A reboiler in a tower is being hydrotested, the water should be at what level?

• A. At the level of the top of the reboiler
• B. Below the reboiler
• C. Above the reboiler
• D. At the bottom of the tower

Answer: (C)

Hydrostatic testing relies on a continuous column of water to apply uniform pressure and fully wet all surfaces being tested. Submerging the reboiler by keeping the water level above its top ensures every weld, joint, and internal passage is completely filled with liquid and exposed to the intended pressure. This eliminates air pockets that could mask leaks and guarantees the test pressure is applied across the entire surface. If the water level were only at or below the top, some areas might not experience the full test pressure, and hidden leaks could go undetected. Keeping the water level above the reboiler provides the necessary hydrostatic head to achieve a reliable test.