Lifan 620 - Fault Diagnosis Table of Air Conditioning System

4) Dust deposit or deformation of heater fins, and poor ventilation—clean or replace the heater;
5) The hot-water pipe of heater is blocked by scale deposit—replace the heater;
6) Insufficient engine cooling water—check whether leakage exists in cooling system, repair it and
replenish cooling water;
7) Failure of engine thermostat—replace the thermostat;
8) Air exists in the heater core barrel—expel air in the pipe.
ii. Fault diagnosis table of air conditioning system
Table 6-2
Phenomenon & state Cause analysis Measure
1. Air leaks into the system. Re-vacuumize and reinject refrigerant.
2. Excessive refrigerant refill. Expel redundant refrigerant.
3. Excessive lubricant
Expel redundant lubricant or replace with
new lubricant.
4. Poor heat eliminating effect.
Wash and clean dust on the condenser
surface or replace with a new condenser.
Both high pressure and
lower pressure are high
5. Abnormal common cooling fan of
condenser and water tank
Inspect the condenser or replace with a new
one.
1. Insufficient refrigerant. Replenish refrigerant.
2. Leakage of refrigerant exists. Make leak detection, replace leaking parts.
Both high pressure and
low pressure are low
3. O-shape ring is damaged. Replace the O-shape ring.
1. Jaw opening of expansion valve is too
big, or expansion valve is damaged.
Adjust the jaw opening of expansion valve,
or replace with a new expansion valve.
2. Excessive refrigerant refill. Expel redundant refrigerant.
High pressure is normal,
low pressure high
3. Fault of compressor exists. Replace the compressor.
1. Insufficient refrigerant. Replenish refrigerant.
2. Ice plug of expansion valve exists. Replace with a new drier-receiver.
High pressure is normal,
low pressure low
3. Dust exists on evaporator surface or
blockage exists in the evaporator.
Clean the evaporator surface or replace
with a new one.
1. Compressor efficiency decreases.
Inspect the compressor or replace with a
new one.
High pressure is low,
low pressure high
2. Air duct is blocked.
Adjust jaw opening of expansion valve or
replace with a new expansion valve.
1. Stop the machine, low pressure
increases quickly—system ice plug.
Replace with a new drier-receiver.
High pressure is low,
low pressure negative
2. Stop the machine, low pressure
increases slowly—system ice plug.
Clean the system.
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