1534 / 1575
HVAC
37
HVAC
Step
Inspection
Action
13
Inspect piping connections for
looseness Are piping connections
loose?
Yes
Tighten connections to specified torque. If the
vane makes a noise, add 10ml of compressor
oil to the A/C compressor. Verify that the noise
is no longer heard.
Adjust refrigerant to specified amounts.
No
If the vane makes a noise, add 10ml of com-
pressor oil to the A/C compressor.
Verify that the noise is no longer heard. Adjust
refrigerant to specified amounts.
14
Verify whether malfunction is in
expansion valve, air mix and
compressor oil or elsewhere Does
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-pressure value
hardly increases?
Yes
Go to next step.
(Pressure hardly increases.)
No
Go to step 17.
15
Verify whether a malfunction is in
compressor oil amount and a/c
compressor or elsewhere when
engine is racing, Does high-
pressure value increase?
Yes
Return to step 3.
No
Go to next step
16
Verify whether malfunctions is in
compressor oil amount or a/c
compressor after compressor oil
is replenished each 10 ml, Does
high-pressure value increase?
Yes
Troubleshooting completed.
(Explain to cus-
tomer that cause was insufficient compressor
oil.)
No
Replace A/C compressor.
(Cause is defective
AC compressor)
17
Verify whether malfunction is in
expansion valve or elsewhere Is
only refrigerant low-pressure val-
ue high?
Yes
Go to step 20.
No
Go to next step
18
Verify that air mix is installed se-
curely and properly Are heater
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and air mix rods securely and
properly installed?
Yes
Go to next step
No
Repair or install links, cranks and rods securely
in proper position.
19
Verify that expansion valve heat-
sensing tube within cooling unit is
positioned securely and correctly
Is expansion valve heat-sensing
tube within cooling unit securely
installed in proper position?
Yes
Replace expansion valve, then go to next step.
(Since valve opens too much, replacement is
necessary.)
No
Install heat-sensing tube securely in proper po-
sition, then go to next step.
20
Verify that malfunction symptom
occurs after repair Does cool air
blow out?
(Are results of refriger-
ant system performance test
okay?)
Yes
Troubleshooting completed.
Explain repairs to customer.
No
Recheck malfunction symptoms, then repeat
from step 1 if malfunction recurs.