Symbol kitchen sink drain

We've been told to expect the waste water to drain very slowly from the kitchen sink in our 2015 model Symbol when we queried it. Has anyone else had this problem, is there a solution? It speeds up if we plunge it.

Waste water can drain v slowly on both caravans and motorhomes, usually due to a tortuous route for the waste pipe to the tank/outlet. 

You often find that one set of wastes, say shower and washbasin drain immediately because their route to the outlet is very direct, whereas the waste from the kitchen is usually on the opposite side of the van and tends to run parallel to the floor for some distance, which doesn't help drainage. Sometimes if you get under and strap up the bend as it reaches underfloor level it will improve matters.

It will speed up if you plunger it but that's because you're putting additional pressure on it and you're risking a wastepipe joint blowing and a waste water leak.

Ah! Thanks for that. Looks as though we're just going to have to be patient. Just checking the info we were given was correct. We will leave the plunger at home!

Thanks. Will give that a try. It's our first campervan so it's all new to us!

We have the seemingly slow drain from the kitchen sink. Thinking that a blockage of some sort left by previous owner, did improve a little by pouring hot water with soda crystal (powder form) down plughole. However found the exact reason being that the waste pipe runs some distance parallel to the floor. So if the van is parked nose down even ever so slightly, then the waste will be draining up hill.....glug glug glug.

Plungering  it with the palm of your hand is another way to get it moving, that usually causes a vortex as well.

Thanks for the advice we'll try your suggestions

The kitchen sink on our 2009 Symbol has invariably been slow to drain and we're fastidious about preventing fat and solids like rice grains & coffee grounds going down.  It's never caused a problem or blocked completely.  The diameter of the waster pipe is a lot smaller than at home so that's a big factor in the slower draining.

Thanks. We did think the small pipe wouldn't help - just wanted to check it out with the experts on the forum. Nothing beats experience!