Overheating of air conditioning compressor exhaust, that is, too high exhaust temperature, is a common problem. When the exhaust temperature exceeds a certain threshold, the protection device of the air conditioning system will start and automatically cut off the power supply of the compressor to prevent the motor coil from being damaged by high temperature. So, what exactly causes this phenomenon? How to investigate and solve it?
Usually, this is mostly related to the following situations:
1. Common causes of excessive exhaust temperature
The return air pipe filter is blocked. This will cause the top temperature of the refrigeration compressor to rise, while the exhaust temperature is relatively low. At the same time, in the heating mode, the four-way valve cannot be reversed normally, the stop valve pressures at the gas and liquid pipes are similar, and the part of the total return air pipe after the filter will be completely frosted. In this case, if it is due to dirt blockage, just clean the total return air pipe filter; if it is due to ice blockage, it is necessary to remove the moisture in the system through the filter.
2. The influence of refrigerant quantity
Too much or too little refrigerant will cause overheating of the air conditioning compressor exhaust. When there is too much refrigerant, the overall system pressure will rise, and the high pressure pressure will rise accordingly, which will trigger the protection of excessive exhaust temperature. On the contrary, insufficient refrigerant will reduce the amount of refrigerant received by the evaporator, increase the evaporation temperature, and then overheat the compressor motor coil, and the compressor body pressure and high pressure will also increase, eventually triggering overheat protection.
3. Influence of condensation temperature
Excessive condensation temperature will affect the heat dissipation effect of the air conditioner outdoor unit, resulting in the inability to effectively dissipate heat, and long-term accumulation will cause the exhaust temperature to continue to rise. In order to solve this problem, we need to check whether the air conditioner outdoor unit is close to the wall, whether the exhaust vent is blocked, and whether there is heat radiation around. At the same time, it is also necessary to ensure that the outdoor unit heat exchanger is clean and the fan is running normally to ensure the heat dissipation effect of the outdoor unit.
4. Problems with blocked refrigeration system pipelines
When the refrigeration system pipelines are blocked, the top temperature of a compressor may rise abnormally, while the exhaust temperature remains low, while the top temperature of one or several other compressors is relatively low. This is usually because the compressor cannot inhale the refrigerant, causing the refrigerant to flow to other compressors, causing the intake volume of other compressors to be too large. To address this problem, you can try to weld off the suction pipe of the faulty compressor and clean the suction filter.
5. Impact of abnormal temperature probe
When the outdoor unit exhaust temperature probe detects an excessively high temperature and transmits this data back to the main board, the main board will determine that the temperature has exceeded the safety limit based on the data, and then issue a command to force the machine to stop running.
During the inspection process, we need to verify the accuracy of the detected temperature data. To this end, we can use a multimeter to measure the resistance of the exhaust temperature sensor to determine whether it is damaged or the resistance value changes affect the accuracy of the temperature data. If the sensor is indeed damaged, the data it provides to the main board will be inaccurate, which may cause the main board to misjudge and issue a fault report. At this time, simply replacing the sensor can solve the problem.