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Automotive Air Conditioning Training Manual

Nov 24, 2015

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  • AutomotiveAir Conditioning

    TrainingManual

  • 1(I) TheoryThe four major function..........................................................................................3Understanding heat................................................................................................4Change of state......................................................................................................7Pressure & temperature relationship......................................................................8The Ozone Layer....................................................................................................9R134a properties................................................................................................... 10Principles of air conditioning.................................................................................. 12

    (II) System typesExpansion block valve system...............................................................................13Parallel flow condenser system............................................................................. 14Orifice tube system................................................................................................15Expansion valve dual system.................................................................................16

    (III) ComponentsCompressors..........................................................................................................17Clutches.................................................................................................................22Lubrication............................................................................................................. 23Condensers.......... .................................................................................................24Foam seals............................................................................................................ 25Condenser electric fans......................................................................................... 25Evaporators............................................................................................................26Thermal expansion valve.......................................................................................27Super heat............................................................................................................. 29Orifice tube............................................................................................................ 30Filter drier receiver................................................................................................. 31Accumulators.........................................................................................................32O rings.................................................................................................................33Hoses.....................................................................................................................34Charging ports....................................................................................................... 35Wiring A/C systems................................................................................................36Blower speed control............................................................................................. 37Compressor cycling control....................................................................................38Protective sensors................................................................................................. 42Temperature control...............................................................................................48Mode control..........................................................................................................49Electronic temperature control (ECC).................................................................... 51

    (IV) RetrofittingIntroduction............................................................................................................53Procedures.............................................................................................................54

    Automotive Air Conditioning Training Manual

  • 2Automotive Air Conditioning Training Manual

    (V) EquipmentRecovery&Recycling equipment............................................................................56Evacuation equipment...........................................................................................57Charging stations...................................................................................................59Combination units..................................................................................................60Refrigerant safety...................................................................................................61Leak detections & detectors...................................................................................62

    (VI) ServicingLubrications............................................................................................................65Flushing a contaminated systems..........................................................................66Preparations...........................................................................................................67Testing conditions.................................................................................................. 68A/C performance check......................................................................................... 69Faulty performance of A/C systems.......................................................................72A/C system to noisy............................................................................................... 74A/C system emits unpleasant odours ................................................................... 75The condenser does not dissipate enough heat....................................................76Incorrect refrigerant amount...................................................................................77Compressor displacement regulation valve defective............................................78Expansion valve defective..................................................................................... 79Electric compressor clutch slips or does not engage.............................................80Ice on the evaporator core..................................................................................... 81Compressor damaged........................................................................................... 82Hot air infiltrated in the passenger compartment .................................................. 83Blockage in the A/C system circuit ........................................................................84

  • To be effective, the automotive air conditioner must control four (4) conditions within the vehicle interior:

    It must cool the air

    The four major functions

    It must circulate the air

    It must purify the air It must dehumidify the air

    These functions are essential if passenger comfort is to be maintained when the ambienttemperature and humidity are high.By performing these functions, the air conditioner maintains the body comfort of the passengers.

    Theory

    3Automotive Air Conditioning Training Manual

  • Understanding heat

    What is heat?

    To understand just how an air conditioning system works, we must first understand the nature of heat.

    For a simple definition we may say that heat is energy. The meshing of gears, the turning of wheels cause friction which results in heat. Combustion (fire) gives off heat. The burning of sun radiates heat to the earth's surface.

    Heat in the correct amount will provide life and comfort. Heat in either extreme - extreme to much or to little - will be uncomfortable.

    The control of temperature means the control of comfort.Air conditioning is a method of controlling heat.

    When is heat hot?When is heat cold?

    All substances contain heat. Something "feels" hot when it is warmer than our body temperature. When something contains less heat than our bodies, we say it feels cold!Cold is merely the removal of some heat.

    Science tells us that a measurement called "Absolute Zero" is the point at which all heat is removed from an object (approximately -273 C). Any substance above this absolute zero temperature retains some heat.

    The burning of the sun radiates heat to the earth.

    Theory

    4Automotive Air Conditioning Training Manual

  • 100 KCAL

    Heat measurement

    A temperature reading gives us the heat intensity of a substance and not the actual quantity of heat.

    Heat quantity is measured in "KILOCLORIES" (KCAL's). One KCAL is the amount of heat required to raise the temperature of one kilogram of water one degree Celsius (at sea level). This quantity measurement is used in air conditioning to describe heat transfer during changes of state.

    What causes heat to move?

    Heat always moves from the hotter objects to the colder one. Whenever there is a transfer difference between two objects, the heat energy will be transferred from the warmer object to the cooler one until both objects stabilize at the same temperature.

    This is known as the law of heat transfer, and is the basis of air conditioning operation.

    When a hot cup of coffee is set aside for some time, it becomes cold. Heat moves out of the hot (90 C) coffee into the cooler (25 C) surrounding air. In time the coffee will reach the temperature of the surrounding air.

    90 C 25 C

    Ambient 25 C

    Understanding Heat

    All substances contain heat

    The average person requires a comfort zone of approximately 21 C