Checked out Turbo Chef oven in last run lounge. Powered on unit and let heat, unit heated to set temp, after heating, display read f4 error, door switch display read close door when door was closed. Let unit cool, removed side panel. Checked switches, both are working properly. Adjusted switches so were aligned properly. Powered back on, unit heated to set temp. Ran product, product came out good, no errors. Opened and closed door numerous times, no errors. Unit is back in service.