Oilers/Plant Tenders (HHC) Civil Service Practice Exam

What is the MOST important requirement of a refrigerator lubricant?

1. High viscosity

2. Freedom from water

3. Low freezing point

4. High flash point

The correct answer is: Freedom from water

The most important requirement of a refrigerator lubricant is its freedom from water. Water can cause significant damage to the refrigeration system, leading to corrosion of components, reduced efficiency, and the formation of ice that can obstruct the system. A lubricant that contains water would fail to adequately protect the moving parts, impair the lubrication process, and could negatively impact the overall operation of the refrigeration system. While high viscosity, low freezing point, and high flash point are relevant properties for a lubricant, they do not hold the same critical importance as being free from water. High viscosity is important for ensuring effective lubrication under specific operating conditions, but excessive viscosity can lead to inefficient pumping. Likewise, a low freezing point is useful to prevent the lubricant from solidifying in cold conditions, and a high flash point is vital to ensure safety by preventing flammability at high temperatures. However, the absence of water in the lubricant is paramount, as it directly affects the reliability and longevity of the refrigeration system.