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Vskills Certified Car AC Mechanic Table of Content

Table of Content



  • Safety Precautions
  • Introduction
  • Air Bags (Supplementary Restraint system SRS)
  • Electrical
  • Refrigerant circuit

Various factors in Refrigeration Cycle

  • All matter can be in any 3 states
  • Methods of Refrigeration
  • Basic Refrigeration Cycle
  • Description of each phase as follows
  • Condensation
  • Expansion
  • Vaporization
  • Ton of Refrigeration
  • Example
  • Solution
  • Ambient temperature
  • Example
  • Heat of Compression

Refrigerant & Oils

  • Refrigerants
  • Refrigerants over the years
  • Identifing Refrigerants by number
  • Refrigerant-12(R-12)
  • Refrigerant-R-22
  • Refrigerant-R-134A
  • Other numbering codes
  • Refrigerant are also classified according to three levels of Toxicity & Flammability
  • Flammability
  • Other Classifications
  • Primary Refrigeratants
  • Desirable Properties of refrigerants
  • Environmental Impact of CFC & Other Refrigerants
  • Ozone Depleting Potential ( ODP)
  • R12 and R134A
  • Warning- Do not mix R12 With R134a. Make Sure you use the proper Oil
  • Purpose of A/C Refrigerant
  • Safety Rules for refrigerant
  • Importance of oil
  • Double End Capped (DEC) PAG and mineral Oils

Identification of compressor

  • Compressor
  • The function of reciprocating compressor
  • The function of swah plate compressor
  • Purpose

Identification of mechanical devices used in car air conditioning unit

  • Compressor
  • Condenser
  • Type of Condensers
  • Receiver-Drier
  • Evaporator
  • Accumulator
  • Refrigernatlines
  • A/C Blower motor
  • DUCT System

Identification of control devices of car air- conditioning cost.

  • Compressor Clutch control
  • Function of clutch coil
  • Function of dual pressure switch
  • Function of Thermo stable expression valve and orifice tube
  • Purpose- HP
  • Working
  • Orifice tubes
  • Function of thermostat
  • Thermostat control

Identification of safety devices at car air conditioning unit

  • Compressor operating controls
  • Ambient Temperature Switch
  • Thermostatic Switch
  • Low pressure cut off switch
  • High pressure relief vaive
  • Pressure Sensing (Cycling) Switch
  • Thermal limiter and superheat switch
  • Evaporator controls
  • Pilot Operated Absolute Valve (POA)
  • Valves in Receiver (VIR)
  • Evaporator Temperature Regulator Valve (ETR)
  • Cooling Fan Temperature Switch
  • High pressure fan switch
  • A/C ‘ON’ fan Switch
  • A/C fan control switch
  • Driveability Compressor Controls
  • Wide open throttle cutoff switch
  • Wide open throttle cutoff switch
  • Low vacuum switch
  • Power Brake time relay
  • Power Steering pressure cutoff switch
  • High Coolant Temperature Switch (HCTS)
  • Anti Dieseling Relay
  • Anti Dieseling relay

Function of Car Air conditioning system

  • Compressor
  • Condenser
  • Discharge line
  • Receiver driver
  • Evaporator Expansion value
  • Liquid line
  • Blower fan A
  • Suction line
  • Radiator line
  • Here’s now an air conditioning system and its component work
  • Features : Displacement (cc) 161 161 Displacement*
  • Details Product Description Specification:

Types of current

  • Types of electrical supply ( Voltage )
  • Type of current
  • AC supply
  • Alternative voltage

Identification of instruction from the data given on the dial

  • Data contained on the measuring instrument dial
  • Measuring range and measuring units
  • Types of current


  • Types of Multimeter
  • Multimeter as a DC voltmeter
  • Multimeter as a DC ammeter
  • Multimeter as an ohmmeter
  • Multimeter as a AC voltmeter
  • Method of measuring DC voltages
  • Method of measuring AC voltage
  • Method of measuring resistance
  • Method of use
  • Application of a multimeter
  • Types of multimeter

Measuring voltage and current using multimeter

  • Multi – range meter
  • Meter scale of multi – range meter
  • Multi – meter
  • Identify the scale to take reading
  • Multimeter as DC VOLMETER
  • Multimeter as DC AMMETER
  • Multi – meter as AC VOLMETER
  • Multi – meter as AC AMMETER
  • Multi – meter as OHMMETER
  • Resistance zero setting

Electrical Part of an air conditioning in car

  • The main electrical parts where as follows
  • Parts used in the system
  • Various parts are connected into the circuit
  • Electrical circuits

Inspection of the car Air conditioning system



  • Reason for Recovering Refrigerant
  • Definitions
  • Method of Recovery
  • Passive method
  • Charge migration
  • Use of System’s Compression Compressor
  • Active Method of Recovery
  • Vapor Recovery
  • Liquid Recovery

Retrofit CFC Filled car A/C with HFC

  • Retrofitting of CFC filled car a/c equipment with the HFC 134a refrigerant
  • Need to Retrofit CFC filled car a/c with HFC 134a and its advantages
  • Precaution to be taken when retrofitting CFC filled refrigerator with HFC – 134a

Evacuation of the Refrigeration System

  • Evacuation
  • Why Evacuate
  • How do we evacuate the system
  • Boiling point of water at various pressures
  • Need for a vacuum pump
  • What type of vacuum pump?
  • Construction of two stage Rotary Vacuum Pumps
  • Rotary Pumps
  • Rotary vane Pumps

Charging Refrigerant in a system

  • Refrigerant charge quantity
  • Charging by liquid or vapor
  • Vapor charging
  • Liquid charging
  • Charging Accurately
  • Refrigerant Charging
  • Charging with a charging cylinder
  • Charging by weight
  • Charging by sight glass
  • Charging refrigerant using frost line method

Performance of Auto A/C system

  • Check performance
  • How to read the graph
  • Example


  • Periodic maintenance
  • Review of Safety

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