Fault Finding And Testing - Case 580SR Service Manual

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FAULT FINDING AND TESTING

Overhaul of the air conditioning system should only
be undertaken by a certified specialist refrigeration
engineer using a comprehensive air conditioning
test kit, including a gas leak detector, suitable for
HFC 134a refrigerant gas.
S
WARNING
Before dismantling an air conditioning system for re-
pair the gas within the system must be discharged
and recovered using a certified recovery unit de-
signed for the type of refrigerant gas used in the sys-
tem.
NEVER release refrigerant gas into the atmos-
phere.
ALWAYS wear safety goggles and gloves when
servicing any part of the air conditioning system.
To prevent the entry of any foreign material, observe
the following points:
Z Ensure all tools, gauges, hoses and replacement
parts are kept clean and dry and are suitable for
the type of refrigerant gas used in the system.
Z Clean all hoses and fittings before disconnecting.
Z Cap or plug all openings when disconnected.
Z When adding lubricating oil to the system always
uncap and re-cap the oil container immediately be-
fore and after use. Always ensure the oil remains
free of moisture.
SECTION 50 - CAB HEATING AND AIR CONDITIONING
Preliminary fault finding
Always conduct the preliminary fault finding checks
before performance testing the system.
1. Run the engine at 1000-1200 rpm for 10 min-
utes with the air conditioner set to maximum
cooling and the blower at high speed.
2. Check that the heater temperature control is
switched OFF.
3. Check that the blower fan is operating at all
speeds.
4. Check that the compressor clutch engages
when the temperature control switch is turned
from OFF to ON position. A clicking sound indi-
cates the clutch is engaging. If the clutch fails to
operate it may indicate an electrical problem in
the high low pressure cut out switches or mal-
function of the electrical drive clutch on the com-
pressor.
5. Check the engine cooling fan is drawing cool air
through the condenser.
6. Check the compressor drive belt tension.
7. Check the condenser core and grid is clean and
free of obstruction.
8. Check the cab air filter is clean and free of ob-
struction.
9. Check the evaporator fins are not plugged or ex-
cessively dirty.
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