Why Should Tubes Be Cleaned Before Testing?
Every tubed vessel requires the surface of the tubes to be clean and scale-free to function efficiently and to ensure accurate testing when searching for tube leaks.
If the tube is not cleaned before testing for leaks, tube leaks may not be detected. If any residue is left in the tube it can trigger a false negative or false positive result when testing.
False negatives can occur if tube holes are covered by deposits. When the test gun is inserted into the tube and pressure is maintained, debris can be forced inside of a leak path, thus disguising the presence of a leak. This can cause issues later on once the debris is dislodged and the tube continues to leak. False positive readings can also occur if tubes are not properly cleaned. If debris or excess lubricant is present in the ID of the tube it can cause the seal to slip and not expand properly. Without proper seal expansion, the test gun would show a false positive result, resulting in tubes being plugged unnecessarily.
Another issue that can occur due to debris has to do with the tester itself. Vacuum tube testers have a screen inside the venturi nozzle. This screen can become clogged from the deposit and debris inside the tube. The clogged screen will not allow air to pass across the venturi nozzle, which in turn will not allow the test gun to create a sufficient vacuum in the tube. It can allow small particles to pass through and collect on the check valve, preventing it from operating properly. If the check valve does not work, it will allow air to pass into the tube, resulting in a false reading (a leak will be indicated where in fact there is no leak).
Overall, it is important that tubes are properly cleaned prior to testing for leaks. If tubes are not clean, it can result in false readings and potentially increase maintenance costs later on. Visit our tube cleaning section for more information about tube cleaners and how to choose the right one for your application.