2. When it is detected that the high and low pressure of the system is higher than the normal value, according to the formula, the common fault is that there is too much air or refrigerant added in the system. At this time, it is necessary to vacuum again and add an appropriate amount of refrigerant to solve the problem. But there is another situation, that is, poor heat dissipation, especially when the ambient temperature is relatively high, which often leads to worse heat dissipation. The reasons for this failure are generally the blockage and dirt of the heat sink, the insufficient speed of the cooling fan and so on.
3. When the air conditioning system is working, if the pressure gauge pointer keeps shaking, it means that there is moisture in the system. To solve this problem, it is generally necessary to vacuumize again, and the vacuumizing time must be no less than 15 minutes. If necessary, the drying bottle needs to be replaced to completely drain the water from the system.
4. When the pressure drops, there are two possibilities: one is system jam. When the system is blocked, there will be throttling at the blocked part, and there will be obvious temperature difference at the throttling part. You can find the problem by touching it with your hands. Another possibility is that the refrigerant leaks, resulting in insufficient refrigerant. This situation is more common. At this time, you must use the air conditioner detector to find out the leaking part, or replace or repair it.
Run the air conditioning system (the engine should maintain a certain speed, generally 1500r/min, and only idle speed will affect the accurate diagnosis of faults), and observe the pressure gauge group (for R 12 or R- 134a, the normal working pressure is low pressure side 1.8 ~ 2.65438).