What are the symptoms of an excessively open expansion valve?

[DelParker]

An excessively open expansion valve is manifested by higher-than-normal temperature at the air conditioning vents inside the vehicle. The low-pressure side pressure is elevated, where the normal high pressure should be between 1-20 kg, and the low pressure between 2-3 kg. Elevated suction pressure leads to an increase in suction temperature, which in turn raises the discharge temperature. Excessively high discharge temperature poses significant risks to compressor lubricating oil and coil insulation, ultimately damaging the compressor. Consequences of an oversized thermal expansion valve configuration: 1. Compressor damage: An excessively open thermal expansion valve, meaning the liquid refrigerant supply to the evaporator exceeds the evaporator load, results in incomplete refrigerant evaporation in the evaporator. This causes liquid refrigerant to enter the compressor along with gaseous refrigerant, leading to wet compression or even cylinder impact accidents, damaging the compressor. 2. Increased power consumption: An excessively open thermal expansion valve raises the evaporation temperature, reduces cooling capacity, increases compressor power consumption, and consequently raises electricity usage.