A reboiler in a tower is being hydrotested. The water should be at what level?

• A. At the top of the tower
• B. Below the re-boiler
• C. Above the re-boiler
• D. At the base of the tower

Answer: (C)

In hydrotesting a reboiler inside a tower, the goal is to fully submerge and pressurize the entire unit so any leaks or weak joints would show up. Filling water to a level above the reboiler ensures the shell and all connections are wetted and tested under pressure. If the water level were lower—below the reboiler, at the base, or only up to the top of the tower—air pockets or dry areas could remain, masking leaks and giving a false sense of integrity. Submerging the reboiler by keeping water level above it provides a true, reliable test of the equipment.