Cause analysis: The outdoor unit of Haier air conditioner is installed and used in an environment close to the oil fume emission (such as near the kitchen, the kitchen of the hotel, the place where the oil fume emission concentration is high, and the place where the oil fume pollution concentration of factories and mines exceeds the standard), which causes the heat exchanger of indoor and outdoor units to absorb a large amount of high-concentration oil fume and dust and attach to the heat exchanger, which seriously affects the adjustment effect of the cooling and heating temperature of Haier air conditioner, makes Haier air conditioner unable to work normally, and causes the compressor to overheat.