Removing 1 of 2 covers above pump motor compartment, 1 hand on the side of cover, the other hand on 1 of the handles on top of cover. He pulled cover to him, lost his grip with his left hand, right hand was still in handle and twisted his arm. Released to go back to work next day. Primary doctor's opinion was he needed therapy and could return back to work 3/28/14 or sooner.