A tough set of symptoms that make a diagnosis difficult. But you already knew that. We need Dr. House here.
I second all that Jay recommended. Also, the run-on pump can be a symptom of a failing diaphragm within the accumulator tank. You may need to check that too. (I'm not sure whether or not your Shurflow smart sensor pump is a VSD or not.)
A couple seasons ago I replaced my water pump (perfectly good) and accumulator tank (failed) with a new VSD pump that does not require an accumulator tank. We have been very happy for that change!
Last edited by wwilson; 08-21-2009 at 12:05 PM.