Which device is essential when pressurizing nitrogen for a leak test on copper tubing?

• A. Vacuum pump
• B. Regulator
• C. Thermometer
• D. Manometer

Answer: (B)

Controlling the test pressure is essential when pressurizing copper tubing with nitrogen to check for leaks. A regulator does exactly that: it takes the high pressure from the nitrogen cylinder and lowers it to a safe, steady level while maintaining that set pressure throughout the test. This stable pressure is what lets you reliably observe any drop that would indicate a leak, without risking damage from over-pressurization or fluctuations.

Using a vacuum pump would pull air out, creating a low-pressure condition rather than a controlled positive pressure needed for a leak test. A thermometer measures temperature, which isn’t what’s needed to detect leaks. A manometer can show the pressure level, but it doesn’t control or regulate the pressure itself; you’d still rely on the regulator to keep the test pressure constant.