When first inspecting a hermetic system known to be leaking, you should look for:

• A. Visible signs of oil residue around joints and fittings
• B. Presence of water droplets inside the system
• C. Crystallization on the exterior surfaces
• D. Unusual color changes in the refrigerant

Answer: (A)

Verified step by step guidance

1. Understand that a hermetic system is designed to be sealed and leak-free, so any leaks can often be detected by physical signs around the system's joints and fittings.
2. Recognize that oil is commonly used in refrigeration systems as a lubricant, and if the system leaks, oil can escape and leave visible residues near the leak points.
3. Note that water droplets inside the system or crystallization on exterior surfaces are less direct indicators of leaks and may be caused by other factors such as condensation or environmental conditions.
4. Consider that unusual color changes in the refrigerant are not typically visible or reliable indicators of leaks in a hermetic system.
5. Therefore, the most practical and immediate sign to inspect for when checking a leaking hermetic system is the presence of visible oil residue around joints and fittings.