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HVAC
The areas for inspection (steps) are given according to various circuit malfunctions. Use the chart below to verify
the symptoms of the trouble in order to diagnose the appropriate area.
No. Troubleshooting Item
Description
1 Air from vents not cold enough
Magnetic clutch operates but A/C system malfunction
2 No cool air
Magnetic clutch does not operate
3 Noise while operating A/C system Noise from magnetic clutch, A/C compressor, hose or
refrigerant line
1 Air from vents not cold enough
TROUBLESHOOTINGHINTS
•
Drive belt malfunction
Step 1
•
Malfunction in blower unit or condenser
Step 4, 5
•
Malfunction in receiver / drier, expansion valve ( valve close too much) or expansion valve heat-sensing tube
installed incorrectly
Step 8, 9
•
Malfunction in refrigerant lines
Step 10- 13
•
A/C compressor system malfunction, insufficient compressor oil
Step 16
•
Too much compressor oil, expansion valve heat-sensing tube installed incorrectly, or malfunction in expansion
valve or heater unit’s air mix link system
Step 18- 19
1
2
3
4
INSPECT DRIVE BELT
See whether the belt is existing or fitted
with correct tension.
INSPECT REFRIGERANT SYSTEM
PERFORMANCE
Perform refrigerant systemperformance
test (ReferAC system performance test)
Is operating normal?
VERIFYWHETHERMALFUNCTION IS
IN BLOWER UNIT INTAKE AND
CONDENSERORANOTHER
Are refrigerant’s high-pressure and low
pressure values both high?
INSPECT BLOWER UNIT INTAKE
Is blower unit intake clogged
Yes
Go to next step
No
Adjust or replace drive belt.
Yes
Operation is normal. ( Recheck
malfunction symptoms.)
No
Go to next step
Yes
Go to next step.
No
Go to step6.
Yes
Remove obstruction. (Ifairdoesnotreach
evaporatorwithin coolingunit, heat
exchangedoesnot occur and refrigerant
pressurebecomeshigh, therefore, removal
obstruction is necessary.)
No
Go to next step
STEP INSPECTION
ACTION
TROUBLESHOOTING CHART (B)