Which port is used to indicate an O-ring damage?

• A. Port B
• B. Port D
• C. Port A
• D. Port C

Answer: (B)

Detecting O-ring damage relies on monitoring the port that communicates with the O-ring seal area. When an O-ring is damaged, the seal cavity is a likely path for leaking fluid or gas, so the indicator port that provides an outlet from that gland or seal region will show leakage or a pressure change. That specific port is the one designed to reveal a compromised seal, which is why it is the best choice. The other ports are used for supply, exhaust, or measurements unrelated to the leak path around the O-ring, so they wouldn’t reliably indicate O-ring damage.