Komatsu PC200-8M0 Shop Manual page 1199

100 Air conditioner
Troubleshooting chart 2
4. During cooling, the compressor will not operate smoothly, or at all.
a See "Troubleshooting of compressor system (Air is not cooled)".
Troubled part Probable cause
Compressor
Slack of belt
belt
Trouble in compressor
Compressor
Insufficient compressor oil
Seizing on compressor
Drop of battery voltage
Open or short circuit in coil
Magnet clutch
Wire breakage or defective con-
nection of ground wire
Relay Defective compressor clutch relay See "Testing relays"
Refrigerant Low/high pressure (Operation of
pressure pressure switch)
Dual pres-
Defective dual pressure switch
sure switch
5. During heating, blower fan motor is normal but air flow alone is insufficient.
Probable cause
Large duct resistance
Air leakage through duct joints
Clogging of heater core fins
6. Engine coolant temperature or volume abnormalities during heating or cooling
Probable cause
Low engine coolant tempera-
ture
Low engine coolant level
Insufficient circulation of engine
coolant
The connection of IN and OUT
heater hoses is in reverse.
7. Fan speed abnormalities during cooling
Probable cause
Fan speed is low
8. Other abnormalities
Probable cause
Temperature cannot be con-
trolled
Vent (mode) changeover is not
possible.
FRESH/RECIRC air cannot be
changed over
Excessive compressor oil
Water leakage into the cab
PC200, 200LC, 220, 220LC-8M0
Deflection of belt is large.
See "Testing and adjusting of Air conditioner
compressor belt tension" in the "Testing and
adjusting" in Chapter 30 of the shop manual.
Slip of clutch
Heating of compressor
Slip of clutch
Inspect with multimeter (10 - 20 z)
Check ground cable and joints.
See "Troubleshooting for compressor and
refrigerant system".
See "Troubleshooting with gauge pressure".
See "Troubleshooting for compressor and
refrigerant system".
See "Testing refrigerant (dual) pressure
switch".
Check method
Check the filter for clogging and the duct for crushing.
Check the duct joints by referring to "Testing air leakage
(duct)."
Check heater core fins for clogging
Check method
Warm up engine, and then check engine coolant temperature
Check coolant level in radiator
Check engine coolant piping for clogging.
(Hose, pipe and core)
Check the destination of heater hoses
Check method
See "Testing and adjusting of fan belt and alternator belt ten-
sion" in "Testing and adjusting" in Chapter 30 of the shop man-
ual.
Check method
Select manual mode and change temperature setting.
See "Testing vent (mode) changeover".
See "Testing FRESH/RECIRC air changeover".
See "Handling of compressor oil".
Clogging of drain hole
Check method
SEN06151-00
Remedy
Adjust tension
Repair or replace
See "Handling com-
pressor oil".
Charge battery
Replace
Repair
Replace
See "Troubleshooting
with gauge pressure".
Replace
Remedy
Repair
Repair
Clean
Remedy
Find out cause
Add coolant
Bleed air and correct
Correct
Remedy
Correct
Remarks
Common to cooling and
heating
Cooling only
41
80-100