A/C Bad Phenomenon
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A/C Pressure Condition
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Other Bad Phenomenon
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Result of Diagnosis (Primary Cause)
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Causes
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Counter Measures
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Insufficient cooling |
High pressure side (discharge pressure)
is high |
Sight glass is clear (liquid
refrigerant stream) |
It is difficult to appear bubbles in
the sight glass even if water is splashed to condenser coil |
Over charging |
Take away extra refrigerant from the
circuit |
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Refrigerant don't disappear in the
sight glass, even after for around 2sec after turning off A/C switch |
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High pressure side is very high in idle
speed |
Some hot air comes to front face of
condenser |
Condenser outlet air or radiator outlet
heated-air flow back to front face of condenser |
Close heated-air recirculating place by
sealing materials or rubber sheet |
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Much air in refrigeration circuit |
Replace R/D, charge regulated amount of
refrigerant after evacuation |
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Insufficient air flow for
condenser |
Condenser fin is clogged |
--------------- |
Clean condenser coil |
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Small air flow volume of condenser
fan |
Malfunction of condenser fan |
Replace condenser fan |
No cooling |
High pressure side is high, low
pressure side (suction pressure) is low |
Discharge pressure is very high after
turning on the A/C switch, and bubbles are seen in the sight glass (if charge valve is located
after R/D, discharge pressure is unknown) |
--------------- |
Choking between compressor and R/D |
Remove clogged materials, or replace
condenser |
Insufficient cooling, or no
cooling |
High pressure side is low, low pressure
side is low |
Bubbles are seen in the sight
glass |
Compressor oil oozes at the pipe
fittings and components, and response on leak detecter |
Gas (refrigerant) leaks from the pipe
fittings or other components |
Retighten the fittings or replace the
parts |
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|
At first, bubbles appear after that
bubbles clear in the sight glass |
--------------- |
Maladjusted TXV (too much closed), or
gas leakage from temperature sensing bulb |
Readjustment of TXV, or replace
expansion valve |
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TXV choking |
Remove choked materials, or replace TXV
and receiver dryer (R/D) |
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Not cools after continuous running, and
after a short time it cool again repeatedly, and airflow volume is normal |
TXV icing due to inside frozen
water |
Replace R/D, and charge refrigerant
after evacuation |
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No air flow, or small air flow
volume |
Evaporator coil fin stuffed with
dust |
Clean evaporator coil fin, or replace
evaporator coil |