Had my camper for just over a year now, and throughout that time the waste water drainage has been very sluggish. I took it back to seller and asked for advice, they simply replaced the drainage tap (the other one was covered in duct tape lol) but didn't really say anything re slow drainage. It literally just dribbles out. Often sink wont empty either, to the extent I now avoid using it without basin which I will empty down toilet (which of course means that needs emptying sooner!) The shower and bathroom sink drains into the waste tank well enough. I have tried usual solutions - vinegar, baking soda and cheap cola but to no avail. Anyone any suggestions please?
Our old Bailey 745 had a similar problem with the original fit, honestly I could widdle better than the waste water would come out of the waste pipe.
I had the dealer replace the original fit (which IIRC was about 20mm diameter), for an Autotrail fit which was much wider, it drained much quicker after that.
With respect to your sink, take a look at the flexi waste hose, it may be too long and the pipe has formed a u-bend which is preventing it draining freely.
Ours got very sluggish. I put several dissolved dish washer tabs down the sink when the tank was as empty as it was going to get, before driving to the next site. Brown gunk did come out at the next site, but still no enthusiasm; so I put my little finger up at the exit end & out came something like a huge slug & masses of waste water. It wasn’t a slug, just gunk, but the waste pipe now skooshes out at full force. Ok, a bendy wire would have been more pleasant but I didn’t have one.
if the drain pipes are corrugated, get them replaced for smooth pipe. Also check if the tank can vent air out as the waste water goes in, this is normally through other drains, but if the plugs are in or closed, the air can't escape as the waste goes in, this could also be the problem when emptying the waste tank air cant move into the tank so you get a partial vacuum making it difficult for the waste to leave.
------------- Regards
Johno
VP and Librarian of the Renault Trafic MK1 Owners group
Try pouring some hot water with mixed with some good old washing up liquid down the drain hole then use a rubber plunger over the sink plug hole. Where there are 'U' bends in the waste pipe which there quite often is then the pressure will dislodge any build up of gunge. If it's severe then apply a dose of waste pipe and drain unblocker if the first application fails to work effectively.