I had the dealer try to rectify the siphoning problem and they moved the end of the vent hose from hanging under the trailer to up on the side. Its better but it still isn't right. You'd think that FR has produced trailers long enough to know how to make one that doesn't drain out the water as you drive down the road!
I see the same issue in motorhome forums.
I called the dealer the other day and expressed my desire to have it resolved and they told me there is no fix they can do and that I should put some sort of valve on it that I open and close. Not so easy to do with a vent hose that I can't reach. Anyone know what valve they might be talking about? My best bet would be something right up at the vent, which is right next to the fill connection.
I told them that the vent hose obviously sticks too far into the tank because I can hear that it goes under water when the tank is only about 2/3-3/4 full. They said the hose can't be retracted from the tank. if I open up the underbelly do you guys think I can retract the vent hose from the tank, cut it, and reinsert? Or is it glued in or something? Surely the put the vent on top of the tank and not the side?