I just returned from Camping World and was told that the kitchen sink drain issues on my 2014 XLT 277RL has them baffled and that they have done all they can think of. The problem is only with the kitchen sink, the bathroom sink and shower work fine. They also told me that they are working with Heartland to warranty out the mechanical vent, which by the way was replaced last time. The vent has been removed and the water still will not go down which indicates that the problem is beyond the vent. It is very frustrating to have a 2 month old RV with this problem, by the way, we have taken it camping twice and had to return home with a clogged drain and the RV back at Camping World. Has anyone else had this experience and what was the final outcome?