Thetford Toilet Problem

I've had a few Thetford Cassette toilets and I've never had a vent in any of them.

Is the rubber gasket damaged or out of place, the system should seal off when the slide is closed.

Haven't seen a vent of any sort on ours either - the waste tank seems to be a 'sealed' container once the slide hatch is closed - you must have a dodgy seal (they are a consumable item it seems) - one other possible cause is gas production in the waste tank, but correct use of recommended chemistry should prevent that.

HI
Are you using any chemical to contol odours such as Sodium hyper per carbonate [Napisan]?
That should remove the odours generated
There may be a small vent just to the upper left of the bowl opening
This is operated by the bowl slide oping KNOB
It's purpose is releases gas preesure fro mindie the lower tank just before the BOWL slide opens
It may not be sealing when the BOWL slide is closed,v letting gasses continiously escape into the van


PeterQ

Never had a smell in the van. Important to use chemicals, some better than others.
2/3's full = how many days? Do you have a policy of "no poo loo" they tend to smell more. A few solids give the chemicals something to work on. ^_^ No matter what they need to be emptied after 3-4 days.

To ensure the tank is sealed, when you empty it spay olive oil around the flap and seal. Use use only olive oil and it's available in spray cans at most supermarkets.

External vent fans were being promoted as after market items a few years ago, none of the reports I read convinced me to buy one.

If you wish to go down the "napisan" path, use the Aldi stuff in the purple container, it appears to have a higher active oxygen content. Otherwise stick to to the Thetford blue or green chemicals. We have tried a few of the home brews and so called environmentally friendly concoctions and have become very wary of their claims. It pays to read the contents very carefully to see what you are paying for. One tablet brand is nothing more than "napisan" compressed into tablet for which you pay a fortune.

Cheers