I'm not going to say that the tech didn't go over that, but it may be that he thought that because of our experience with other 5v'ers we knew about such things. (There is just the slightest chance that I forgot about this part also
)
Last year our neighbor in Florida voiced a wish that his Montana 3850FL had a black tank flush like most other RV's. I casually mentioned that I would install it for the meager fee of $50. He asked if we could do it before he and DW left for the season and I said no problem. I walked him around to the street side, opened the service panel and pointed out the connection. As I held my hand out for the fifty he just belly-laughed and remarked that in four years he never new about the rinse. And no, he never parted with the $50.