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Certified AC Plant Mechanic

How It Works

  1. 1. Select Certification & Register
  2. 2. Receive a.) Online e Learning Access (LMS)    b.) Hard copy - study material
  3. 3. Take exam online anywhere, anytime
  4. 4. Get certified & Increase Employability

Test Details

  • Duration: 60 minutes
  • No. of questions: 50
  • Maximum marks: 50, Passing marks: 25 (50%).
  • There is NO negative marking in this module.
  • Online exam.

Benefits of Certification

Rs.3,499 /-

Vskills has developed a new strategic framework for Skill Development for early school leavers and existing workers, especially in the unorganized sector to improve their employability called Trade Employable Skills (TES).

Trade Employable Skills does effective assessment and certification of candidates in different trade disciplines like Electrical, Electronics, Agriculture, Chemical, Automobile, IT, etc to make them job ready.

Why should one take this certification?

To demonstrate clear understanding and practical aspects and to get a visible recognition for this knowledge.

Table of Content

Practice Test

Companies that hire AC plant Mechanic

All small and medium companies need certified employees who have the requisite skills. There are more jobs opening up in the economy on a regular basis with the fast growth of the country.

Apply for Certification

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  • Visa Card
  • Master Card
  • American Express

Safety Practice –fire extinguishers

  • Fuel
  • Heat
  • Oxygen
  • Starving
  • Smothering
  • Cooling
  • Removing one of these factors will extinguish the fire
  • Extinguishing firs

Common basic Refrigeration tools and functions

  • Pressure gauges
  • Compound gauge
  • Thermometer
  • Soap bubble method
  • Sling psychrometer

Setting of Oxy –Acetylene flame

  • Fuel gases used in welding
  • Supporter of combustion gas
  • Temperature and uses of gas lame combinations oxy –acetylene gas flame
  • Oxy – hydrogen gas flame
  • Oxy –liquid petroleum gas flame
  • Oxy –coal gas flame
  • The most commonly used gas flame combination is OXY –ACETYENE
  • Flame types
  • Neutral flame
  • Characteristics
  • Uses
  • Oxidizing flame
  • Characteristics

Tubing –Cutting and bending methodology

  • Types of tubing
  • Soft copper tubing
  • Hard drawn copper tubing
  • Steel tubing
  • Stainless steel tubing
  • Plastic tubing
  • Flexible tubing  
  • Tube cutting
  • Bending tubing


  • Swaging on copper tubing

Flaring flare fitting and testing the joints

  • Flaring necessity
  • Types of flaring
  • Single thickness flare
  • Flared tubing fitting

Efficiency and testing of commercial reciprocating compressor

  • Efficiency of a compressor
  • Mechanical efficiency
  • Compression ratio
  • Volumetric efficiency
  • Performance factor
  • Break horse power
  • Reciprocating compressor as Vacuum pump
  • Checking of external drive compressor
  • Compressor testing methods
  • Types of Reciprocating compressor
  • According to the working position of cylinder
  • According to the method of compression of the  gas
  • According to the number of times of compression of  gas
  • According to the cooling the head of compressor
  • Safety precautions

Measuring voltage and current using multimeter

  • Multi-range meter
  • Multi-meter
  • Multimeter as AV VOLTMETER
  • Multi-meter as AC AMMETER
  • Resistance zero setting

Refrigerants – Hisotry, Classification, Environmental

  • Refrigerants
  • Refrigerants over the years
  • Identifying Refrigerants by number
  • Refrigerant-12
  • Refrigerant- R-22
  • Refrigerant-R-134A
  • Refrigerant Cylinders and Valves
  • Storage cylinders
  • Returnable service cylinders
  • Disposable cylinder
  • Colour code for refrigerant cylinder
  • Refrigerant cylinder valves
  • Remember – refrigerant can be dangerous

Central Air – conditioning plant wiring circuit

  • Motor
  • Protective devices
  • Fuses
  • Thermal overloads
  • Control sequence
  • Interlocking circuit
  • Control Relay

Temperature and pressure controls

  • Types of pressure controls
  • Purpose of the bellow type low pressure switch
  • Liquid line solenoid valve
  • The use, installation and point of electronic thermostat (controller)
  • Indicators lead
  • Parameter programming
  • Description of the parameters
  • Version
  • Technical Data
  • Installation
  • Filling – up and dimensions of the models for paneled  fixing
  • Dimensions of the models for surface fixing
  • Wiring
  • Operating or control type
  • Operating messages
  • Description
  • Maintenance
  • Cleaning

High pressure safety cutout, Safety value and Oil pressure cut out

  • High pressure cut out and functions
  • High pressure safety cut – out
  • High pressure cut-out and functions
  • Types of pressure controller
  • Bellow type
  • Bourdon tube type
  • Range and differential of a pressure switch
  • Differential pressure controller
  • Use of safety valve or relief valve
  • Fusable plug
  • Oil pressure switch use

Classification of commercial compressors and the gasket

  • Gaskets and its use
  • Commercial compressors types
  • Reciprocating compressors

Descaling in shell and tube condenser

  • Method of descaling
  • Tube expender

DRY Expansion Evaporators

  • Dry expansion type evaporators
  • Expansion shell and tube chillers
  • Construction and function
  • Maintenance of dry type chillers
  • Advantages in dry-type chillers
  • Direct and indirect expansion evaporator

Transfer refrigerant to shell and Tube condenser

  • Purging the air from the system
  • Pump down the system is also useful

Air Handling Units and Air Washer in Air-conditioning plants

  • Necessity of de-scaling in chilled water coils
  • De-scaling in AHU and air-washers
  • The arrangement of AHU in Air-conditioning plant
  • Fan Coil Units
  • Air-washer’s applications in Air-conditioning plant

Water circulation pumps

  • Centrifugal pump – parts and functions
  • Dismantling
  • The complete Service of the pump
  • Replace or service
  • Assembly process

Chilled water treatment

  • Importance of water
  • Corrosion
  • Scale
  • Fouling
  • Parameters to be analysed
  • Control of parameters
  • Molybdate
  • Biends of molybdate
  • Corrosion prevention
  • Iron fouling
  • Corrosion

Cooling Towers

  • Cooling water process
  • Atmospheric cooling is usually obtained by three methods
  • Spray cooling ponds
  • Cooling towers
  • Open Tower
  • Close Tower
  • Natural draft cooling towers
  • Forced draft cooling tower
  • Induced Draft cooling Tower
  • Algae
  • The cooling effect can be increased by
  • Limitations
  • Range
  • Approach
  • Drift loss
  • Evaporation loss
  • Blow down
  • Make up water

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