Drainage from Topaz washroom basin

Water is very slow to drain away,  the Dealer says it is because the pipes go uphill or there is an air lock.  I am not convinced as surely the weight of water higher up would push it down, there must be a pressure vent for the waste tank to allow water to flow in freely.  Also there is no problem from the kitchen sink or it's associated drip drain.

I have disconnected the pipe under the basin and pushed a pipe brush on a 1 metre flexible spring into the pipe and brought out a lot of black gunge.  I also tried a 1 and half metre flexible spring and snagged some pale gunge.

I have today sucked out liquid and poured in about 75ml of strong caustic drain unblocker (that filled the pipe up to the base of the trough) but after half an hour although the level had gone down the pipe was not clear as it soon filled up again.  I have now had a second go and am leaving that overnight.

I'd be glad to know if anyone else has had these problems.  The van is 14 years old so I guess previous owners have not cleaned the pipework properly.

Hey up
Is it a tip up sink as our talisman sink is and it drained slow. After investigating and pouring allsorts down it I eventually pulled the surround off to find a block of wood and the plug in the drain pipe needless to say it drains a treat now

Thanks for your reply, I'll bear that in mind if my present efforts do not work.  I have had the basin off and checked the plug hole, also the hose.  In the morning I'll see if I can get more than 1 litre to drain away.

I have now used strong drain unblocker, disconnected the pipe from the plastic unit and used a 1.5 meter flexible brush to remove black gunge.  The drainage was a bit better, I could pour 1 litre down before it showed in the trough.  The Dealer has now used a high pressure hose on both ends and the water now gurgles away very quickly then builds up to sit in the trough.  The Dealers now say there is nothing more they can do, it must be an air lock.

Now initially the water runs away very quickly (better than I have ever seen it) but then backs up into the trough and gradually seeps away.  The grey tank is not full and also I have tried with the drainage tap open.

Having looked at the pipework under the van I see it is made up of several pieces with rigid inserts to connect the flexible pipe, which obviously restricts the flow and also gives interior shoulders for stuff to catch on.  Is this how it was originally fitted or could some previous owner have just replaced part of the pipework instead of renewing the whole length.  If it should be one length of pipe I can probably get the Dealer to replace the pipe.  (At 77 it is not a task I would like to try).  

Hi there
I've had a number of T4 Topazs and not experienced the problems you are having. It should drain away quickly. If mine, I would certainly replace the complete waste pipe from basin  to the tank as it sounds like it is breaking down. This is the only way to be sure.  I can't remember if there were any/many joins. Hope you can get your dealer to sort it. 
Regards
John

Thanks for your comments.  It's good to know you have not had problems, all good info to give to the Dealer. I do know someone with a younger Topaz and am trying to get in touch to see if that one has a single piece drainage pipe.  I need all the info I can get before returning yet again to the Dealer, as he is convinced nothing can be done.  Ann

Hi folks,  Symbol but the units are the same.

Last week we went to Wales in the rain but I digress when we arrived the floor of the washroom was covered in a white gunge and at first I could not find where it was coming from. I spoke to the wife and she could not throw any light on it. I then removed the sink and found that a bar of soap from last year had fallen off the soap tray and made its way into the channel behind the sink, needless to say it blocked the channel and filled it with soapy gunge. I cleared it out and no problem with the drainage now.  

The moral of this story is keep the soap bar away from the soap tray and store it in a container of better still use liquid soap.

Best Regards, Mike    

Hi Mike,  What a horrible mess to find!  We found problems with the soap sliding off the ledge and have decided to fit a wall mounted soap dispenser for general handwashing and will keep the soap bar in a container.  As my sister (Songbird) and I only got the Topaz in February we are gradually finding improvements to make, the problem is finding the time to carry them out . Ann