The air conditioner does not refrigerate and the external unit does not turn on. Reasons are as follows:1, the indoor machine and external fan is normal work, you can see if the compressor work, if the compressor doesn’t work, can use the multimeter to measure the compressor to see if there is 220 V voltage, if there is a voltage, then there is something wrong with the compressor start capacitance, if change the capacitance still doesn’t work, so that the compressor out of the question.2, there is no 220 V, indicating that there is a problem with the indoor electrical equipment, 220 V voltage, compressor capacitor is not a problem, so the main is to check whether the speed of the fan is normal, if not normal, may be the fan capacitor is broken, running for a long time, the compressor will overheat start the heat protector action.3. If the fan, voltage and capacitor are normal, you can check whether the external fan is clean. If there are stains, clean them.4, if the refrigeration effect is not good, you can check whether the filter element of the machine is clean. If there are stains, then take out the filter element and clean it. At the same time, remove the dust on the mouse cage and see whether the evaporator of the machine is clean.5, the air conditioning is not very good, the other is very good, just look at the copper pipe outside there is no white frost, if there is white frost is fluoride.If there is no frost, touch the pipe to see if it is frozen. If it is not frozen, it is fluoride free. If it is not, check for leaks and vacuum fluoridation.1. The circuit board of air conditioning may be broken, because the computer version is used to control air conditioning, if it is outside, then it is because the computer’s main board is broken.2. There may be freon leakage, or there may be no freon, so the air conditioning cannot be heated.3. There may also be a problem with the capacitor of the air conditioner.