AUX air conditioner service manual
209
Phenomena：Refrigerating efficiency was unsatisfactory, outdoor unit stopped to run after it operated
for some time.
Cause Analysis: air conditioner was installed last year, and failed to run properly since then.
Maintenance personnel checked the air conditioner many times, and had following data: running
current was 12.5A, pressure was 5kg.f/com2, inlet wind temperature was 12 Celsius Degree, and
outlet wind temperature was 30 Celsius Degree. From these data, air conditioner was normal, current
of air conditioner rose after it run for some time, outlet wind temperature rose gradually. After 1.5
hours, air conditioner was in protection mode. Maintenance workers judged the outdoor unit was in
heat protection mode, and checked discharge environment of outdoor unit, but condenser was clean
and the outdoor unit was not exposed to the sun. Maintenance workers sprinkled water on the outdoor
unit, it was not in protection mode, so the faults were caused by: 1. faults of compressor; 2 refrigerants
were slightly polluted; 3. problems in line. We checked the system and line, low pressure connection
line was bent where it penetrated the wall, the system was blocked and caused poor cooling efficiency.
Solution: replaced bent line, and air conditioner started to work properly
Experience conclusion: such fault is caused by improper installation, so it is often neglected. To fix
such kind of fault, maintenance workers shall check air conditioner carefully and shouldn’t add
refrigerant or change outdoor unit without careful consideration. Generally, it is bending of connection
line and unsmooth circulation of system that result in fault of air conditioner.
Case 18 Pressure switch was broken
Unit Model：ASF-H41A5/A
Phenomena：Couldn’t produce cooling air
Cause Analysis: Turned on air conditioner for less than 1 minute, “run” indicator and “18”
indicator on control panel blinked, so we presumed that it was in protection mode. High pressure and
low pressure switches worked properly, discharge temperature of compressor is normal. Replaced
outdoor check board, tested the air conditioner, fault remained the same. Turned on air conditioner
again and watched running condition of outdoor unit, we found that air conditioner refrigerated for
one minute, low pressure switch broke off, outdoor unit stopped to work; connected low pressure
protector and tested it, it run normally, low pressure was also normally. So we’re sure that pressure
switch was of poor quality and couldn’t work properly.
Solution: replaced low pressure switch, tested air conditioner and it run properly.
Experience Conclusion: observe faults indicators on control panel which can help us find out causes of
faults.
1. Heating defrosting: “heat “indicator blinks
2. Anti-frozen protection: “run” and “cool” indicators blink
3. Anti-cold wind protection: “run” indicator blinks
4. Over current protection: “run” and “29” indicators blink
5. Low pressure protection: “run” and “18” indicators blink
6. Phase sequence protection: “run” and “time”
7. Fault in Communication: “run” indicator blinks and other indicators extinguish
8. Fault in Sensor: “temperature” indicator blinks
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