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Q1— Section header —
1.1Briefly explain the operation of a vapour compression system. (2\
1.2Name the FOUR types of compressors used in refrigeration. (4\
1.3Indicate with the aid of a block diagram, FOUR major components of a vapour compression system. (4\
1.4Name the THREE types of evaporators. (3\
1.5State the functions of the following components in a refrigeration system:
1.5.1Accumulator
1.5.2Heat exchanger
1.5.3
1.6What determines the temperature at which a refrigerant will vapori e? (1\ [20]20
Q2— Section header —
2.1SI units and symbols are used for electrical measurements. Redraw and complete the table below in your ANSWER BOOK. COMPONENT SI UNIT SYMBOL
2.1.1Energy
2.1.2Heat
2.1.3Resistance
2.1.4Current (4 1\ (4\
2.2Define the following terms:
2.2.1Work
2.2.2Ohms
2.2.3Current electricity
2.2.4Static electricity (4 2\ (8\
2.3Name FOUR factors determining resistance of a conductor. (4\
2.4What is the difference of a single phase and three phase power
2.5Two resistors of 2 and 4
2.5.1Draw the circuit indicating all the resistors, switch and supply voltage of 230 V. (4\
2.5.2Calculate the total resistance of parallel circuit. (2\ [24]24
Q3— Section header —
3.1Briefly explain FIVE aspect of safe handling of refrigerant containers to ensure that no damage occurs and no refrigerant is released into the atmosphere unnecessarily when transporting them. (5\
3.2Choose a/an item/word from COLUMN B that matches a/an word/item in COLUMN A. Write only the letter (A \next to the question number (3.2.1
3.2.6\ the ANSWER BOOK. COLUMN A COLUMN B
3.2.6Accurate dimension Cutting Remove nut Shaping metal Marking centres Cleaning
3.3Name FOUR parts of a bolt. (4\
3.4What is the name of the blue dial gauge on the left of the service manifold? (1\
3.5Name the TWO types of display of meters and explain the difference between the two display screens. (4\ [20]20
Q4— Section header —
4.1List FOUR appropriate safety equipment all workers should wear hen working with refrigerants (particularly in the liquid phase\ (4\
4.2What do you call the following groups of refrigerants commonly used in South Africa:
4.2.1R717
4.2.2HCs
4.2.3CFCs
4.2.4HFCs
4.2.5HCFCs (5 1\ (5\
4.3Name FOUR types of oil used in refrigeration. (4\
4.4Which type of a rod do we use when joining the following?
4.4.1Copper to steel
4.4.2Copper to copper (2 1\ (2\ [15]15
Q5— Section header —
5.1Why is a hacksaw not a suitable tool to cut piping in the refrigeration system? (1\
5.2How will you prevent moisture migration and heat transfer in refrigerant piping? (2\
5.3Where are the access valves often used in a refrigeration system? (2\
5.4Give FOUR precautions when soldering. (4 2\ (8\ [13]13
Q6— Section header —
6.1State THREE common used types of electronic leak detector. (3\
6.2Name THREE possible hazards when handling refrigerants. (3\
6.3Define viscosity (1\
6.4Describe the term purging. (1\ [8] TOTAL: 1008