I have an Enviro Empress and it will start up and burn for a while but shut off and the middle heat light will blink. I have searched and it says it's a vacuum issue. The door seal seams to be not making a tight seal I put a dollar bill in it and closed it and it pulls out very easily. Also the ash pan gasket don't seem to be sealing good either. Is there an adjustment on thé door latch or does the gasket need to be replaced? Does anyone know the size of the door and ash pan gasket? I checked the tube running from the vacuum pump to the exhaust. Is there a way to test the pump itself?