Dometic Toilet Problem

I will check these details later but I think the Dometic toilet was the CTW 4050 and the Thetford, the C263 - CSL.  I know the Dometic had the ceramic bowl - and that it used to stain far more quickly than a plastic one!

We also had the identical problem that you describe in that flush water leaked across the top of the blade and into the caravan - despite there being loads of silicone grease on it and me spraying it every two or three days.

The Thetford replacement looks as if it has a flush tank but in actual fact it's a dummy - but that's why it goes in without any signs of replacement.

The reason the dealer went for this model is that the filler cap / hole in the side of the van doesn't line up, so it's not possible to have a Thetford with the integral flush tank and, instead, the flush water is drawn from the inboard tank (as all our water is). Although I was a bit dubious about this, it's turned out to be a bonus and I prefer it. It just means you have a redundant filler cap on the side of the van but no one but you knows this!

Although it was an expensive fix and I wasn't best pleased having spent a shed load of money on a new 'flagship' German van, the problem is now sorted, once and for all. Why, given the high quality of everything else in the van, Knaus fit this (expensive) rubbish toilet, is beyond me (and the dealer agreed!).

Thanks for that.  I don't have an on board tank but in my last caravan, that had a Thetford toilet, I was able to access the flush tank from inside so that maybe a possibility.  You have certainly given me hope that there may be a real alternative to the Dometic, and a good pointer for further research 

As KjellNN has pointed out, it is apparently possible to fill the flush tank from the Aquaroll.  Failing that, a retro fit of an inboard tank is quite easy - ours was put in prior to purchase by the dealer since the Starclass 695, for some strange reason. is the only TA in the range without one.

I've just re read that post from KjellNN and can see that would work.  I'm a bit tight on payload so that would probably be my best option, I may even save some weight by replacing the ceramic with plastic.  The only issue I could have is the Thetford seems to come out further from the wall than my existing Dometic and it's cosy enough in the washroom as it is - a good excuse to visit a showroom or two and take some measurements - every cloud as they say 

Thank you very much for your help. 

I have exactly the same problem with the blade on my Dometic loo (2018). It works ok for a while after liberally spraying silicone over the slide rods and applying silicone grease to the seal, but it’s only a question of time before it becomes stiff again. The Thetford toilet in my previous MH had no such problems in 6 years of use and seemed a more robust construction.

Whitedragon - rest assured, it isn't deeper - and the reason I can be certain is that the carpet in ours fitted snugly around the base of the original Dometic and now there is a gap - at the front - of about an inch or so. Unless I pointed it out to you, you wouldn't notice - but it definitely isn't bigger.

The model number of the new Thetford is C263-CS

Hope this helps

Richard

Just read the problems with domestic toilets and would like to add our experience.We bought a new coachman VIP in February,not realising the troubles with these toilets.Our van is now parked up waiting for its 3rd visit to the dealers for toilet repairs.First time was to cure the toilet flushing on its own.Luckily we heard the pump running when we stopped.Went into the van to find bowl full and pump still running.Dealer fitted a new circuit board after having the van for 2 days.We also discovered that the cassette was leaking!

Next time we had been on site for a day when the pump started up on its own again.Not so lucky this time,the water overflowed on to the floor.Back to the dealer for 2 weeks this time.We were then told problem was with pink fluid blocking a breather pipe and we shouldn't use it.

3rd problem was when travelling back from a week away discovered the control panel on the top was falling into the housing of the toilet.

We cannot understand why coachman fitted these without testing them,have now been told they have gone back to Thetford for 2020.

Erny - sorry to hear this and, like me, you will be frustrated and angry that having shelled out a load of money, you are having these problems. One way or another, I would advise swapping it and if you can persuade the dealer to do it under warranty bearing in mind the Thetford is now fitted to 2020 models, so much the better. Virtually everything that could fail on ours - did - and I would never touch Dometic toilets with a barge pole ( or anything else for that matter!)

I’ve toyed with the idea of replacing our Dometic toilet with a Thetford one for some time now. Ours is fitted to a Burstner Ixeo motorhome and its the one item that spoils an otherwise perfect vehicle. I have to spray the slide with silicone after every empty and the flush mechanism’s performance has always been less than adequate. The design of the Dometic unit is abysmal. How it ever progressed passed the development stage has always been a mystery and an annoyance to me. Sounds like the Thetford loo is a viable alternative.

I would do it.  It's now five months since the toilet was changed and its had 60 days use since then without a single problem, whereas with the Dometic, something went wrong every time we were away. As I said earlier, the Dometic design is over-complicated and the materials used are flimsy.  I could have gone down the 'not fit for purpose' route but I suspect that wouldn't have got me anywhere other than putting my blood pressure up. At least it's sorted now.