When we bought out MH 1) I told the salesman that when we come back for the PDI that I wanted a Service Tech to go thru the PDI with me. He asked why and I asked him a couple of questions he couldn't answer, I then told him that's why. 2). I spent 3-4 days at home going over all the operator instructions and manuals and the unit. 3) I took a pre made PDI check list with me that I'd added questions to after going thru the manuals. Ever after spending 3-4hrs on the PDI the 1st couple of times we used the unit I was at a loss on how to do things.