Refrigeration & Air-conditioning Technician

Transcription

1 Refrigeration & Air-conditioning Technician A competent Refrigeration & Air-conditioning Technician is expected to: 1. Make use of best practice principles based on theory and experience gained throughout training and work experience. 2. Be able to plan and execute work in a safe and responsible manner. 3. Understand the nature of a problem and seeking help through text, individuals or any other method as deemed necessary. 4. Be able to collect and present data in an easily understood manner, and to analyse said data in order to remedy or predict situations which may arise. 5. Have the techniques of communicating information, ideas, problems and solutions with his clients, management, colleagues and other persons he may be leading. 6. Be able to compile technical reports and hand-over documentation. 7. Have expertise in the correct and safe use of general engineering hand tools, portable power-tools, general and specific testing equipment and other related accessories when working on refrigeration & A/C plant & machinery. 8. Have knowledge of the basic scientific & engineering principles of the operation and behaviour of the plant, machinery and other elements pertaining to his trade/profession and to their application.

2 The candidate applying to be trade tested for the Certificate of Competence should be in possession of the majority of the following knowledge, competencies & skills: Technical report writing both on daily basis and full report writing with respect to more intensive interventions. Proper technical verbal communication with particular reference to technical fault description and plant layout and construction, operations and maintenance. General fault finding of domestic, commercial & industrial Refrigeration & A/C plant & equipment and associated ditribution systems. Routine maintenance (Mechanical & Electrical) of typical Refrigeration & A/C plant including individual equipment, components and systems. Sourcing information from technical manuals and literature and identifying components which may need to be procured. Hands on experience in the repairs & installation of mechanical engineering techniques in executing pipework, in metal joining methods (welding, brazing, etc) and knowledge of valves, pumps & various components and plant items commonly found on refrigeration installations. Hands on experience in the testing and handling Electrical circuitry and motors.the interpretation of circuit diagrams with a view to fault finding in single & three phase circuits. The safe use of electrical test instruments and tools. General Health and Safety practices and principles. Be aware of the proper personal protective equipment (PPE) needed in each particular situation. Refrigeration systems of various types and sizes as employed in domestic, commercial and Industrial applications. Refrigeration Compressors. Various types of Refrigeration compressors, construction, their advantages, disadvantages and uses.their operation and suitability for different applications with different Refrigerants. Multi compressor systems, packaged Units. Types of compressors, reciprocating, centrifugal, rotary, single and twin sc rewand othersrew,uses etc. Evaporators & coolers. Types, including shell and tube, baudelot, cooling media. Their construction and application. Defrost systems. Condenser: Types, including shell & tube, evaporative, use of different media including air and water, and operating through different methods, forced and induced draught etc. Refrigerant metering, the expansion valve and other metering devices. Control devices, manual valves, solenoid valves, capacity control mechanisms, etc. Monitoring components, gauges, sight glasses. Refrigerant Oils, Chacteristics, compatibility, uses, entrainment, cooling, separation etc. System evacuation, charging, leak detection methods, purging, pumping down, charging,evacuation and other procedures particular to the trade. Other auxiliary equipmentand components forming part of the refrigerant cycle. The absorption refrigeration cycle. Uses of refrigeration: Refrigerated storage.refrigeration in transport. Refrigeration in processing of foodsand beaverages etc.

3 Refrigerants: Characteristics of refrigerants. Their choice for differnt duties. Their suitability and handling under differnt work environments. Considerations of their effects on system safety and efficiency. The effect of Refrigeration on the environment, Climate Change (Global warming), TEWI, REAL ZERO, F Gas regulations. Renewable energy enhancements to the refrigeration cycle (Solar, Geothermal etc.) Air Conditioning The understanding and use of Psychrometry & the psychrometric chart. The conditioning of air spaces through the use of suitably sized and chosen equipment for the particular uses and environments. Cooling, Heating & ventilation requirements of different ambients based on different parameters as use, occupation, regulatory air changes etc. The choice of equipment, its suitability for the job in hand, its installation requiremets together with knowledgeof the reqiured upkeep and maintenance. Knowledge of types of plant components and A/C equipment, their characteristics, advantages and disavantages and their application. Such plant and components to include : Chilled water producers (Chillers), Reverse cycle heating, Boilers (for space heating), Auxiliaries such as types of condensers, heat exchangers, Fans, Air handling Units, Air filters, Buffer tanks, types of pumps and water circulation systems, dehumidifiers, humidifiers, calorifiers,dampers, valves and other controls, instruments & gauges. General piping systems of different materials and other fluid distribution methods such as ducting in different materials, shapes, their support stuctures, jointing methods and systems, insulation and its characteristics for different applications etc. Insulation and relative materials. Basic thermodynamic principles. Practical operation. Identification of the main components. Logging and interpreting system data in order to diagnose a faulty system. Typical maintenance interventions: oil replacement, seal replacement, filter replacement etc. Inspection and servicing of the critical components. Proper and safe use of common and special toolsand test equipment for the trade. Safety procedures and the use of proper safety protectiveclothing and whilst working on any equipment.

4 Overhaul of components such as intake and exhaust valves, lubricating system including bearings, water cooled heat exchangers etc). Proper and safe use of common and special tools when working on refrigeration systems. Safety procedures to be adopted when working on air conditioning and refrigeration systems. Water circulation systems including hot water, pumps, valves and distribution systems Basic thermodynamic principles Practical operation Identification of the main components of equipment and systems. Logging and interpreting system data in order to diagnose a faulty system. Scheduled maintenance activities related to a fluid power system (e.g. replacement/adjustment of gland, lip and mechanical seals, cleaning/replacement of strainers, greasing, oil changing). Overhaul of components such as bearings, impellers, shafts, seals, couplings and motor alignment procedures. Overhaul of a boiler system, calorifier, burners, electrodes etc. Proper and safe use of common and special tools when working on fluid power systems. Safety procedures to be adopted when working on fluid power systems. Electrical circuitry, controls, Motors and other Ancillary equipment Basic knowledge of electrical circutry and electrical Motors. Fundamental operating principles with reference to electric motor starting techniques. Basic fault finding related to generators and electric motors. Interpretation of recorded/reported system data for fault identification. Proper and safe use of common and special tools when working electrical equipment. Safety procedures to be adopted when working on electrical equipment.

5 ASSESSMENT CRITERIA Trade Testing Board Assessment Criteria 1. Introduction The following is a detailed description of the assessment criteria to be adopted by the Trade Testing Board (TTB) to reach a final decision on the award of a Certificate of Competence 2. Trade Test The trade test is to be made up of the following four components: 1. The Written 2. The Practical 3. The Interview

6 The Board has agreed on the sequence of the test and the markings allocated to each specific component as indicated below: Component Mark Pass Mark Written % Interview % Practical %

7 The Written Component The theory test paper will include theoretical and practical questions covered by the subjects and topics listed above. The Interview Component All candidates shall be called to attend an interview during which the Board will assess the proficiency and competence of the candidate related to the field of Refrigeration and Air Conditioning. The duration of the interview will be circa 20 minutes. The candidate will be assessed on the following criteria:- Attitude and aptitude. Practical work experience and knowledge. Technical questions related to Refrigeration & Air Conditioning engineering Comprehension of basic engineering principles related to Refrigeration & air Conditioning plant & equipment. Ability to elaborate in their field of expertise. The Board expects the candidate to answer questions with confidence in a technical manner showing knowledge of the subject. The Board will issue a mark accordingly.

8 The Practical Component The typical method the Board may choose to adopt is an on-site visit to a well equipped plant room. The board will individually asses the candidate from a practical side by presenting several common situations and asking the candidate on the possible best approach to take. The engineering system/s chosen shall pertain to the chosen trade and shall also include general engineering practices of maintenance, plant description and identification etc. The board expects candidates to hold a good conversation and answer questions put forward in a detailed technical manner thus showing indepth understanding of the practical principles of the above systems.