Why do these tube bundles fail prematurely?

U tube bundle is normally a combination of three reasons. There is adverse temperature, adverse pressure or rust present. A number of the same reasons why HVAC heating coils neglect. It's normally an application where the originally chosen materials will not resist the responsibility and the machine features have changed over a long period of time thus causing premature failures.

Any tubing substance has a maximum working temperature and pressure evaluation. The issue sometimes is that the first equipment was selected at or very near the maximum score. Remember that maximum ratings are based on manufacturers one year warranty and have nothing to do with longevity. By selecting a cheaper casing and stainless tube bundle that's marginal for the application you may have issues in a brief period of time. Since a top quality choice should last twenty years or longer, when we create a poor selection we now begin seeing problems in three or four decades.