Husband bought me a Round "doughnut shape" dehydrator from outdoor sportman catalog many many moons ago. Rarely ever used it since there was no manual or brand name to guide me. This one at the following link has the lid top with adjustable "vent dial" exactly like mine. http://www.sausagemaker.com/32215fooddehydrator.aspx I have brought the dehydrator out of the catacombs and am determined to use it for my sun dried tomatoes (San marzano's)-of which I have about 25 lbs. It has a fan on the bottom and I have about 20 trays- not that I use all of them at once but have them. There is a vent dial on top and I have not a clue how to use it for drying effect. Do I leave it all the way open? part way? or close it shut? It takes almost 24 hours to get just 1 tray worth dried when I used just 1 tray of the small tomatoes-cut in half and seed removed (which I did save for next year crop :cowboy Not sure wat position I put the dial on though... So any tips on using this thing?