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 THAT HAS PASSED THE END DATE: 

Compile and appraise control sequence diagrams for control systems as applied to air-conditioning, refrigeration or ventilation installations 
SAQA US ID UNIT STANDARD TITLE
9467  Compile and appraise control sequence diagrams for control systems as applied to air-conditioning, refrigeration or ventilation installations 
ORIGINATOR
SGB Air-conditioning Refrigeration and Ventilation 
PRIMARY OR DELEGATED QUALITY ASSURANCE FUNCTIONARY
-  
FIELD SUBFIELD
Field 06 - Manufacturing, Engineering and Technology Engineering and Related Design 
ABET BAND UNIT STANDARD TYPE PRE-2009 NQF LEVEL NQF LEVEL CREDITS
Undefined  Regular  Level 5  Level TBA: Pre-2009 was L5  6 
REGISTRATION STATUS REGISTRATION START DATE REGISTRATION END DATE SAQA DECISION NUMBER
Passed the End Date -
Status was "Registered" 		 2001-06-13  2004-06-13  SAQA 0836/01 
LAST DATE FOR ENROLMENT LAST DATE FOR ACHIEVEMENT
2005-06-13   2008-06-13  

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 
Compile and appraise control sequence diagrams for air-conditioning, refrigeration or ventilation installations and interpret these. 

LEARNING ASSUMED TO BE IN PLACE AND RECOGNITION OF PRIOR LEARNING 
  • Explain the operation of the vapour compression refrigeration cycle.
  • Interpret refrigeration and air-conditioning plant layout drawings and sketches.
  • Interpret electrical diagrams referring to air-conditioning and refrigeration installations.
  • Explain the function and operation of air-conditioning and refrigeration plants, components accessories, controls and control systems. 
    		•

    UNIT STANDARD RANGE 
    The control sequence diagram shall be for a plant where at least four of the following parameters are controlled: space or supply air temperature, relative humidity, air volume or air pressure including upper or lower limitations on these, chilled water temperature or water supply quantity. 

    Specific Outcomes and Assessment Criteria: 

    SPECIFIC OUTCOME 1 
    Prepare for compiling a control sequence diagram. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    1. The correct design or operating manual is consulted. 

    ASSESSMENT CRITERION 2 
    2. All control parameters and deviations tolerated are checked to conform to norms or specifications. 

    ASSESSMENT CRITERION 3 
    3. The sequence of events controlling the plant is determined correctly. 

    ASSESSMENT CRITERION 4 
    4. The operating parameters for the control instrumentation are determined correctly. 

    ASSESSMENT CRITERION 5 
    5. The mode of control for all parameters is determined correctly. 
    ASSESSMENT CRITERION RANGE 
    Direct acting and reverse acting modes.
     

    SPECIFIC OUTCOME 2 
    Compile the control sequence diagrams for individual control loops. 
    OUTCOME RANGE 
    Temperature, relative humidity, air volumes, pressures. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    1. The correct input and output values are selected. 

    ASSESSMENT CRITERION 2 
    2. The correct sensing, controlling and operating elements are selected. 

    ASSESSMENT CRITERION 3 
    3. The correct set points, deviations and/or proportional bands are selected. 

    ASSESSMENT CRITERION 4 
    4. The graphs are drawn correctly. 

    ASSESSMENT CRITERION 5 
    5. The functions of the controls are indicated correctly in the graphs. 

    ASSESSMENT CRITERION 6 
    6. All operating parameters are suitable for the application. 

    ASSESSMENT CRITERION 7 
    7. Control sequence diagrams for all loops are compiled. 

    SPECIFIC OUTCOME 3 
    Combine the individual control loops where required. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    1. Individual control loops are combined correctly. 

    ASSESSMENT CRITERION 2 
    2. System is checked to avoid overlaps. 

    SPECIFIC OUTCOME 4 
    Interpret a control sequence diagram. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    1. The interaction between different control parameters are stated and discussed. 

    ASSESSMENT CRITERION 2 
    2. The control sequence diagram is correctly interpreted. 


    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 or refrigeration. 

    UNIT STANDARD ESSENTIAL EMBEDDED KNOWLEDGE 
    Names and functions of control elements
    Norms for control set points and tolerances
    Principles of operation of the control modes used in air-conditioning and refrigeration
    Technical information on drawings
    Consequences of unsuitable control modes and/or methods 


    Critical Cross-field Outcomes (CCFO): 

    UNIT STANDARD CCFO IDENTIFYING 
    Identify and solve problems
  • Interpret technical specifications and operating or design manuals 
    		•

    UNIT STANDARD CCFO ORGANISING 
    Organize and manage myself and my activities
  • Prepare, plan and select information from drawings and manuals. 
    		•

    UNIT STANDARD CCFO COLLECTING 
    Collect, analyze, organize and critically evaluate information
  • Reading and interpreting instructions. 
    		•

    UNIT STANDARD CCFO SCIENCE 
    Use science and technology effectively and critically
  • Understanding the processes involved. 
    		•

    UNIT STANDARD NOTES 
    Control systems as applicable to commonly applied air-conditioning and refrigeration systems. 

    QUALIFICATIONS UTILISING THIS UNIT STANDARD: 
      ID QUALIFICATION TITLE PRE-2009 NQF LEVEL NQF LEVEL STATUS END DATE PRIMARY OR DELEGATED QA FUNCTIONARY
    Core  20722   National Diploma: Air Conditioning, Refrigeration and Ventilation  Level 5  Level TBA: Pre-2009 was L5  Passed the End Date -
    Status was "Registered"     		 2004-06-13  MERSETA 


    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.