Dometic Loos?

[Guest Mel E]

Has anyone out there got any actual, practical experience of these loos? The are manufactured by a US company bought fairly recently by Dometic. They seem an interesting alternative to the standard Thetford Cassette loos. The loo is connected to its cassette by 1.5 inch plastic pipe and the loo emptied by a vaccum created by a pump in the casstte mounting. Thus: - the cassette can be put anywhere within 8 feet of the loo, so the loo doesn't have to be fitted to a wall with access for the cassette. - the cassette is completely sealed from the loo, so there is no need to use chemicals. - the loo has a ceramic bowl (rather than the scratchable plastic of Thetfords). Optionally, the system can be connected to a larger holding tank, complete with emptying pump. What I'd like to know is: 1. Does the loo bowl empty satisfactorily in practice - they claim the vacuum causes all solids to be broken down so they can pass through the 1.5 inch pipe without problems. 2. Is the cassette capacity adequate in practice - it is only 14 litres usable (because there has to be enough air space to create a workable vaccuum) but they claim the system uses much less flush water. H E L P ! !

[Guest Ruth]

Mel, I haven't any actual experience of them, so this may be unfair, but was talking to a manufacturer recently who was I believe the first to fit them to a British motorhome. He has now reverted to the Thetford, there were complaints of the debris getting stuck on the valve causing the motor to keep purring away,as it hadn't shut properly as a result. Rather a nuisance in the middle of the night. Apparently people also found them harder to clean as they are not boxed in, but I don't really get that as nor are all Thetfords. Also, he felt, the seat was about 1" too low and the seat was flimsier than he'd have liked. HTH Regards, Ruth

[Guest Derek Uzzell]

Mel: I've no practical experience of Dometic's toilet, but I also enquired about the adequacy of the 14 litre cassette when I visited the Dometic stand at the NEC show and was given the same answer (see also Response (12) to my toilet-related posting of 16/2). As I perceive it, Dometic's argument that their system uses less water is based on the premise that a Thetford toilet has a significant quantity of water introduced into the bowl prior to use and, subsequently, that the water and the waste it contains will be emptied into the cassette by opening the bowl-valve. This is, of course, one way to use a Thetford toilet and it will indeed use a fair amount of water, but it's not the method we adopt and I'm extremely doubtful that it's the technique most other people utilise either. We just open the bowl-valve before use, use the toilet, then rinse the bowl with as much water as necessary. So I'm certainly not convinced Dometic's system uses less water than Thetford 'Method B' and, as far as I'm concerned, the small capacity cassette is a definite drawback. Ruth's comment about debris getting stuck on the Dometic's 'flush ball' valve causes me no surprise: when I looked at the design I thought it pretty much inevitable that this would happen. I can see the appeal of Dometic's toilet when a large holding-tank is employed, as, unlike the traditional motorhome 'marine' implementation, the toilet pedestal does not need to be located directly above the tank. But I don't see this potential benefit transferring to the cassette version, nor am I attracted by the cost and complexity of the vacuum-system compared to the cheapness and simplicity of the Thetford product.