RACA Journal June 2016 - Page 72

Back to Basics manually removed from the system via the oil drain pot. Oil is not a refrigerant and will cause problems on the cooling process. This oil will be contaminated and it is not a good procedure to reuse the oil in the system. As the level rises and falls in the suction accumulator, the feed solenoid will open and close, allowing liquid to flow from the high pressure side of the system to the suction accumulator. It is most important to understand the correct operation of plant valves during servicing as failure to do so could lead to a hydraulic isolation of parts of the system, and the risk of system failure. Ammonia has an extremely high coefficient of expansion. Due to the high internal pressures that could result when trapped liquid evaporates, special care must be taken during maintenance. 70 RACA Journal I June 2016 Each component in the refrigeration system has a specific task to perform, which is an essential part of the overall operation. The definition and description of each item is self-explanatory and relates specifically to the task that these items undertake. Without the correct selection of these components it will not be possible for the refrigeration system to function as intended. I have two very bright sons who work for Star Refrigeration in London. I asked one of them what the most important part of a refrigeration system was and, in his opinion, it was the refrigerant. In reality, every piece of equipment is important but we must not lose sight of what the cooling process is all about. Remember: in order to cool the space/medium, we need to start at the point in the system where we collect the heat – the evaporator. RACA www.hvacronline.co.za