This unit involves the skills and knowledge required to determine operating conditions of vapour compression system.It includes working safely; determining refrigerant pressures and temperatures, and relevant air and water temperatures using measurement and calculation methods. It also includes working with the three states of matter at each point in the refrigeration cycle (liquid, vapour and liquid-vapour mixture).The skills and knowledgein this unit will be applied by refrigeration and air conditioning technicians during the commissioning, service and repair of refrigeration and air conditioning systems.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 may, in some jurisdictions, also require a licence or permit to practice in the workplace subject to regulations for undertaking refrigeration and air conditioning work. Practice in the workplace and during training is also subject to work health and safety (WHS)/occupational health and safety (OHS) regulations.