Jeff Wisnia wrote:

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But, the thought of trying to find a section of pipe with significant
restriction caused by corrosion buildup poses an interesting
question.....
Anyone got any ideas on what principles of physics, thermodynamics or
maybe acoustics might be used to determine just where such a
restriction is located, assuming all the pipes are accessable, but without
disconnecting any of the plumbing?

Opening faucets in the sequence of their distance from the supply
point and noting the flow rates is too easy and answers along those lines
won't be accepted. G

Think angioplasty.