As a heating service technician, there is one thing above all that we must be and that is our professional. We are being invited into someone's home to perform a service. We will be judged by the client on how efficient and professional we are. We must always remember that we are representing the company. The impression that our leave with the client will either help to grow the business or could help to cause it to fail. As a HVAC professional, we will be called on to service all type of HVAC systems. Some of these installations will be net some will be old. We need to understand how to service and maintain many different types of HVAC systems from many manufacturers. We need to remember that when we are dealing with old systems, we must always perform the special checks of the system to make sure that the system is safe to operate. We are the front line of defense for the client to make sure that his or her system will operate in a safe mode all winter long. We also must be able to efficiently troubleshoot and repair any problem that comes up. One of the most important parts of the job of HVAC professional is knowing what to look for when we receive a call from a home-owner that his or her gas heating system, as an example, is in need of repair. We must listen to the homeowner carefully, because he or she is our most valuable source of information. It is our job to be able to ask the proper questions that will lead us to the correct diagnosis of the problem. In order to become an effective troubleshooter, a firm understanding of basic refrigeration and electrical concepts must be established before wiring diagrams can be interpreted or refrigeration system problems can be diagnosed.