SECTION 50 - CAB HEATING AND AIR CONDITIONING
23
EXPANSION VALVE
The expansion valve is located underneath the
evaporator in the pressure line leading from the re-
ceiver/dryer and performs the following functions:
1.
METERING ACTION
A metered orifice changes the liquid refrigerant
from a high pressure low temperature liquid to a
low pressure, lower temperature atomized liq-
uid.
2.
MODULATING ACTION
A thermostatically controlled valve within the ex-
pansion valve body controls the volume of liquid
refrigerant passing through the orifice and
makes sure the refrigerant is fully vaporized
within the evaporator. Liquid refrigerant at would
damage the compressor reed valves or freeze
the pistons.
3.
CONTROLLING ACTION
The valve responds to changes in the cooling re-
quirements. When increased cooling is required,
the valve opens to increase the refrigerant flow
and when less cooling is required the valve clos-
es and decreases the refrigerant flow.
Expansion valve - operation
All of the needed temperature sensing and pressure
sensing functions are consolidated into this basic unit
and no external tubes are required for these purposes.
The refrigerant from the condenser and receiver dry-
er enters the thermostatic expansion valve as a high
pressure warm liquid. Upon passing through the ball
and spring controlled metering orifice, the pressure
and temperature of the refrigerant is reduced and
the refrigerant leaves the thermostatic expansion
valve as a low pressure, lower temperature atom-
ized liquid.
The atomized liquid now passes through the evapo-
rator where it absorbs heat before returning via the
expansion valve to the compressor as a warm low
pressure vapour. There are two refrigerant passag-
es in the valve. One passage is in the refrigerant line
from the condenser to the evaporator and contains
the ball and spring type orifice valve.
The other passage is in the refrigerant line from the
evaporator to the compressor and contains the
valve’s temperature sensing element.
Liquid refrigerant flow from the condenser and re-
ceiver dryer is controlled by a push-rod forcing the
orifice valve ball off its seat and the spring exerting
pressure on the ball to keep it on its seat.
During stabilized (vehicle shutdown) conditions, the
pressure on the bottom of the expansion valve dia-
phragm rises above the pressure on the top of the di-
aphragm allowing the valve spring to close the
orifice.
F28691
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Summary of Contents for 580SR
Page 2: ...7 SPICER OFF HIGHWAY AXLE DIVISION 21199 www maskinisten net Copyright...
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Page 13: ...580SR 580SR 590SR 695SR SECTION 00 SAFETY PRECAUTIONS www maskinisten net Copyright...
Page 14: ...2 SECTION 00 SAFETY PRECAUTIONS www maskinisten net Copyright...
Page 19: ...580SR 580SR 590SR 695SR SECTION 01 MAINTENANCE www maskinisten net Copyright...
Page 20: ...2 SECTION 01 MAINTENANCE www maskinisten net Copyright...
Page 24: ...2 SECTION 02 TECHNICAL SPECIFICATIONS 1 www maskinisten net Copyright...
Page 54: ...32 SECTION 02 TECHNICAL SPECIFICATIONS NOTES www maskinisten net Copyright...
Page 56: ...2 SECTION 17 TORQUE CONVERTERS www maskinisten net Copyright...
Page 68: ...2 SECTION 21 TRANSMISSION www maskinisten net Copyright...
Page 86: ...20 SECTION 21 TRANSMISSION Input Intermediate Output F29980 www maskinisten net Copyright...
Page 87: ...SECTION 21 TRANSMISSION 21 NOTE 4WD shown www maskinisten net Copyright...
Page 88: ...22 SECTION 21 TRANSMISSION NOTE 4WD version shown www maskinisten net Copyright...
Page 90: ...24 SECTION 21 TRANSMISSION F27511 www maskinisten net Copyright...
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Page 248: ...182 SECTION 21 TRANSMISSION Remove the clutch piston assy www maskinisten net Copyright...
Page 264: ...198 SECTION 21 TRANSMISSION Remove the clutch piston assy www maskinisten net Copyright...
Page 270: ...204 SECTION 21 TRANSMISSION Remove the clutch piston assy www maskinisten net Copyright...
Page 354: ...2 SECTION 25 FRONT AXLES www maskinisten net Copyright...
Page 494: ...2 SECTION 27 REAR AXLE www maskinisten net Copyright...
Page 578: ...2 SECTION 33 BRAKES SYSTEM www maskinisten net Copyright...
Page 590: ...14 SECTION 33 BRAKES SYSTEM NOTES www maskinisten net Copyright...
Page 714: ...124 SECTION 35 HYDRAULIC SYSTEM NOTES www maskinisten net Copyright...
Page 716: ...2 SECTION 39 CHASSIS www maskinisten net Copyright...
Page 728: ...2 SECTION 41 STEERING SYSTEM www maskinisten net Copyright...
Page 760: ...34 SECTION 41 STEERING SYSTEM NOTES www maskinisten net Copyright...
Page 762: ...2 SECTION 50 CAB HEATING AND AIR CONDITIONING www maskinisten net Copyright...
Page 828: ...68 SECTION 50 CAB HEATING AND AIR CONDITIONING NOTES www maskinisten net Copyright...
Page 837: ...SECTION 55 ELECTRICAL SYSTEM 9 ENGINE LINE DIAGRAM www maskinisten net Copyright...
Page 839: ...SECTION 55 ELECTRICAL SYSTEM 11 SOLENOID VALVE LINE DIAGRAM www maskinisten net Copyright...
Page 840: ...12 SECTION 55 ELECTRICAL SYSTEM LIGHT LINE DIAGRAM www maskinisten net Copyright...
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Page 842: ...14 SECTION 55 ELECTRICAL SYSTEM WORK LIGHT LINE DIAGRAM www maskinisten net Copyright...
Page 852: ...24 SECTION 55 ELECTRICAL SYSTEM ENGINE LINE DIAGRAM www maskinisten net Copyright...
Page 854: ...26 SECTION 55 ELECTRICAL SYSTEM SOLENOID VALVE LINE DIAGRAM www maskinisten net Copyright...
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Page 889: ...SECTION 55 ELECTRICAL SYSTEM 61 LIGHT LINE DIAGRAM www maskinisten net Copyright...
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Page 893: ...SECTION 55 ELECTRICAL SYSTEM 65 HEATER LINE www maskinisten net Copyright...
Page 901: ...SECTION 55 ELECTRICAL SYSTEM 73 ENGINE LINE DIAGRAM www maskinisten net Copyright...
Page 902: ...74 SECTION 55 ELECTRICAL SYSTEM SOLENOID VALVE LINE DIAGRAM www maskinisten net Copyright...
Page 903: ...SECTION 55 ELECTRICAL SYSTEM 75 SOLENOID VALVE LINE DIAGRAM www maskinisten net Copyright...
Page 904: ...76 SECTION 55 ELECTRICAL SYSTEM LIGHT LINE DIAGRAM www maskinisten net Copyright...
Page 905: ...SECTION 55 ELECTRICAL SYSTEM 77 REAR LIGHT LINE DIAGRAM www maskinisten net Copyright...
Page 906: ...78 SECTION 55 ELECTRICAL SYSTEM WORK LIGHT LINE DIAGRAM www maskinisten net Copyright...
Page 908: ...80 SECTION 55 ELECTRICAL SYSTEM HEATER LINE www maskinisten net Copyright...
Page 916: ...88 SECTION 55 ELECTRICAL SYSTEM ENGINE LINE DIAGRAM www maskinisten net Copyright...
Page 917: ...SECTION 55 ELECTRICAL SYSTEM 89 SOLENOID VALVE LINE DIAGRAM www maskinisten net Copyright...
Page 918: ...90 SECTION 55 ELECTRICAL SYSTEM SOLENOID VALVE LINE DIAGRAM www maskinisten net Copyright...
Page 919: ...SECTION 55 ELECTRICAL SYSTEM 91 LIGHT LINE DIAGRAM www maskinisten net Copyright...
Page 920: ...92 SECTION 55 ELECTRICAL SYSTEM REAR LIGHT LINE DIAGRAM www maskinisten net Copyright...
Page 921: ...SECTION 55 ELECTRICAL SYSTEM 93 WORK LIGHT LINE DIAGRAM www maskinisten net Copyright...
Page 923: ...SECTION 55 ELECTRICAL SYSTEM 95 HEATER LINE www maskinisten net Copyright...
Page 924: ...96 SECTION 55 ELECTRICAL SYSTEM STEERING LINE DIAGRAM www maskinisten net Copyright...
Page 967: ...SECTION 55 ELECTRICAL SYSTEM 139 www maskinisten net Copyright...
Page 1028: ...2 SECTION 82 LOADER www maskinisten net Copyright...
Page 1040: ...2 SECTION 84 BACKHOE www maskinisten net Copyright...
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