To test the alarm on a wet pipe system with an alarm valve, what should the inspector open?

When testing an alarm on a wet pipe system with an alarm valve, opening the alarm bypass is the appropriate action. The alarm bypass is specifically designed for testing purposes without affecting the overall functionality of the sprinkler system. By opening this bypass, you can allow water to flow through the alarm system to ensure that the alarm is activated correctly, and you can verify that the alarm is functioning properly without disrupting the entire system.

The other options do not serve this testing function effectively. Opening the main valve can disrupt water flow to the sprinklers and affect the system's performance, while opening the drain valve could lead to losing water from the system instead of testing it. The inspection port allows for visual inspection and may provide access to check for obstructions or issues within the piping but does not facilitate the necessary flow of water required to test the alarm function. Therefore, using the alarm bypass is the most effective and informed choice for testing the alarm in a wet pipe system.