Got a red tag!
Did he say something was not up to code and needed to be changed immediately?
Did he say that it should have been noticed before (even though you have used the same company for many years and the code is not new)?
Did he say the heat exchanger was cracked and show you a picture from a camera or indicate with his finger a breech you could not possibly see, even with a magnifying glass?
Was a salesman calling ten minutes later who just happened to be in the neighborhood?
Does something smell fishy?