Fault phenomenon of improper adjustment of the thermal expansion valve
1. The opening degree is too small
If the opening degree of the thermal expansion valve is too small, it will cause insufficient liquid supply, so that there is not enough Freon to evaporate in the evaporator, and the refrigerant has evaporated on the way to the evaporator tube. There is no liquid refrigerant in the evaporator tube after this, and only the steam is overheated.
At the same time, the outlet pressure of the expansion valve is too low, and the corresponding evaporation pressure and temperature are also too low. The evaporation speed slows down, the cooling capacity per unit volume (time) decreases, and the cooling efficiency decreases.
Therefore, a considerable part of the evaporator fails to fully exert its efficiency, resulting in insufficient cooling capacity and reducing the cooling effect of the air conditioner. The compressor of the dedicated air conditioner in the computer room mostly uses the steam returned from the evaporator to cool the compressor. If the thermal expansion valve is not opened enough, the steam superheat will be too large, the cooling effect on the compressor will be reduced, the exhaust temperature of the compressor will increase, the lubricating oil will become thinner, the lubrication quality will decrease, and the working environment of the compressor will deteriorate, which will seriously affect the working life of the compressor.
2. Too much opening
If the thermal expansion valve is opened too much, the flow rate of refrigerant passing through will be too large, that is, the amount of liquid supplied by the thermal expansion valve to the evaporator is greater than the load of the evaporator, causing excessive evaporation of liquid refrigerant, which will cause some liquid refrigerant to not have time to evaporate in the evaporator and be sucked into the compressor together with the gaseous refrigerant, causing the wet stroke (liquid hammer) of the compressor, making the compressor unable to work normally, causing a series of bad working conditions, and even accidents such as cylinder impact and damage to the compressor.
At the same time, if the thermal expansion valve is opened too much, the corresponding evaporation pressure and temperature of the refrigerant entering the evaporator will also be too high, the cooling capacity will decrease, the power consumption of the compressor will increase, and the power consumption will increase.
Since the refrigeration power of the new compressor is not equipped with the system, the adjustment pressure of the expansion valve is always lower than normal, indicating that the compressor power is too large, resulting in large suction volume, small evaporation area, and contradictory operating conditions. If the expansion valve is opened again, the liquid cannot boil and evaporate, and the over-humidified gas will be sucked in, causing the compressor to frost.
