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Air conditioner compressor exhaust overheating refers to the exhaust air temperature being too high, which may cause the compressor to protect itself from damage caused by the motor coil temperature being too high. When the exhaust temperature exceeds 95°C (the temperature varies from brand to brand), the air conditioning system protection device will automatically disconnect the working power supply of the compressor, so as to protect the compressor from damage.
So, what causes the exhaust temperature of the air conditioner compressor to be too high? How do we troubleshoot and how to solve it? Generally speaking, most of the following reasons are the following, you can make a reference.
1. Common causes of excessively high exhaust temperatures
1. The filter screen of the return pipe is blocked
If the return pipe filter is blocked, usually the top temperature of the refrigeration compressor is too high, and the exhaust basically has no temperature and pressure, in addition, the four-way valve can not be pushed to reverse when heating, the pressure at the two stop valves of the gas and liquid pipes is basically the same, and the total return air pipe is frosted after the filter. This situation is also easy to solve, if it is dirty, you can clean the main return pipe filter, if it is an ice blockage, you need to use a filter to remove the water from the system.
2. Too much or too little refrigerant
To be clear, whether it is too much refrigerant or not enough refrigerant, it can cause the machine to report overheating protection. When there is too much refrigerant, the overall pressure of the system becomes high, and the high pressure increases, resulting in too high exhaust air temperature protection; when the refrigerant is insufficient, the amount of refrigerant supplied to the evaporator will decrease, resulting in high evaporation temperature, which will lead to overheating of the compressor motor coil, causing the compressor body pressure to become high, and the high pressure will increase, resulting in too high exhaust temperature protection.
3. The condensation temperature is too high
If the condensation temperature is too high, it means that the heat dissipation of the external unit of the air conditioner is not good, and the heat cannot be taken away, which leads to the high exhaust temperature over time.
4. The pipeline of the refrigeration system is blocked
The refrigeration system is clogged, and it is possible that the top temperature of the compressor is very high, but the exhaust temperature is not high, and the top temperature of one or more other presses is very low. The reason is that this compressor cannot absorb the refrigerant, which causes the refrigerant to be deflected to other compressors, resulting in excessive suction capacity of other presses. The suction pipe of the faulty compressor can be welded down and the suction filter can be cleaned.
5. The temperature probe is abnormal
The exhaust temperature probe of the outdoor unit detects an excessively high temperature and transmits the detected temperature data back to the motherboard, which determines that it exceeds the safe limit value based on this data, so it issues a command to force the machine to stop.
In the process of maintenance, we have to doubt the accuracy of the temperature data of this detection. Therefore, we have to use a multimeter to measure the resistance value of this exhaust temperature sensor to see if it is damaged or the resistance drift causes the measured temperature to be inaccurate. If the sensor is damaged, it means that the data it provides to the motherboard is wrong", causing the motherboard to falsely report the fault. At this time, we just need to replace the sensor for him. At the end of the article, we will send a major brand of air conditioning sensor resistance to you for your reference
Second, the case of excessive exhaust temperature protection
Three modular units of multi-unit mainframe have been installed in some office buildings in Chengdu. Two of them have a power of 61.5KW, while the other has only 28KW. However, these units often had reports of exhaust high temperature protection, which was very troublesome for the maintenance masters, who could not find the source of the problem and asked for our help.
After arriving at the site, the No. 1 machine was tested. It was found that when the unit was loaded to high frequency, the temperature at the top of the shell of the compressor continued to rise, reaching an astonishing 115 °C, but at this time, the high pressure pressure was 3.2MPa, although it was a little low, but it was still within the normal range. However, according to the maintenance master, these machines are filled with refrigerant in strict accordance with the standard when they are installed, and the static pressure is also normal, so the possibility of insufficient refrigerant is ruled out.
To add insult to injury, when we looked at the No. 2 compressor at the same frequency, we found that it had a top temperature of only 80°C, in stark contrast to the No. 1 compressor. Why is there such a big difference in the exhaust temperature of two identical compressors running at the same frequency of the same main engine?
After on-site analysis, we initially believed that the problem might be caused by a clogged compressor, so we cut open the suction and exhaust lines of the compressor to investigate. It turned out that the suction port of the compressor was blocked by a foreign object. This is the real culprit of the problem that has been plaguing the maintenance master! This is the first possibility mentioned at the beginning of this article, "the return air filter is blocked", which leads to insufficient suction volume, which causes the exhaust temperature to rise.
This case is caused by system blockage, and the blockage is preliminarily determined to be that the toner of the copper pipe glue plug enters the copper pipe and is not carefully filled with nitrogen for cleaning, and the suction port is blocked due to long-term operation and accumulation, resulting in abnormal suction and exhaust of the heart compressor of the system, resulting in exhaust temperature protection.
Finally, I would like to send you a multi-online sensor resistance table, if this article is helpful to you, please also help forward it, thank you~