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OBJECTIVES IDENTIFY AND COMPARE THE STATE
OF REFRIGERANT IN EACH SECTION OF A/C SYSTEM.
EXPLAIN PURPOSE OF SYSTEM COMPONENTS.
COMPARE THERMOSTATIC EXPANSION VALVE TO FIXED ORIFICE VALVE.
93C & 91L
Compressor
Refrigerant Pump Increases Pressure
and Temperature Several Types Separates High and
Low sides of system Oil is stored in
crankcase (sump)
Compressor Malfunctions
Malfunctions evident following ways;– Noise– Seizure– Leaks– High inlet and low discharge pressure
Discharge Hose
CONTAINS HIGH PRESSURE. SYNTHETIC RUBBER WITH NYLON
BARRIER LINING. 13/32 ID. PREFORMED METAL ENDS WITH FITTINGS.
Condenser Liquefies heat laden vapor. Receives Maximum Air flow. Hot vapor enters top of condenser. Hot Liquid leaves bottom of condenser. Refrigerant flows through condenser
coils and transfers heat to coils and fins. Fins transfer heat to air passing over
them.
96C & 97C109L
Conventional Tube and Fin
Parallel Two Path. Mechanically expanded tube to fin joints. Circular Tubes.
Evaporator
Dehumidifies the airstream. Under ideal conditions, refrigerant boils to
complete saturation 3/4 of the way through Evaporator.
Flooded evaporator means is full of liquid refrigerant with no room for expansion.
Starved evaporator means all refrigerant is boiled in the first quarter of the evaporator.
100C & 110L
Receiver Drier
Located between condenser and metering device
Assures only liquid reached expansion valve
Contains a chemical drying agent (Desiccant)
96C & 110L
Hoses and Lines
NOTICE: Do not use wormgear style clamps for repairing leaks in Nylon barrier hose fittings. Always repair Nylon barrier hose with the appropriate bubble style crimp fitting.
103C98L -102L
Liquid Lines
Condenser to the metering device 5/16 or 1/4 inch ID. Made of rubber, nylon, copper, steel or
aluminum. Contains high pressure liquid! Has sight glass
Thermostatic Expansion Valve Located on inlet side
of evaporator. Used to control
evaporator temp. Variable orifice can
vary on pressure, temperature or both.
Can malfunction in open or closed position.98C
102L
H-Valve Is a Expansion
Valve: Chrysler 1979 and later.
Has internal sensing bulb for low side temperature.
Low Pressure Cut Out Switch for low R-12 Charge.
Thermostatic Switch Senses Evap temp to control clutch operation. 99C & 104L
Valves In Receiver (VIR)
Three different components– TXV– Receiver/Drier– Pilot-operated-
absolute suction throttling valve
Compressor runs all the time.
Page 95C
Orifice Tube
Calibrated Restrictor Different color = different Orifice size. Mesh Filter Screen. Meters refrigerant into evaporator as low
pressure liquid.100C & 105L - 107L
Accumulator
Located between evaporator and compressor.
Primary function is to separate the vapor from the liquid and oil.
Location for desiccant.
102C & 107L
Recommended