If fluoride is added too much, the general air conditioner will not cool well or at all, but some air conditioners with special capacity will have other situations. Otherwise, some models of Changhong air conditioner will have overcurrent protection due to excessive fluoride addition.

When it is determined that there is a lack of refrigerant oil in the pipeline of the refrigeration system, the refrigerant in the pipeline should be recovered to the pipeline of the outdoor unit, and an appropriate amount of new refrigerant oil should be added from the needle valve of the low-pressure cut-off valve, and then vacuum is applied to release the refrigerant. If the original refrigeration oil in the system pipeline is severely carbonized, the inside of the air conditioning system pipeline should be thoroughly cleaned.

The requirements for refrigeration oil are as follows:

The freezing point of (1) refrigeration oil when it is cooled to the temperature where it stops flowing under experimental conditions is called freezing point. The freezing point of refrigerating machine oil used in refrigeration equipment should be as low as possible (such as R22 compressor, refrigerating machine oil should be below -55℃), otherwise it will affect the flow of refrigerant, increase the flow resistance and lead to poor heat transfer effect.

(2) The viscosity of refrigeration oil is an important parameter in viscosity oil characteristics. Different refrigerants should be selected accordingly. If the viscosity of refrigeration oil is too high, the mechanical friction power, friction heat and starting torque will increase. On the other hand, if the viscosity is too small, the required oil film cannot be formed between moving parts, so that proper lubrication and cooling effects cannot be achieved.

(3) Cloud point The cloud point of frozen oil refers to the temperature at which paraffin begins to precipitate in the frozen oil when the temperature drops to a certain value, making the lubricating oil turbid. The cloud point of refrigerating machine oil used in refrigeration equipment should be lower than the evaporation temperature of refrigerant, otherwise the throttle valve will be blocked or the heat transfer performance will be affected.