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Thetford c400 toilet vent


DavieR

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Hi folks, my first post here.

 

We have a Thetford C400 toilet with a c402 cassette in our new campervan. We have had a VW camper for 17 years but this is our first time with an onboard loo.

 

I understand that the cassette has a vent to release gas build up and this exits on the underside of the cassette. There are two small compartments in the floor of the unit, one of which is for storage. As far as I can see there is no through the floor vent fitted and my question is whether this is correct or not? Venting gas to the cassette compartment seem odd to me and potentially smelly!

 

Thanks

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Welcome Davie R

 

As far as I am aware the over or under pressure device is on the top of the cassette.

 

It prevents a vacuum being created when you go from sea level to a higher altitude or vice versa. In normal circumstances the pressure within the cassette will be equalised every time you open the blade.

 

We had a problem with a new van when the venting system failed to work. On reaching the top of a mountain we were unable to open the cassette blade. Solution was to loosen the filler cap and a woosh of air equalised the pressure within the cassette. The blade could then be opened.

 

Removed the venting valve, gave it a clean and no further problems.

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Thanks Robbo.

 

Maybe I 'm getting confused by the SOG system for the C400. It vents the cassette from the cassette bottom and, via the filter, out through the floor.

 

We will see how we get on this weekend.

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DavieR - 2017-05-16 6:29 PM

 

Hi folks, my first post here.

 

We have a Thetford C400 toilet with a c402 cassette in our new campervan. We have had a VW camper for 17 years but this is our first time with an onboard loo.

 

I understand that the cassette has a vent to release gas build up and this exits on the underside of the cassette. There are two small compartments in the floor of the unit, one of which is for storage. As far as I can see there is no through the floor vent fitted and my question is whether this is correct or not? Venting gas to the cassette compartment seem odd to me and potentially smelly!

 

Thanks

 

The locker into which a Thetford C400’s toilet-cassette is inserted will normally (as you’ve rightly said) have two removable-lidded compartments in its floor, with the compartment nearest the locker’s door designed to store small containers of toilet chemicals. (Photo attached)

 

As you’ve also correctly said, when the cassette is slid into the locker a fitting on the cassette’s underside engages with a circular fitting (visible in photo) on the top of the lid of the rear compartment and this engagement opens a pressure-release valve within the cassette.

 

What you’ve asked is whether there ought to be some means of venting to the outside air gasses emerging from the cassette and passing into the locker’s rear compartment.

 

My Rapido motorhome has a Thetford C403 toilet and Rapido has fitted an ordinary wash-basin waste-outlet into the floor of the locker’s rear compartment with a flexible hose leading downwards from that outlet to beneath the vehicle. This should permit gasses venting from the cassette to exit from the toilet-locker (though I’ve added a SOG system that extracts such gasses via a fan) but it does not surprise me in the least to learn that your motorhome (it might be helpful to know its make/model/year) lacks a similar arrangement, as adding a ‘vent hose’ might well prove tricky.

 

The fact is that (as Robbo has mentioned) prior to Thetford introducing toilets with cassettes that vented through their underside, all earlier Thetford cassettes vented via a valve in their upper surface that opened automatically when the cassete was inserted into the cassette-locker. In those instances the cassette vented gasses directly into the locker and the locker itself was not normally vented to the outside air. This arrangement seemingly was not problematical UNLESS the cassette-locker had not been hermetically sealed from the motorhome’s living area. Failure to seal the locker from the living-area meant that stinky gasses found their way inside the vehicle, as I very soon discovered with my 2005 Hobby motorhome.

 

As long as your Thetford C402’s cassette-locker is properly sealed from your motorhome’s living area, I shouldn’t worry about the locker not having a vent to the outside air. And if it’s not sealed, you’ll soon find out. ;-)

C400-4.jpg.85cb7b3c497087e489c255f9e427e6ff.jpg

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DavieR - 2017-05-17 7:59 PM

 

Thanks Robbo.

 

Maybe I 'm getting confused by the SOG system for the C400. It vents the cassette from the cassette bottom and, via the filter, out through the floor.

 

We will see how we get on this weekend.

 

Just for the record, there are two sorts of SOG kit that can be used with a Thetford C400-type toilet. One kit (normally) has the extractor-fan unit mounted on the cassette-locker door, whereas the extractor-fan unit of the alternative ("SOG II") kit will usually exhaust through the motorhome’s floor. In both cases smelly-air extraction will be from the vent in the cassette’s underside.

 

If you are interested in the SOG system for a C400 toilet, it was discussed in this earlier thread

 

http://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Thetford-C403L-toilet-Installing-SOG-system-/41205/

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Many thanks Derek, much appreciated

 

The locker looks well sealed off to me, but I'll know by Monday!

 

Shire, our converters, have recommended the door venting SOG kit, possibly because of the difficulty/impossibility of fitting the Type II kit. Without wanting to drift too far from my original question, can anyone tell me the depth of the filter cover? There is very little clearance between the sliding door and the toilet locker door.

 

PS our fan is a Ducato 2.3 130bhp converted by Shire.

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Measured from the face of the body-panel insert in the cassetter-locker door, the current type of filter housing (photo attached) protrudes 27mm.

 

As you should have gathered from the forum link I provided in my last posting above, the SOG Type D kit for a Thetford C400 toilet can be a real swine to fit.

 

There’s a video-clip here

 

https://www.youtube.com/watch?v=YOPG3tMKCQs

 

and somewhat out-of-date instructions here

 

https://www.caravansplus.com.au/pdf/sog-type-d-C400-fitting.pdf

 

Fitting the fan-unit/filter to the locker-door is straightforward (though particular care needs to be taken regarding their positioning) but needing to work at arm’s length inside the locker itself really complicates the rest of the installation process.

1461591909_SOGfilter.jpg.301a1b52fdb40c32962b10df8711fff6.jpg

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Thanks again Derek, I'll check if we have enough clearance for the filter housing.

 

Just back from our first trip. After 17 years in a VW T4 we feel like newbies in our Ducato, but it's all very exciting.

 

 

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