When an exchanger tube is plugged, why is the tube cut before the second plug is installed?

• A. To prevent pressure build up
• B. To ensure a tight seal
• C. To prevent corrosion
• D. To fit more easily

Answer: (A)

Relieving any trapped pressure before securing the second plug is the key idea. When you’ve already driven one plug into the exchanger tube, the interior between the two plugs can still be under process pressure. If the second plug is installed while that pressure is still present, it can push against the plug or prevent a tight seal, creating a safety and leakage risk. Cutting the tube provides a controlled way to vent or relieve that pressure so the second plug can be seated safely and seal properly. This is why the tube is cut first. It isn’t about fitting more easily or preventing corrosion; it’s about avoiding pressure buildup that could compromise the plugs.