This unit involves the skills and knowledge required to diagnose and rectify faults in complex air conditioning/refrigeration systems.

It includes working safely, interpreting technical data and applying knowledge of complex refrigeration/air conditioning system operating parameters to logical fault-finding processes. It also includes implementing fault rectification, safety and functional testing, and completing and reporting fault diagnosis and rectification activities and outcomes.

To undertake this unit, the learner must have a Trainee Refrigerant Handling Licence as it includes work on refrigeration and air conditioning equipment that carries the risk of a fluorocarbon refrigerant being emitted.

The skills and knowledge described in this unit require a national Refrigerant Handling Licence as it includes work on refrigeration and air conditioning equipment that carries the risk of a fluorocarbon refrigerant being emitted while decanting the refrigerant or manufacturing, installing, commissioning, servicing, maintaining or decommissioning refrigeration and air conditioning equipment.

The skills and knowledge described in this unit require a licence or permit to practice in the workplace where work is carried out on electrical installations which are designed to operate at voltages greater than 50 volt (V) alternating current (a.c.) or 120 V direct current (d.c.).

Competency development activities in this unit are subject to regulations directly related to licensing. Where a licence or permit to practice is not held, skills and knowledge described in this unit require a relevant contract of training, such as an Australian Apprenticeship.

Additional and/or other conditions may apply in some jurisdictions subject to regulations related to refrigeration, air conditioning or electrical work. Practice in the workplace and during training is also subject to work health and safety (WHS)/occupational health and safety (OHS) regulations.

Permits may also be required for some work environments, such as confined spaces, working aloft, near live electrical apparatus and site rehabilitation.

ELEMENTS

PERFORMANCE CRITERIA

Elements describe the essential outcomes.

Performance criteria describe the performance needed to demonstrate achievement of the element.

1

Prepare to diagnose and rectify faults

1.1

WHS/OHS requirements and procedures are identified, obtained and implemented

1.2

WHS/OHS risk control measures and procedures are followed in preparation for work

1.3

Hazards are monitored and any not previously identified are documented and risk control measures implemented in consultation with relevant person/s

1.4

The extent of faults are determined from reports/documentation and discussions with relevant person/s

1.5

Relevant person/s is consulted to ensure work is coordinated with others on the worksite

1.6

Tools, equipment and testing devices required to diagnose faults are obtained and checked for correct operation and safety in accordance with workplace procedures

2

Diagnose and rectify faults

2.1

WHS/OHS risk control measures and workplace procedures for carrying out the work are followed

2.2

Need to test or measure live work is determined in accordance with workplace procedures and WHS/OHS requirements

2.3

Circuits/machines/plant are checked as being isolated, where necessary, in accordance with workplace procedures and WHS/OHS requirements

2.4

Logical diagnostic methods, measurements and estimations are applied to diagnose complex refrigeration/air conditioning system faults in accordance with system operational parameters and requirements

2.5

Suspected fault sources are tested to confirm if they are the source of system problems

2.6

Fault causes are identified and appropriately competent person/s engaged to rectify the fault where it is outside the scope of the refrigeration and air conditioning system

2.7

Faults in system components are rectified to return refrigeration/air conditioning system to its operational standard

2.8

System is tested to verify that the system operates as intended and to specified requirements and industry standards

2.9

Methods for resolving unexpected situations are discussed, as required, with appropriate person/s in accordance with job specifications and requirements

2.10

Methods for resolving unexpected situations are selected on the basis of safety and specified work outcomes

2.11

Diagnosis and rectification activities are conducted without waste of materials, damage to apparatus, the surrounding environment and/or services using sustainable energy practices

3

Complete and report fault diagnosis and rectification activities

3.1

WHS/OHS work completion risk control measures and procedures are followed

3.2

Worksite is made safe in accordance with workplace safety procedures

3.3

Fault diagnosis and rectification activities are documented in accordance with workplace procedures

3.4

Appropriate person/s is notified that system faults have been rectified in accordance with workplace procedures

Evidence required to demonstrate competence in this unit must be relevant to and satisfy all of the requirements of the elements, performance criteria and range of conditions on at least one occasion and include:

applying logical diagnostic methods

using fault scenarios to test the cause of system faults

identifying faults and competency needed to rectify them

rectifying faults in system controls

verifying that the system operates correctly

dealing with unplanned events

applying relevant legislations, industry standards, codes of practice and regulations

applying relevant work health and safety (WHS)/occupational health and safety (WHS/OHS) requirements, including:

applying safe working practices

hazard identification and reporting

implementing risk control measures

completing and reporting fault diagnosis and rectification activities

determining need to test or measure live work

isolating circuits/machines/plant

using relevant tools, equipment and testing devices.

Evidence required to demonstrate competence in this unit must be relevant to and satisfy all of the requirements of the elements, performance criteria and range of conditions and include knowledge of:

complex refrigeration and air conditioning system fault finding and repair, safe working practices and relevant standards, codes and regulations, including:

fault-finding techniques including:

factors to consider in clarifying the nature of a fault:

initial fault report

confirmation of symptoms of the fault

comparison of symptoms with normal operation

effect to cause reasoning — assumptions of possible causes

methods for testing assumptions encompassing:

visual inspection

sectional testing

split-half tests

component isolation

dealing with intermittent faults

causes of intermittent faults are vibration, shock, changes in temperature and electromagnetic interference

refrigeration system analysis, including:

pressure enthalpy definitions:

high pressure and low-pressure refrigerants

triple point of new refrigerants

glide of trinary blends

differential evaporation of refrigerant blends

variable refrigerant volume

refrigeration cycle, including:

expansion process

vaporising process

compression process

condensing process

compression ratio

enthalpy processes, including:

co-efficient of performance

effect of suction temperature on cycle efficiency

effect of condensing temperature on cycle efficiency

actual refrigerating cycles, including:

design operating conditions

effects of superheating suction vapour

superheating without useful cooling

superheating that produces useful cooling

superheating in suction piping outside the refrigerated space

superheating the vapour inside the refrigerated space

effects of subcooling the liquid

effects liquid - suction heat exchangers

effects of pressure losses resulting from friction

refrigeration cycle faults, including:

symptoms and causes

measurements and fault confirmation tests

air conditioning system analysis, including:

psychrometric chart, including:

properties, definitions and units

plotting conditions:

RA, SA, OA and MA

psychometric processes, including:

heating

cooling only

cooling and dehumidification

cooling, dehumidification and reheat

design operating conditions, including:

indoor and outdoor wet and dry bulb temperatures

volume flow rate supply, return and outdoor air

air conditioning system faults, including:

symptoms and causes

measurements and fault confirmation tests

power and control system analysis, including:

power and control circuit diagrams

sequence of operation

manufacturers diagrams, specifications and instructions

power and control circuit faults:

symptoms and causes

measurements and fault confirmation tests

relevant measurements and estimations

relevant risk mitigation processes

relevant WHS/OHS legislated requirements, including:

environmental and sustainable energy principles and practices

safe working practices

relevant workplace policies and procedures

relevant workplace documentation.

Assessors must hold credentials specified within the Standards for Registered Training Organisations current at the time of assessment.

Assessment must satisfy the Principles of Assessment and Rules of Evidence and all regulatory requirements included within the Standards for Registered Training Organisations current at the time of assessment.

Assessment must occur in workplace operational situations where it is appropriate to do so; where this is not appropriate, assessment must occur in simulated workplace operational situations that replicate workplace conditions.

Assessment processes and techniques must be appropriate to the language, literacy and numeracy requirements of the work being performed and the needs of the candidate.

Resources for assessment must include access to:

a range of relevant exercises, case studies and/or other simulations

relevant and appropriate materials, tools, equipment and personal protective equipment (PPE) currently used in industry

applicable documentation, including workplace procedures, equipment specifications, regulations, codes of practice and operation manuals.

Foundation skills essential to performance are explicit in the performance criteria of this unit of competency.

Range is restricted to essential operating conditions and any other variables essential to the work environment.

Non-essential conditions may be found in the UEE Electrotechnology Training Package Companion Volume Implementation Guide.

Diagnosing and rectifying faults must include at least four faults in the following complex refrigeration/air conditioning systems:

multiple major components (i.e. compressors, condenser or evaporators)

circuits or systems and associated components and controls

Electrotechnology

Refrigeration and air-conditioning