Where would wet instrument air first show up in an instrument loop?

The correct answer is that wet instrument air would first show up at the dryer. The function of the dryer in an instrument air system is to remove moisture from the compressed air before it is sent through the rest of the instrument loop. If the air is not properly dried, the moisture would be present at the dryer as it processes the air.

When wet air comes into the system, the dryer is the first component it encounters that addresses the issue of moisture. Properly functioning dryers are crucial, as wet air can lead to issues such as corrosion, freezing, and malfunction of sensitive instrumentation that relies on dry air to operate effectively.

While the air piping, fitting regulator, and valve positioner are all parts of the instrument loop, they would typically not encounter wet instrument air first; those components rely on processed and dried air. The dryer is specifically designed to handle and mitigate the presence of moisture, making it the initial location where wet air would manifest in the system.