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SOUTH AFRICAN QUALIFICATIONS AUTHORITY 
REGISTERED UNIT STANDARD THAT HAS PASSED THE END DATE: 

Explain the operation of basic vapour compression refrigeration systems, and identify and explain the function of the components and accessories as well as their retrieval and storage procedures 
SAQA US ID UNIT STANDARD TITLE
116224  Explain the operation of basic vapour compression refrigeration systems, and identify and explain the function of the components and accessories as well as their retrieval and storage procedures 
ORIGINATOR
SGB Air-conditioning Refrigeration and Ventilation 
PRIMARY OR DELEGATED QUALITY ASSURANCE FUNCTIONARY
-  
FIELD SUBFIELD
Field 06 - Manufacturing, Engineering and Technology Manufacturing and Assembly 
ABET BAND UNIT STANDARD TYPE PRE-2009 NQF LEVEL NQF LEVEL CREDITS
Undefined  Regular  Level 2  NQF Level 02  8 
REGISTRATION STATUS REGISTRATION START DATE REGISTRATION END DATE SAQA DECISION NUMBER
Passed the End Date -
Status was "Reregistered" 		 2007-09-18  2009-03-12  SAQA 0160/05 
LAST DATE FOR ENROLMENT LAST DATE FOR ACHIEVEMENT
2010-03-12   2013-03-12  

In all of the tables in this document, both the pre-2009 NQF Level and the NQF Level is shown. In the text (purpose statements, qualification rules, etc), any references to NQF Levels are to the pre-2009 levels unless specifically stated otherwise.  

This unit standard replaces: 
US ID Unit Standard Title Pre-2009 NQF Level NQF Level Credits Replacement Status
9411  Explain the operation of basic vapour compression refrigeration systems, and identify and explain the function of its components and accessories as well as their retrieval and storage procedures  Level 2  NQF Level 02  14   

This unit standard is replaced by: 
US ID Unit Standard Title Pre-2009 NQF Level NQF Level Credits Replacement Status
262177  Explain the basic vapour compression cycle, the components, the handing and storage of refrigerants  Level 2  NQF Level 02  8   

PURPOSE OF THE UNIT STANDARD 
Describe and explain how a refrigeration system transfers heat and identify and explain the function of its components and accessories. 

LEARNING ASSUMED TO BE IN PLACE AND RECOGNITION OF PRIOR LEARNING 
Ability to read and write. A basic knowledge of physics relating to heat and temperature 

UNIT STANDARD RANGE 
Refrigeration systems:
The single stage saturated refrigeration cycle.
System cooling air or water and rejecting heat via an air-cooled condenser, a water-cooled condenser and a cooling tower or an evaporative condenser.

Components:
The compressor, the expansion valve, evaporators cooling liquid or air, water and air-cooled condensers, the cooling tower and the evaporative condenser, fans, pumps, blower coils and fan-coil units.

Accessories:
Interconnecting piping, receivers, suction accumulators, vibration eliminators, crankcase heaters, sight glass/moisture indicators, service valves, shut-off valves, safety valves, Schraeder valves, charging valves, Schraeder valves, fusible plugs, filter-driers, burn-out kits, refrigerant strainers, mufflers, suction-liquid line heat exchangers, oil separators. 

Specific Outcomes and Assessment Criteria: 

SPECIFIC OUTCOME 1 
Explain, with the aid of a block diagram, the operation of the vapour compression refrigeration system. 

ASSESSMENT CRITERIA 

ASSESSMENT CRITERION 1 
Correct block diagrams of the vapour compression refrigeration systems are drawn. 

ASSESSMENT CRITERION 2 
The operation of a vapour compression system is explained. 

SPECIFIC OUTCOME 2 
Name and indicate the components and pipes in the block diagrams drawn and indicate the direction of flow of refrigerant and water. 

ASSESSMENT CRITERIA 

ASSESSMENT CRITERION 1 
Each component is indicated and named correctly. 

ASSESSMENT CRITERION 2 
Each pipe run is indicated and named correctly. 

ASSESSMENT CRITERION 3 
The direction of the flow of refrigerant, air and water is correctly indicated. 

SPECIFIC OUTCOME 3 
Explain the process taking place in each component. 

ASSESSMENT CRITERIA 

ASSESSMENT CRITERION 1 
The processes taking place in the components are explained correctly 

ASSESSMENT CRITERION 2 
The purpose of the condenser water pump, the chilled water pump and the spray water pump in the systems is explained correctly. 

ASSESSMENT CRITERION 3 
The phase and temperature of the refrigerant at the inlet and outlet of all components is stated correctly. 

ASSESSMENT CRITERION 4 
The temperature of the refrigerant and the water at the inlet and outlet of all the components is stated correctly. 

SPECIFIC OUTCOME 4 
Discuss the relationship between the pressure and the temperature of a refrigerant. 

ASSESSMENT CRITERIA 

ASSESSMENT CRITERION 1 
The relationship between the pressure and the temperature of refrigerants is correctly stated. 

ASSESSMENT CRITERION 2 
The fact that the gas increases in temperature when being compressed is stated. 

ASSESSMENT CRITERION 3 
The fact that evaporation and condensation of the refrigerant occur at constant temperature is stated and explained. 

SPECIFIC OUTCOME 5 
Identify and explain the function of components and accessories of a refrigeration system. 

ASSESSMENT CRITERIA 

ASSESSMENT CRITERION 1 
The various components and accessories of a refrigeration system are correctly identified and their position in a refrigeration plant is indicated. 

ASSESSMENT CRITERION 2 
The purpose of each component and accessory in the refrigeration system is explained. 

ASSESSMENT CRITERION 3 
The various types of components and accessories are listed. 

ASSESSMENT CRITERION 4 
The different makes and models of components and accessories are identified. 

SPECIFIC OUTCOME 6 
Handle and store refrigeration system components and accessories. 

ASSESSMENT CRITERIA 

ASSESSMENT CRITERION 1 
The handling and storage of refrigeration components and accessories in accordance with manufacturer's requirements is demonstrated. 

ASSESSMENT CRITERION 2 
The procedure for issuing components and accessories from and returning to stores is explained. 


UNIT STANDARD ACCREDITATION AND MODERATION OPTIONS 
Any person wishing to be assessed against this unit standard may apply to an assessment agency, assessor or provider institution accredited by the relevant ETQA, who may appoint a moderator to be present at the assessment.
The assessor must have knowledge and experience of air-conditioning and refrigeration 

UNIT STANDARD ESSENTIAL EMBEDDED KNOWLEDGE 
  • The basic processes involved in the vapour compression refrigeration cycle.
  • The various systems used and the role and application of refrigeration in daily life.
  • The function and operation of refrigeration components and accessories.
  • The handling, retrieval and storage of refrigeration system components and accessories.
  • Interpreting manufacturer's and/or work instructions or company guidelines regarding handling, retrieval and storage of refrigeration system components and accessories. 
    		•

    UNIT STANDARD DEVELOPMENTAL OUTCOME 
    N/A 

    UNIT STANDARD LINKAGES 
    N/A 


    Critical Cross-field Outcomes (CCFO): 

    UNIT STANDARD CCFO IDENTIFYING 
    Identify and solve problems
  • Identify refrigeration components and accessories 
    		•

    UNIT STANDARD CCFO WORKING 
    Work effectively with others
  • Assisting Level 3 Trade hand (Mechanic) by supplying correct accessory 
    		•

    UNIT STANDARD CCFO ORGANISING 
    Organize and manage myself and my activities responsibly and effectively
  • Selecting required component and accessory and retrieve from stores 
    		•

    UNIT STANDARD CCFO COMMUNICATING 
    Communicate effectively
  • By oral or written stores' order for component or accessory. Communicating with Level 3 Trade hand (Mechanic) 
    		•

    UNIT STANDARD CCFO SCIENCE 
    Use science and technology effectively and critically
  • By understanding the processes involved 
    		•

    UNIT STANDARD CCFO DEMONSTRATING 
    Demonstrate an understanding of the world as a set of related systems
  • Be aware of the effect of leakage of refrigerants on the environment 
    		•

    UNIT STANDARD CCFO CONTRIBUTING 
    Learner and societal development
  • By learning how a refrigeration system operates 
    		•

    UNIT STANDARD ASSESSOR CRITERIA 
    N/A 

    UNIT STANDARD NOTES 
    This unit standard has been replaced by unit standard 262177, which is "Explain the basic vapour compression cycle, the components, the handing and storage of refrigerants ", Level 2, 8 credits.

    This unit standard replaces unit standard, 9411, "Explain the operation of basic vapour compression refrigeration systems, and identify and explain the function of its components and accessories as well as their retrieval and storage procedures", Level 2, 14 credits.

    Supplementary information:
    The learner must show a basic understanding of the processes involved; for this he must be able to explain the processes in simple terms, the temperatures in terms of cold, warm or hot and the phase in terms of liquid or vapour or a mixture.

    Specific requirements are contained in one or more of the following documents:
  • Manufacturer's instructions regarding the handling of components and accessories.
  • Company procedures and guidelines regarding retrieval of components and accessories from stores. 
    		•

    QUALIFICATIONS UTILISING THIS UNIT STANDARD: 
      ID QUALIFICATION TITLE PRE-2009 NQF LEVEL NQF LEVEL STATUS END DATE PRIMARY OR DELEGATED QA FUNCTIONARY
    Core  48959   National Certificate: Air-conditioning, Refrigeration and Ventilation  Level 2  NQF Level 02  Passed the End Date -
    Status was "Reregistered"     		 2009-03-12  Was MERSETA until Last Date for Achievement 


    PROVIDERS CURRENTLY ACCREDITED TO OFFER THIS UNIT STANDARD: 
    This information shows the current accreditations (i.e. those not past their accreditation end dates), and is the most complete record available to SAQA as of today. Some Primary or Delegated Quality Assurance Functionaries have a lag in their recording systems for provider accreditation, in turn leading to a lag in notifying SAQA of all the providers that they have accredited to offer qualifications and unit standards, as well as any extensions to accreditation end dates. The relevant Primary or Delegated Quality Assurance Functionary should be notified if a record appears to be missing from here.
     
    NONE 


    All qualifications and part qualifications registered on the National Qualifications Framework are public property. Thus the only payment that can be made for them is for service and reproduction. It is illegal to sell this material for profit. If the material is reproduced or quoted, the South African Qualifications Authority (SAQA) should be acknowledged as the source.