the results are in

Mr. C's slow cooker heat experiment concluded yesterday and has resulted in the following information:  it's the recipe, not the cooker.  He did the high heat test on Thursday, the low heat test yesterday.  The water temperature rose to just where it should be.  So it was the recipe ~ cook chicken on low heat for 10 hours ~ that was at fault.  We should have known.  But at least I am relieved that we don't have to pack the machine up, send it back with a long, detailed explanation, and then wait for another one.  We're going to try another dish and use common sense about the cooking time.