throttle valve liquid refrigerant supply is in a normal state in the low temperature circulation device, but the low temperature circulation device evaporator cannot normally absorb the heat supply refrigerant expansion; It may also be because the evaporator is in a normal working state but the refrigerant supply throttle valve is too large, causing the low pressure to cause the compressor return air temperature to be too low.
After a little frosting, because the heat insulation layer on the surface of the evaporator has low heat, the refrigerant will transfer to other areas after expansion, causing frosting in the evaporator of the low-temperature circulation device, which will cause the low-temperature circulation device to evaporate. The insulation layer appears to expand to the compressor return pipe causing the compressor to return to air and frost. When the low temperature circulation device has less refrigerant, it is found that the low pressure of the evaporator causes the evaporation temperature to be low, so that the expansion point of the frost layer on the surface of the evaporator is transferred to the compressor return air to cause frosting of the compressor.
In the face of such a phenomenon of frosting of the compressor, Wuxi Yuze suggested that if the system has a heat exchanger bypass valve, then it is only necessary to adjust the hot gas bypass valve. The low temperature circulation device is running this process.
Open the rear end cover of the hot gas bypass valve of the low temperature circulation device, and then use the hex wrench of the toolbox to turn the adjusting nut clockwise. The adjustment process of the defrosting process should not be too fast. Generally, the half cycle is suspended. Let the low temperature circulation device refrigeration system run for a period of time and then look at the frost condition before deciding whether to continue to adjust. Wait for the low-temperature cycle device to run stably, and then tighten the end cap after the compressor frosting disappears. The defrosting process of the low-temperature cycle device can be solved!
For models below 15 cubic meters, since there is no hot gas bypass valve, if the frosting phenomenon is serious, the take-off pressure of the pressure switch of the condensing fan can be appropriately adjusted. specific method:
First find the pressure switch, remove the adjustment nut of the pressure switch to fix the small piece, then use a Phillips screwdriver to rotate clockwise, the whole adjustment also needs to be carried out slowly, adjust the half turn to see the situation and then decide whether it needs adjustment.
The low-temperature circulation device needs to pay attention when performing defrosting. When the model size of the equipment is very different, pay attention to the difference in details when repairing.