Solution Methods and Experience Summary Cases for Compressor Faults

Solution Methods and Experience Summary Cases for Compressor Faults

Fault type: compressor turn to turn short circuit

Fault phenomenon: Poor cooling effect, compressor trips and stops.

Cause analysis: The machine can operate normally but the refrigeration effect is poor. Check that there is no dirt or blockage in the heat exchanger, the indoor and outdoor fan speeds are normal, and the measured compressor pressure is normal, but the current is too high. After running for a period of time, the compressor becomes hot, causing it to trip and stop. When starting again, the compressor cannot be started, which can be judged as a short circuit between turns of the compressor.

Solution: Replace the compressor

Experience summary: When diagnosing compressor faults, it is important to carefully eliminate peripheral faults, such as internal fan air volume, external fan air volume, compressor capacitor capacity, etc.

Fault type: Slight cross flow of compressor

Machine model: Split hanging machine, cabinet machine series

Fault phenomenon: Poor cooling effect, compressor trips and stops.

Cause analysis: The machine can run but the cooling effect is poor. Check that the heat exchanger is not dirty or blocked, the indoor and outdoor fan speeds are normal and there is no short circuit circulation phenomenon, the voltage is normal, but the suction pressure is high but the current is small. There is a slight gas flow inside the compressor, causing a decrease in the actual output capacity of the compressor.

Solution: Replace the compressor.

Fault type: Slight cross flow of compressor

Fault phenomenon: Poor heating effect

Cause analysis: The new machine was just installed, with an outdoor ambient temperature of around 7 ℃ and an indoor ambient temperature of around 20 ℃. During the test run, it was found that the heating effect deviated, and the condenser did not frost. The measured current was 10 amperes, and the temperature of the suction pipe was similar to the ambient temperature. The exhaust temperature was only 60 ℃, and the improvement was not significant after adding fluorine. The speed of the internal and external fan was normal, and the environmental ventilation was good. Therefore, it can be judged that there is slight gas cross flow in the compressor. Replace the compressor later. [Source:

Refrigeration Encyclopedia official account] After 10 minutes of commissioning, the air supply temperature is about 43 degrees Celsius, and the machine runs normally.

Solution: Replace the compressor

Experience summary: When testing the machine, it should be judged whether there are any abnormalities based on the usage conditions (ambient temperature), etc. If the compressor is not replaced, the heating effect of the machine will definitely be poor when the temperature is low. This type of malfunction is difficult to diagnose and requires troubleshooting of the entire system.

Fault type: Compressor body leakage

Fault phenomenon: No cooling

Cause analysis: Sand holes were found at the welding point of the compressor base casing, causing refrigerant leakage.

Solution: Replace the compressor

Experience summary: The reason for fluoride leakage is that the welding between the compressor housing or between the housing and the suction and exhaust pipes is not secure.

Fault type: Poor suction and exhaust performance of the compressor

Fault phenomenon: High air outlet temperature

Cause analysis: After checking the user's power supply, the operating current of the compressor was normal, but the outlet temperature was 23 ℃. After removing the compressor and cleaning the refrigeration system, no dirt or blockage was found, indicating poor performance of the compressor. The compressor was replaced and tested for 5 minutes. The outlet temperature reached 13 ℃, and the test continued for half an hour, and the operation was normal.

Solution: Replace the compressor

Experience summary: If this fault occurs, try to check if the system is dirty or blocked first.

Fault type: Poor suction and exhaust performance of the compressor

Fault phenomenon: Poor cooling effect

Cause analysis: After testing the pressure of the air conditioning system, the operating current was normal, but the outlet temperature was 20 ℃, the input pipe temperature of the evaporator was cool enough, and the return pipe temperature was not cool enough. When welding the compressor to measure its suction and exhaust volume, it was found that the suction and exhaust pressure was not enough, resulting in poor refrigeration effect.

Solution: Replace the compressor

Experience summary: When there is no dirt or blockage in the refrigeration system, it is important to focus on checking the performance of key components when there is fluorine leakage.

Fault type: Compressor gas leakage

Fault phenomenon: Poor heating effect

Cause analysis: After the machine was started, the low-pressure pressure remained at 8.0kg.f/C ㎡, with a significant difference between the current and rated current. By adding fluorine, the pressure remained unchanged, and the four-way valve and one-way valve were checked for normal operation. Therefore, it was determined that the compressor was leaking gas, causing a decrease in the suction and exhaust of the compressor, resulting in poor heating effect

Solution: Replace the compressor

Summary of experience: Both the compressor and the four-way valve can cause the air conditioner to not cool or heat, resulting in similar malfunctions. When the machine is operating, touch the valve body of the four-way valve with your hand. If the temperature is uniform and the high pressure is low, the low pressure is high, and it can be judged as a four-way valve malfunction.

Fault type: compressor short circuit to ground

Fault phenomenon: Power on trip

Cause analysis: After starting up, the user's power supply tripped. No leakage or short circuit was found in the user's power supply, electronic control, power supply lines, and indoor and outdoor connection lines. By measuring the resistance values between each terminal of the compressor and the ground, it was found that the resistance value was less than 2M ohms. Therefore, it was determined that the compressor was short circuited to ground

Solution: Replace the compressor with the same model

Experience summary: There are many reasons that can cause tripping after power on. It is necessary to first troubleshoot the user's power supply before inspecting the air conditioning.

Fault type: Poor suction of AC contact tube contacts, causing compressor misjudgment

Fault phenomenon: The air conditioner shuts down when it fails to reach the set temperature

Cause analysis: the machine started up and operated normally, but after a period of work, the outdoor unit compressor was overheated, so the indoor temperature had not reached the set temperature and it was shut down. [Source of this article: Refrigeration encyclopedia official account] After detection, the current suddenly rose after the machine worked for a period of time, and it was found that the one phase suction piece of the AC contactor was not well contacted, which was easy to jump off, resulting in the compressor over temperature protection.

Solution: Replace the AC contactor

Experience summary: When judging the performance of a compressor, it is necessary to fully analyze the reasons in all aspects and not judge compressor faults from a single perspective.

Fault type: Poor suction and exhaust of the compressor

Fault phenomenon: The air conditioner sometimes does not cool down

Cause analysis: The air conditioner can work normally after being turned on for one hour. After one hour, the compressor noise suddenly decreases, the current increases, the low-pressure pressure becomes balanced pressure, and the exhaust pressure becomes 0.4MPA. When the compressor temperature rises, its suction and exhaust capacity decreases, causing the air conditioner to sometimes not cool.

Solution: Replace the compressor with the same model

Experience summary: The suction and exhaust capacity of the compressor is an important factor affecting the refrigeration efficiency of air conditioning.