Leaking Thetford cassette toilet C260

The "experts" i think will advise to use with blade open as there is not a completely "watertight" seal between bowl and cassette 

I have the C260 and the orange handle (extendable) clicks firmly into place with no movement, and normally does not leak. However I also get very small leakage at times, this is cured on mine by removing the small limescale buildup on the underside of the bowl where the cassette seal rests.

Poke your head in and feel if there are any manufacture 'lumps' on the bottom of the bowl if you are certain limescale is not the cause.

On  a brand new van this is unacceptable IMO.

Bend your dealers ear.  This is not right.

Had the same problem on a new van fitted with a Dometic Toilet which, after a lot of cleaning up sessions(!) & experimenting with the blade open/closed, we were supplied with a new cassette unit. This cured the problem but as I was allowed to keep the old cassette, I decided to dismantle it and eventually found that the the blade unit which was locked into place using a 90' turn and a series of lugs was actually cracked underneath and despite the rubber seal, was allowing the liquid waste to leak out. Made worse of course with the weight of the user on the loo seat as well. Your blade set up my be different to this but could be worth checking..... we used to put plain water into the bowl and would observe what happened in the cassette compartment while ones partner sat on the loo and then watched what happened when the blade was opened. This should give you a few clues and fresh water is far more user friendly too !!! Also, make sure that the cassette is pushed fully 'home' as any misalignment can cause the problems you have had. Good luck

Is there any tell tale signs of leakage around the roof or sides of the housing or from the flush pipe area. If the van is level then I cant see how the leakage is from the cassette.

Check the flushing system. Take out the cassette and place a bucket under the flushing blade. Keep the blade closed at first and get someone to flush the bowl from the inside whilst you keep an eye for any leakage from inside the cassette chamber.

The blade is part of the cassette not the bowl assembly.

agree with CY. the cassette should be totally watertight in its own right...

however, if you are using the toilet with the blade closed (wrong IMV) and then opening it to allow waste into the cassette, you are relying on two things...

one, if the amount of 'waste' rises above the rim of the cassette, you are relying on the seal between the cassete and the bowl to prevent liquid seeping into the cassette compartment. as JVB says, this is NOT a watertight seal.

two, after use, you will then open the cassette where the blade will have to slide away to allow waste to fall into the bowl. without going into detail again, IMV, this is not a process i would want to happen...

far, far better, to open the blade, use the toilet (and let all waste go where it should, directly into the cassette) and then close the blade after use.

yes, there will be advocates of the 'toilet paper petal method' to tell you that you should use the toilet with the blade closed..... but we use the van loo for upto 30 weeks a year (dont use site toilets) and i speak with the experience of a 'regular' user....

good luck.

The only time we have had a leak is when a bit of toilet paper became stuck on the plastic lip, against which the cassette seals. Now I always check to see if this area is clear before reinserting the cassette. Ours makes a positive clunk as it goes into position and is firmly locked by the orange clip.

Yes agree with BB.  Regular use of Silicone Spray on Blade will help keep things moving ok

Thanks for all your replies! None of my previous Thetford loos have leaked. The dealer and Lunar are trying to fob me off that 'there's nothing wrong', as if we've imagined it, or are lieing. It's still with them, and I'm waiting for a phone call, but I imagine it will be me who calls. Nothing's changed in the 25 years or so I've been caravanning! It's definately leaking between the toilet bowl and the cassette seal - I've enclosed a pic to illustrate.