What's wrong with the cold air conditioner?

Insufficient freon (usually referred to as "insufficient refrigerant"); The air conditioner is not cleaned and maintained for a long time during use; The external environment temperature is too high, and the external machine does not dissipate heat; The power supply line is damaged and the power supply voltage is insufficient; The copper tube between the outdoor unit and the indoor unit is too long. Details of the specific reasons for not cooling: 1, Freon shortage (usually called "refrigerant shortage"): It usually occurs in air conditioners that have been used for three or four years, and the effect of air circulation refrigeration is not very good, because the working condition of air conditioning system decreases with time, because the old air conditioners use Freon as the refrigerant of air conditioners, which will volatilize after long-term use. 2. The air conditioner is not cleaned and maintained for a long time: after the air conditioner is idle for a period of time, a large amount of dust will be adsorbed on the filter screen, blades and wind wheels of the indoor unit, resulting in a low air outlet temperature of the indoor unit, but the wind is not far away, and the indoor circulation slows down, resulting in poor refrigeration effect. 3. The external environment temperature is too high, and the external machine does not cool: the temperature around the outdoor unit of the air conditioner is too high, which will cause the air conditioner to output heat in the radiator without changing the way. When the outdoor temperature generally exceeds 43 degrees, the air conditioner can't send the indoor hot air to the outside, which leads to the air conditioner can't cool. 4. Insufficient power supply voltage: the power supply line is damaged, or the voltage cannot reach the normal level during the peak period of power consumption, which affects the refrigeration effect of air conditioning. 5. The copper pipe between the outdoor unit and the indoor unit is too long: too long ventilation pipe will lead to low heat transfer efficiency and the air conditioner will not be cooled.