Kenmore Ac2044-1 electrostatic air cleaner...cleaned

Take a flash light to the filters to see if there is any debris. This helped me because as I was examining the cell for debris I noticed markings for "Top" and "Bottom" inscribed on the four corners of the front of the cell that I had never noticed before. After cleaning I had installed the cell upside down. It would work for 20 minutes and then shut off. The rounded thingies on the bottom of the cell are contacts which should touch the little springies on the bottom of the housing.

If the two filters have already been cleaned, and maintenance had recently been done by sears, then it is likely the control board.
The problem is that Sears does not distribute replacement parts for this particular appliance model. Therefore repair must be done at sears.