| Common issues | Possible Causes | Correction Method |
| Compressor not working | ①Power switch and fuse failed |
Replace with new fuse and reconnect the circuits. |
| ②Clutch not activate (too low voltage; no current in coils, wire coils burn out) | Check the clutch circuit, temperature sensor and pressure switch; Replace failed components and electromagnetic clutch | |
| ③Clutch activated (compressor get stuck; belt broken or skidding; clutch skidding) | Replace compressor; Adjust belt tension or replace belt; Check the clutch clearance. | |
| Compressor working but without cooling; Low pressure at input and output | ①Refrigerant leaked completely |
Repair the leakage and re-fill refrigerant |
| ②Compressor valve parts damaged |
Repair or replace Compressor valve parts | |
| ③Expansion valve gets stuck, system refrigerant can not recycle. |
Repair or replace the expansion valve. | |
| ④Drier filter is jammed |
Repair or replace the drier. | |
| ⑤Evaporator fan not work （Circuit impassibility） | Check connection and the fan blade | |
| Insufficient cold air volume. Low pressure reading is high. High pressure reading is normal |
Fan voltage is low Evaporator surface gets stuck Fan variable resistance failure, unable to set to high speed |
Check connection, remove poor contact Clean the evaporator Repair and replace resistance |
| Condenser fan’s air volume is insufficient. Both high pressure and low pressure readings are too high |
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| Both high pressure and low pressure readings are too low |
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| Both high pressure and low pressure readings are too high |
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| High pressure reading is too high, low pressure reading is too low |
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| High pressure reading is normal, low pressure reading is sometimes normal, sometimes in vacuum state, the evaporator frost |
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| Malfunction | Presentation status | Repair Method | |
| Not cooling | Evaporator fan working | Condensing fan does not turn and the compressor works | Check fan connector and whether the fan is damaged. |
| Condensing fan does not turn and the compressor does not work | Check whether the temperature control switch is damaged, whether the relay is engaged, and whether the relay connector is loose | ||
| Condensing fan turn and compressor do not work | Check whether the clutch is damaged, the connector is off and the belt is loose and skid. | ||
| Evaporator fan not working |
Condenser fan turns, and the compressor works | Check whether the speed control switch fails, whether the fan line is disconnected, and whether the fan grounding wire is good. | |
| Condenser fan does not turn, and the compressor does not work | Check whether the fuse is damaged, check whether the relay is normal, and check whether the wiring is loose. | ||
| Compressor works | Evaporation fan and condenser fan all work | 1.The refrigerant is overcharged. Use pressure gauge to check whether it meets the specified pressure value. | |
| 2. Not used for a long time, possible refrigerant leakage. Use pressure gauge to check whether there is refrigerant in system. | |||
| Insufficient cooling capacity | Compressor works | Both the evaporative fan and the condensing fan are working normally, both the evaporator and condenser are normal | Check whether liquid reservoir’s input and output is reversed. Check whether the expansion valve is ice or dirt blocked. Replace the reservoir. Replace the refrigerant. |
| The fan works normally, and other others are normal | Check whether the condenser surface is blocked by the scale. | ||
| Errors | Possible Reason | Repair Method |
| The cooling performance is good at the beginning, after a period of use, the cooling air is insufficient; air bubbles appear in the sight glass; both high and low pressure reading is low | Often driving on bumpy road, causing connection loosen and refrigerant leakage. | Use the leakage detector to find out leakage part, carefully tighten the loose part, and supplement the refrigerant. |
| Not cooling, blows out hot air, expansion valve input and output feel no temperature difference, the low pressure reading is very low. | Improper use. The expansion valve temperature sensor wears out, and the valves worn. | Replace the expansion valve and recharge the refrigerant. |
| Air outlet is not cold, and the compressor’s temperature rises. The low pressure meter drops rapidly, close to the "0" value, and the high pressure reading is high. | The system has impurities, expansion valve, filter screen is blocked, thin frost or "sweat" at the expansion valve. | Open the air conditioning system intermittently, can eliminate the instantaneous blockage. Or remove the expansion valve and clean it with alcohol, and recharge refrigerant. |
| Insufficient cold capacity, evaporator frost; both high and low pressure readings are low. | The internal orifice in the expansion valve does not work | Vacuum the system, replace the expansion valve and recharge refrigerant. |
| After the system is running for a period of time, the cooling capacity gradually decreases, the high pressure reading is high, and the low pressure reading is low. | The desiccator in the reservoir bottle is saturated, and the throttle of the expansion valve is blocked by ice. | Vacuum the system, replace the expansion valve and recharge refrigerant. |
| After opening the air conditioning system, only blows air without cold wind, both high and low pressure reading does not move. | The temperature control switch is in bad contact or the compressor electromagnetic clutch coil is damaged. | Check the temperature control switch with the multimeter; replace the compressor electromagnetic clutch. |
