AURETU004
Diagnose and repair air conditioning and HVAC systems


Application

This unit describes the performance outcomes required to diagnose and repair faults in the air conditioning systems, including heating, ventilation and air conditioning (HVAC) systems, fitted to a range of vehicles and machinery for passenger convenience and comfort. It involves preparing for the task, selecting the correct diagnostic procedure, carrying out the diagnosis and the repair, performing post-repair testing, and completing workplace processes and documentation.

It applies to those working in an automotive service and repair industry. Automotive air conditioners, including HVAC systems, include those in agricultural machinery, heavy commercial vehicles, light vehicles or mobile plant machinery.

Licensing requirements apply to this unit. Users are advised to check with relevant regulatory authority.


Elements and Performance Criteria

Elements

Elements describe the essential outcomes.

Performance Criteria

Performance criteria describe the performance needed to demonstrate achievement of the element. Where bold and italicised text is used, further information is detailed in the range of conditions section.

1. Prepare to diagnose and repair air conditioning and HVAC system

1.1 Job requirements are determined from workplace instructions

1.2 Diagnostic information is sourced and interpreted

1.3 Diagnostic options are analysed and those most appropriate to the circumstances are selected

1.4 Hazards associated with the work are identified and risks are managed

1.5 Diagnostic tools and equipment are selected and checked for serviceability

2. Diagnose air conditioning and HVAC system

2.1 Diagnostic tests are carried out according to workplace proceduresand safety and environmental requirements using appropriate tools and techniques without causing damage to components or system

2.2 Faultsare identified from diagnostic test results and causes of faults are determined

2.3 Diagnosis findings and recommendations for necessary repairs or adjustments are reported according to workplace procedures

3. Repair air conditioning and HVAC system

3.1 Repair information is sourced and interpreted

3.2 Repair options are analysed and those most appropriate to the circumstances are selected

3.3 Repair tools, equipment and materials are selected and checked according to manufacturer specifications and workplace procedures

3.4 Repairs and component replacements and adjustments are carried out according to requirements, and without causing damage to components or systems

3.5 System is recharged with the appropriate refrigerant gas according to manufacturer specifications and workplace procedures

3.6 Post-repair testing is carried out according to workplace procedures to confirm fault rectification, and any further problems detected as having been introduced during the repair process are rectified

4. Complete work processes

4.1 Final inspection is made to ensure work is to workplace expectations and the vehicle or machinery is presented ready for use

4.2 Work area is cleaned, waste and non-recyclable materials are disposed of, and recyclable material is collected

4.3 Tools and equipment are checked and stored and faulty electrical equipment is identified, tagged and isolated according to workplace procedures

4.4 Australian Refrigeration Council accredited service decal sticker (ARCtick) and other required workplace documentation are completed and processed according to workplace procedures

Evidence of Performance

Before competency can be determined, individuals must demonstrate they can perform the following according to the standard defined in the unit’s elements and performance criteria, range of conditions and foundation skills:

diagnose and repair a fault in the air conditioning and heating, ventilation and cooling (HVAC) systems of two different vehicles or machinery, in which the work must involve removing, refitting or replacing two of the following:

condenser

evaporator

expansion valve

compressor

heater box.


Evidence of Knowledge

Individuals must be able to demonstrate knowledge of:

work health and safety (WHS) and occupational health and safety (OHS) requirements relating to diagnosing and repairing air conditioning and HVAC systems, including procedures for:

working with refrigerants at boiling point given risk of frostbite

working with system lubricants, including carcinogenic oils

handling flammable refrigerants

using personal protective equipment (PPE)

identifying and using fire safety equipment

environmental requirements, including procedures for preventing loss of refrigerant to the atmosphere

key requirements relevant to diagnosing and repairing air conditioning and HVAC systems detailed in the Australian automotive code of practice: Control of refrigerant gases during manufacture, installation, servicing or de-commissioning of motor vehicle air conditioners

air conditioning and HVAC system principles, including:

heat transfer principles, including convection, conduction and radiation

functions of the following air conditioning components:

compressor

condenser

receiver-drier

evaporator

blower fan

refrigerant

functions of the following heating components:

radiator

thermostat

radiator and heater hoses

heater tap

heater box

single zone and multi-zone vehicle layouts

application, purpose and operation of air conditioning and HVAC systems and components, including:

high pressure and low pressure sides of air conditioning systems

compressors, including:

axial type, including variable capacity compressors

scroll type

vane type

electromagnetic clutches

condensers

receiver-dryer, including filters and desiccants

expansion valves, including capillary tube

evaporator

thermostat

refrigerants, including R12, R134, R1234yf and hydrocarbon refrigerants

compressor oils

air conditioner and heating controls, including levers and ducting

air conditioner and heating electrical circuits and sensors, including:

high and low pressure switches

pressure relief valves

temperature sensors

climate control systems

diagnostic testing procedures for air conditioning and HVAC systems, including:

using diagnostic flow charts

using manifold gauges on systems with different refrigerants, including analysis of high and low pressure readings in conjunction with temperature probes

testing electrical systems, including procedures for:

accessing electrical terminals and using test probes without damaging connectors, fuse holders or wiring

resistance and voltage drop tests

open and short circuit tests

checking shorts to signal, power circuits and grounds

repair procedures for air conditioning and HVAC systems, including procedures for:

using manifold gauges to discharge, evacuate and charge system refrigerants

removing and replacing system components

post-repair testing procedures for air conditioning and HVAC systems, including procedures for checking for:

refrigerant leaks

heater core and system water coolant leaks

static and dynamic performance tests of air conditioning and HVAC systems, including checking:

ambient temperature

vent temperature

condenser and suction line temperature.


Assessment Conditions

Assessors must satisfy NVR/AQTF assessor requirements and hold an Australian Refrigerant Council (ARC) Refrigerant Handling licence.

Competency is to be assessed in the workplace or a simulated environment that accurately reflects performance in a real workplace setting.

Assessment must include direct observation of tasks.

Where assessment of competency includes third-party evidence, individuals must provide evidence that links them to the air conditioning and HVAC systems that they have worked on, e.g. repair orders.

Assessors must verify performance evidence through questioning on skills and knowledge to ensure correct interpretation and application.

The following resources must be made available:

automotive repair workplace or simulated workplace

workplace instructions

manufacturer specifications for air conditioning and HVAC systems

Australian automotive code of practice: Control of refrigerant gases during manufacture, installation, servicing or de-commissioning of motor vehicle air conditioners

ARCtick service decal stickers

procedures for servicing and adjusting vehicle air conditioning and HVAC systems

two different vehicles or machinery with air conditioning and HVAC system faults

diagnosis and repair equipment for air conditioning and HVAC systems, including:

manifold and gauge set

recovery unit

vacuum pump

electronic leak detector

nitrogen cylinder and regulator

multimeter

electronic scales

oil injector

infra-red thermometer

temperature probe

scan tool.


Foundation Skills

This section describes those language, literacy, numeracy and employment skills that are essential to performance and are not explicit in the performance criteria.

Skills

Description

Learning skills to:

identify and locate various sources of information efficiently.

Reading skills to:

interpret text, symbols and wiring diagrams relating to diagnostic and repair information from manufacturer specifications and workplace instructions and procedures

interpret requirements relevant to diagnosing and repairing air conditioning and HVAC systems of the Australian automotive code of practice.

Writing skills to:

legibly and accurately fill out workplace documentation, including ARCtick stickers, when reporting diagnostic findings, making repair recommendations, and recording parts and material used.

Oral communication skills to:

clarify instructions

report diagnostic findings and make repair recommendations.

Numeracy skills to:

match refrigerant types and identification numbers to workplace instructions, parts lists, manufacturer specifications, code of practice and regulatory requirements

interpret weight measurements, including tare and gross weights

interpret readings on pressure gauges

measure temperatures and pressures and use basic mathematical operations, including addition and subtraction, to calculate deviations from manufacturer specifications.

Planning and organising skills to:

plan own work requirements and prioritise actions to achieve required outcomes and ensure tasks are completed within workplace timeframes.

Technology skills to:

use specialised equipment, including refrigerant vacuum recovery equipment and manifold gauges.


Range Statement

This section specifies work environments and conditions that may affect performance. Essential operating conditions that may be present (depending on the work situation, needs of the candidate, accessibility of the item, and local industry and regional contexts) are included. Bold italicised wording, if used in the performance criteria, is detailed below.

Safety and environmental requirements must include:

work health and safety (WHS) and occupational health and safety (OHS) requirements, including procedures for:

working with refrigerants at boiling point given risk of frostbite

working with system lubricants, including carcinogenic oils

handling flammable refrigerants

using personal protective equipment (PPE)

identifying and using fire safety equipment

environmental requirements, including procedures for preventing loss of refrigerant to the atmosphere.

Repairs and component replacement and adjustment requirements must include:

manufacturer specifications

workplace procedures

Australian automotive code of practice: Control of refrigerant gases during manufacture, installation, servicing or de-commissioning of motor vehicle air conditioners.

Post-repair testing must include:

validating the effectiveness of the repair action by checking the following:

ambient temperature

centre vent temperature

condenser and suction line temperature

manifold gauge pressure readings

refrigerant leaks

heater core and system water coolant leaks.

Australian Refrigeration Council accredited (ARCtick) service decal sticker information must include:

name of the service organisation

name of technician

Refrigerant Handling Licence Number

vehicle registration number

service date

refrigerant type

lubricant type.


Sectors

Technical - Air Conditioning and HVAC


Competency Field

Electrical