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

Select control systems and instruments for air conditioning, refrigeration and ventilation plants, determine control parameters and draw control sequence and electrical wiring diagrams 
SAQA US ID UNIT STANDARD TITLE
116458  Select control systems and instruments for air conditioning, refrigeration and ventilation plants, determine control parameters and draw control sequence and electrical wiring diagrams 
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 4  NQF Level 04  7 
REGISTRATION STATUS REGISTRATION START DATE REGISTRATION END DATE SAQA DECISION NUMBER
Passed the End Date -
Status was "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 
Learners competent in this unit standard will be able to select the most suitable control system and/or instrumentation to regulate, and/or improve, and/or protect the operation of air conditioning or refrigeration systems, determine the control parameters and produce control sequence diagrams, wiring diagrams and specifications. 

LEARNING ASSUMED TO BE IN PLACE AND RECOGNITION OF PRIOR LEARNING 
  • The identification, operation and commissioning of ON-OFF and modulating control systems.
  • Electrical safety 
    		•

    UNIT STANDARD RANGE 
    Types of control systems:
    ON-OFF, floating control, proportional (P), proportional and integral (PI) and proportional, integral and derivative (PID) control, fuzzy control.
    Control parameters:
    Accuracy of control, control limits, alarms, indications, records, BMS control.
    Types of control instruments:
    Operational controls, safety controls and efficiency controls.
    Operational controls.
    Thermostats, humidistats, pressure stats.
    Temperature, enthalpy, humidity, pressure and velocity sensors.
    Safety controls:
    Overheating stats, humidity stats, pressure switches, flow switches, interlocks.
    Efficiency controls:
    Compressor condenser pressure controls, superheat and de-superheat controls, economy cycle based on temperature and enthalpy. 

    Specific Outcomes and Assessment Criteria: 

    SPECIFIC OUTCOME 1 
    List, explain and discuss the principles of the different types of modulating control systems. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    The operating principles of the various modulating control systems are discussed. 

    ASSESSMENT CRITERION 2 
    The parameters to be controlled are listed and explained. 

    ASSESSMENT CRITERION 3 
    The types of control instruments used are listed and discussed. 

    ASSESSMENT CRITERION 4 
    The commonly used operational control instruments are listed. 

    ASSESSMENT CRITERION 5 
    The commonly used safety control instruments are listed. 

    ASSESSMENT CRITERION 6 
    The commonly used efficiency control instruments are listed. 

    SPECIFIC OUTCOME 2 
    Interpret the operation of the plant to be controlled. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    The operating parameters for the plant to be controlled are correctly interpreted. 

    ASSESSMENT CRITERION 2 
    The unloading characteristics of the system are determined. 

    ASSESSMENT CRITERION 3 
    The control parameters for the system are determined or obtained. 

    ASSESSMENT CRITERION 4 
    Various control systems are considered. 

    ASSESSMENT CRITERION 5 
    The suitability of the control system for the plant is considered and discussed. 

    SPECIFIC OUTCOME 3 
    Select an appropriate control system. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    Different control systems are considered and evaluated. 

    ASSESSMENT CRITERION 2 
    Reasons for the selection are stated and explained. 

    ASSESSMENT CRITERION 3 
    Advantages and disadvantages of the system are listed and discussed. 

    ASSESSMENT CRITERION 4 
    Consequences of selecting an inappropriate system are listed and discussed. 

    SPECIFIC OUTCOME 4 
    Determine the control parameters for all control instruments. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    The control parameters for all the instruments are determined. 

    ASSESSMENT CRITERION 2 
    Additional features required for all control instruments are determined. 

    ASSESSMENT CRITERION 3 
    Consequences of selecting incorrect parameters are discussed. 

    SPECIFIC OUTCOME 5 
    Select the control instruments. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    All the required control instruments are listed. 

    ASSESSMENT CRITERION 2 
    Reasons for selecting the instruments are listed and discussed. 

    ASSESSMENT CRITERION 3 
    The ranges of the selected instruments are stated and discussed. 

    ASSESSMENT CRITERION 4 
    The consequences of selecting unsuitable control instruments are listed and discussed. 

    SPECIFIC OUTCOME 6 
    Draw the control sequence diagram. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    The control sequence for the systems is determined. 

    ASSESSMENT CRITERION 2 
    The control sequence diagram is drawn. 

    ASSESSMENT CRITERION 3 
    The operation of the control system is interpreted and explained. 

    SPECIFIC OUTCOME 7 
    Draw the wiring diagram for the plant. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    The wiring diagram systems is determined. 

    ASSESSMENT CRITERION 2 
    The wiring diagram is drawn. 

    ASSESSMENT CRITERION 3 
    All loads are determined. 

    ASSESSMENT CRITERION 4 
    All interlocks and delays are determined. 

    ASSESSMENT CRITERION 5 
    The wiring diagram is in accordance with the SI system. 

    ASSESSMENT CRITERION 6 
    The operation of the system is interpreted and explained. 

    SPECIFIC OUTCOME 8 
    Write the specification for the control system. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    The specification for the control system is written. 

    ASSESSMENT CRITERION 2 
    The specification is complete and provides all information. 


    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 
  • The need for control and the determination of the required environmental and operational conditions to provide the required conditions in an air conditioned or refrigerated space.
  • The advantages and disadvantages of various types of controls and control systems.
  • The relationship between plant capacity supply and demand side in order to select the correct control instrumentation or system.
  • Matching control systems to the air conditioning or refrigeration system.
  • Writing of control specifications and drawing control sequence and wiring diagrams. 
    		•

    UNIT STANDARD DEVELOPMENTAL OUTCOME 
    N/A 

    UNIT STANDARD LINKAGES 
    N/A 


    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:
  • The learner does not require knowledge to design an air-conditioning system but will be required to match the control system to capabilities of the air conditioning or refrigeration system
    (i.e. unloading possibilities and accuracy of control required.) 
    		•

    QUALIFICATIONS UTILISING THIS UNIT STANDARD: 
      ID QUALIFICATION TITLE PRE-2009 NQF LEVEL NQF LEVEL STATUS END DATE PRIMARY OR DELEGATED QA FUNCTIONARY
    Core  48966   Further Education and Training Certificate: Air-conditioning, Refrigeration and Ventilation  Level 4  NQF Level 04  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.