[77newell]

I used to work as an engineer in a chemical plant. We had lots of heat exchangers. Failures at the tube sheet to tube interface were usually caused by stresses due to thermal expansion and contraction being too rigidly restrained. On our CACs and RADs if the ends are solidly fastened (restrained), then as the units heat up the expansion has only one way to resolve itself - by flexing the tube sheet on the ends or by flexing the tubes. Particularly with materials that work harden - copper and aluminum - they will eventually crack. If this is where our leaks are occurring then we really would benefit from creating a more forgiving mounting.

A Google search identified some rubber bushing being used to mount CACs. I'll see if I can get some pictures in the next week of how large trucks are mounting things.