mine wouldnt vent and the dealer removed the obstruction in my vent line by blowing into it.they also took a saw and cut my underbelly almost all the way accross !!!!!they then taped it up,which lasted untill right after they went out of bussiness!!!!now i get to retape it semi monthly or whatever.it was under warranty at the time but now i have a unsecure underbelly .i didnt notice this untill tape let go a year later,i also wonder what the obstruction was that they blew back into the freshwater tank ,and when it will plug intake and drain.buckeyebob