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

Identify and set ON-OFF control devices as used in air conditioning and refrigeration systems, explain their operation and discuss their application and fault finding 
SAQA US ID UNIT STANDARD TITLE
116226  Identify and set ON-OFF control devices as used in air conditioning and refrigeration systems, explain their operation and discuss their application and fault finding 
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  6 
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 
To enable the learner to identify the ON-OFF controls used in air conditioning systems, describe their purpose and function, connect them to the system and set them in operation. 

LEARNING ASSUMED TO BE IN PLACE AND RECOGNITION OF PRIOR LEARNING 
  • Use of hand tools
  • Identify electrical cables.
  • Explain the basic refrigeration cycle.
  • Explain the purpose of air conditioning and describe the operation of unitary types of air conditioners. 
    		•

    UNIT STANDARD RANGE 
    Types of control systems:
    On-Off controls, Closed loop systems and open loop systems.
    Terms:
    Control system, sensor, measuring element, controller, actuator, ON-OFF control action, controlled variable, set point, control point, deviation, differential, accuracy, sensitivity, dead zone or dead band, cycling, hunting, automatic reset, manual reset, set high, set low, interlock, time delay, delay off, delay on.
    Types of control devices:
    Operational controls, safety controls and efficiency controls.
    Energy sources for control systems:
    Self contained control systems, electric control systems and electronic control systems.
    Operational controls.
    Thermostats, hygrostats, pressure switches.
    Safety controls:
    Overheating stats, humidity stats, pressure switches, flow switches, interlocks, time delays.
    Efficiency controls.
    Head pressure controls.
    Types of measuring elements (sensors)., controllers and actuators :
    Bi-metal element, the bulb and capillary sensor and the electronic type sensor.
    Types of controllers:
    Electric and electronic.
    Types of actuators :
    Relays, contactors, valve actuators and damper motors 

    Specific Outcomes and Assessment Criteria: 

    SPECIFIC OUTCOME 1 
    Define the terms used to describe an ON-OFF control system and its functions. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    A control system is defined and its main parts are named. 

    ASSESSMENT CRITERION 2 
    The types of control systems are stated and described. 

    ASSESSMENT CRITERION 3 
    Terms used to describe the function and operation of a control system are listed and discussed. 

    ASSESSMENT CRITERION 4 
    The commonly used variables that are controlled in an air conditioning system are listed. 

    ASSESSMENT CRITERION 5 
    The commonly used variables that are controlled in a refrigeration system are listed. 

    SPECIFIC OUTCOME 2 
    State and describe the commonly used control systems based on their energy source. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    The three energy sources used for control systems are listed and described. 

    ASSESSMENT CRITERION 2 
    The advantages and disadvantages of the three energy sources are listed. 

    SPECIFIC OUTCOME 3 
    State and describe the three types of control devices used on air conditioning and refrigeration systems. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    The three types of control devices used on air conditioning and refrigeration systems are stated. 

    ASSESSMENT CRITERION 2 
    The purpose of the different types of control devices is stated. 

    ASSESSMENT CRITERION 3 
    Examples of these types of devices are listed and discussed. 

    SPECIFIC OUTCOME 4 
    State and describe the commonly used types of measuring elements and sensors. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    The types of measuring elements and sensors used are listed and described. 

    ASSESSMENT CRITERION 2 
    Typical applications of these measuring elements and sensors are named. 

    ASSESSMENT CRITERION 3 
    The advantages and disadvantages of the different types are listed. 

    SPECIFIC OUTCOME 5 
    Connect and commission ON-OFF control devices. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    The control devices are correctly connected. 

    ASSESSMENT CRITERION 2 
    The control devices are correctly set to stated parameters. 

    ASSESSMENT CRITERION 3 
    Operation of the control devices is checked. 

    ASSESSMENT CRITERION 4 
    Possible malfunctions are listed and discussed. 


    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 identification, purpose and function of ON-OFF controls, their operation, adjusting and commissioning. 

    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:
    Only knowledge of the purpose and operation of the controls is required. The learner does not require knowledge to select the controls. 

    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 
    Core  65489   National Certificate: Air-Conditioning, Refrigeration and Ventilation  Level 3  NQF Level 03  Passed the End Date -
    Status was "Reregistered"     		 2023-06-30  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.