SAQA 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.
SOUTH AFRICAN QUALIFICATIONS AUTHORITY 
REGISTERED UNIT STANDARD: 

Explain the function and operation of domestic refrigeration circuits and their components 
SAQA US ID UNIT STANDARD TITLE
123451  Explain the function and operation of domestic refrigeration circuits and their components 
ORIGINATOR
SGB Electrical Engineering & Construction 
PRIMARY OR DELEGATED QUALITY ASSURANCE FUNCTIONARY
-  
FIELD SUBFIELD
Field 12 - Physical Planning and Construction Electrical Infrastructure Construction 
ABET BAND UNIT STANDARD TYPE PRE-2009 NQF LEVEL NQF LEVEL CREDITS
Undefined  Regular  Level 4  NQF Level 04 
REGISTRATION STATUS REGISTRATION START DATE REGISTRATION END DATE SAQA DECISION NUMBER
Reregistered  2018-07-01  2023-06-30  SAQA 06120/18 
LAST DATE FOR ENROLMENT LAST DATE FOR ACHIEVEMENT
2024-06-30   2027-06-30  

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 does not replace any other unit standard and is not replaced by any other unit standard. 

PURPOSE OF THE UNIT STANDARD 
This unit standard is for persons in the electrical engineering field who will be required to maintain and repair refrigerated domestic appliances.

A person credited with this unit standard will be capable of:
  • Demonstrating and applying legislative requirements and standards applicable to maintain and repair domestic refrigerated appliances.
  • Demonstrating and explaining the function and principles of operation of various refrigeration system components and accessories.
  • Demonstrating the function and operation of various refrigeration system controls.
  • Demonstrating the evacuating and leak testing of a system.

    This unit standard will contribute to the full development of the learner within the electrical engineering field by providing recognition, further mobility and portability within the field of appliance repair. The skills knowledge and understanding demonstrated in this unit standard are essential for social and economic transformation and contribute to the upliftment and economic growth within the appliance repair environment. 

  • LEARNING ASSUMED TO BE IN PLACE AND RECOGNITION OF PRIOR LEARNING 
    It assumed that learners are competent in the following:
  • Communication at NQF Level 3.
  • Mathematical Literacy at NQF Level 3.
  • The operation of vapor compression refrigeration systems and refrigeration plant components and accessories. 

  • UNIT STANDARD RANGE 
    Air-cooled, water-cooled and evaporatively cooled DX and flooded systems as applied to air-conditioning or refrigeration systems. Direct and pilot operated controls, including crankcase pressure regulators, evaporator pressure regulators and condenser pressure control systems. Capacity control systems. Discharge by-pass valves, pressure relief valves, rupture discs, Electronic Expansion Valves. High side and low side float valves, poppet valves and orifices, compressors, evaporators, heat exchanges, fan, condenser, defrost heater, defrost systems, control systems, safety group. 

    Specific Outcomes and Assessment Criteria: 

    SPECIFIC OUTCOME 1 
    Explain the purpose and operation of a defrost system. 
    OUTCOME RANGE 
    Electric and hot gas defrost initiated by time, pressure or temperature. 

    ASSESSMENT CRITERIA
     

    ASSESSMENT CRITERION 1 
    The purpose of defrosting and defrost control is explained as per manufacturer's requirements. 

    ASSESSMENT CRITERION 2 
    The various methods of defrosting evaporator coils are stated and discussed in accordance with manufacturer specifications. 

    ASSESSMENT CRITERION 3 
    The equipment and controls and settings required for the various systems, their positions in the system are stated and their purpose is explained according to manufacturer standards and specifications. 

    ASSESSMENT CRITERION 4 
    The settings for the controls are stated and reasons for these settings are given with reference to manufacturer's requirements. 

    ASSESSMENT CRITERION 5 
    The operation of the defrost systems is checked against specifications or as per manufacturer's requirements and results are recorded and reported according to worksite procedures. 

    ASSESSMENT CRITERION 6 
    Safe working practices, which ensure personal, appliance and property safety, are demonstrated in accordance with legislative requirements and work site procedures. 

    SPECIFIC OUTCOME 2 
    Explain and demonstrate the function and principles of operation of various refrigeration system components and accessories in accordance with manufacturer's specifications. 

    ASSESSMENT CRITERIA
     

    ASSESSMENT CRITERION 1 
    The principles of operation of components and accessories as well as the internal and external factors influencing the operation are demonstrated in accordance with manufacturer's specifications. 

    ASSESSMENT CRITERION 2 
    System components and accessories are identified on an actual appliance and the purpose and use of each component is explained in accordance with manufacturer's specifications. 

    ASSESSMENT CRITERION 3 
    Advantages, limitations and common faults experienced with system components and accessories are discussed with reference to manufacturer's criteria and specifications. 

    ASSESSMENT CRITERION 4 
    The checks to be carried out before putting equipment into operation are demonstrated with reference to manufacturer's requirements. 

    ASSESSMENT CRITERION 5 
    The relevant maintenance requirements for the various system components and accessories are demonstrated practically. 

    ASSESSMENT CRITERION 6 
    Components and accessories at specific given operating conditions are selected from catalogues and tables. 

    ASSESSMENT CRITERION 7 
    Different makes and types of components and accessories are compared and contrasted and performance graphs of components, where applicable, are compiled from given data to establish performance across entire load spectrum. 

    SPECIFIC OUTCOME 3 
    Demonstrate the function and operation of various refrigeration system controls. 
    OUTCOME RANGE 
    Pressure, temperature. 

    ASSESSMENT CRITERIA
     

    ASSESSMENT CRITERION 1 
    The operation of various types of control are described, compared and contrasted for the various types of control methods used in refrigeration systems. 

    ASSESSMENT CRITERION 2 
    The purpose for using and the position in the system of the direct and pilot operated refrigerant control devices are stated and identified as per manufacturer's specifications. 

    ASSESSMENT CRITERION 3 
    The purpose and position of refrigerant relief devices are stated and identified as per manufacturer's requirements. 

    ASSESSMENT CRITERION 4 
    The factors to be considered when installing metering and control devices and methods are explained with reference to catalogues and tables given operating parameters. 

    ASSESSMENT CRITERION 5 
    The common faults that can occur with refrigeration systems controls and the consequences of selecting over or undersized controls are explained using practical examples. 

    SPECIFIC OUTCOME 4 
    Prepare and select components and accessories. 

    ASSESSMENT CRITERIA
     

    ASSESSMENT CRITERION 1 
    All the information to select the accessory or component is obtained and units / symbols are checked against manufacturer's and site conditions. 

    ASSESSMENT CRITERION 2 
    The information is checked against norms and the selection criteria for other components or accessories for the appliance. 

    ASSESSMENT CRITERION 3 
    Any special requirements related to make and model numbers are recorded in accordance with recording procedures. 

    SPECIFIC OUTCOME 5 
    Understand and explain how to Leak Test a system. 

    ASSESSMENT CRITERIA
     

    ASSESSMENT CRITERION 1 
    The different Leak Test methods are named and demonstrated in terms of Leak Test specifications. 

    ASSESSMENT CRITERION 2 
    The purposes of Leak Testing and the consequences of leaks in a system are demonstrated in accordance with Leak Testing specifications. 

    ASSESSMENT CRITERION 3 
    The equipment and instrumentation required for Leak Testing is selected and checked for suitability and safety. 

    ASSESSMENT CRITERION 4 
    The precautions to be taken when using nitrogen for pressurisation are explained in compliance with safety procedures. 

    ASSESSMENT CRITERION 5 
    The correct Leak Testing procedure and the methods to minimise the loss of refrigerant from a system through leaks are demonstrated in compliance with safety procedures. 

    SPECIFIC OUTCOME 6 
    Evacuate a system. 

    ASSESSMENT CRITERIA
     

    ASSESSMENT CRITERION 1 
    The reasons for evacuating a system before charging are named as per evacuation procedures. 

    ASSESSMENT CRITERION 2 
    The level to which the system is to be evacuated is stated and the reasons are demonstrated as per evacuation procedures. 

    ASSESSMENT CRITERION 3 
    The deep vacuum method and the triple evacuation method to remove moisture and non-condensables from a system are explained as per specifications. 

    ASSESSMENT CRITERION 4 
    The equipment and instrumentation required for evacuation are selected according to manufacturer's requirements. 

    ASSESSMENT CRITERION 5 
    All equipment and instrumentation are checked for suitability and safety and the procedure to evacuate a system is demonstrated in accordance with safety procedures. 

    ASSESSMENT CRITERION 6 
    The vacuum pump and instrumentation is removed from the system without the loss of vacuum and the system is isolated correctly. 


    UNIT STANDARD ACCREDITATION AND MODERATION OPTIONS 
  • Anyone assessing a learner against this unit standard must be registered as an assessor with the relevant ETQA.
  • Any provider offering learning that will enable achievement of this unit standard must be accredited as a provider through the relevant ETQA.
  • Moderation of assessment will be overseen by the relevant ETQA according to the moderation guidelines in the relevant qualification and the agreed ETQA procedures. 

  • UNIT STANDARD ESSENTIAL EMBEDDED KNOWLEDGE 
  • Names and functions of refrigeration plant components, accessories and controls.
  • Application and use of conversion factors and manufacturer's catalogues.
  • Consequences of selecting the incorrect components or accessories or mismatching these.
  • Theory of refrigeration as applied to domestic air-conditioning or refrigeration systems. 

  • UNIT STANDARD DEVELOPMENTAL OUTCOME 
    N/A 

    UNIT STANDARD LINKAGES 
    N/A 


    Critical Cross-field Outcomes (CCFO): 

    UNIT STANDARD CCFO IDENTIFYING 
    Identify and solve problems:
  • Selecting the correct components and accessories.
  • Interpret manufacturer`s catalogues. 

  • UNIT STANDARD CCFO ORGANISING 
    Organize and manage myself and my activities responsibly and effectively:
  • Select the correct manufacturer`s catalogues. 

  • UNIT STANDARD CCFO SCIENCE 
    Use science and technology effectively and critically:
  • By understanding the processes involved.
  • Identification of components and accessories.
  • Appropriate use of conversion factors. 

  • UNIT STANDARD ASSESSOR CRITERIA 
    N/A 

    REREGISTRATION HISTORY 
    As per the SAQA Board decision/s at that time, this unit standard was Reregistered in 2012; 2015. 

    UNIT STANDARD NOTES 
    Supplementary information:

    Specific requirements are contained in one or more of the following documents:
  • Manufacturer`s instructions.
  • Company procedures and guidelines. 

  • QUALIFICATIONS UTILISING THIS UNIT STANDARD: 
      ID QUALIFICATION TITLE PRE-2009 NQF LEVEL NQF LEVEL STATUS END DATE PRIMARY OR DELEGATED QA FUNCTIONARY
    Core  50371   Further Education and Training Certificate: Domestic Appliance Repair  Level 4  NQF Level 04  Reregistered  2023-06-30  EWSETA 


    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.