Thetford flush antifreeze??

[Guest John Windwood]

Hi All This is my first winter with our VW Karmann Gipsy. We intend to use it year round, so I am very interested in winterising techniques. I think I have it all understood except for the Thetford C2 cassette toilet. I naturally want to keep the flush tank full, but am aware that it may freeze. I have heard of antifreeze that can be used, but am having no luck at all finding any. Does anyone know of the availability of any suitable products? Many thanks in advance.

[Guest PeteC]

Hi John Dont know where you will get the antifreeze and dont think the vehicle stuff will do We have met people with "winterised continental vans" with frozen tanks & pipes so I dont really trust the winterised claims (they onlt claim down to -15C & we have had -23C last winter here on the west coast at sa level) We carry water in 4 x 8litre cans (we paid 2€ for them full of drinking water in Spain) when washing up we use a bowl in the sink & pour this into the cassett If you empty this morn & night there wont be sufficient to couase problems if it does freeze (never had that happen)but the heat inside the van is usually enough to keep it thawed

[Guest Clive]

Not an expert at antifreeze but I would guess that the stuff one puts in the radiator which contains methonol may melt the plastic and knock you out with the fumes! (1) BUT SALT will stop it freezing if you put enough in but it will probably knacker the pump and seals. (2) How about hanging up a water bottle in the corner of the loo with a flexible plastic pipe with a "press on" type of tap on the end. As this will be inside with you it should not freeqe. (3) If you intend using sites with a hookup then electrically heating the loo cupboard could be a good idea. Hot flushes no less! (4) Is it possible to fit some ducting to route some of the warm air from inside the van through the loo cupboard? Hope some of these ideas give foor for thought. I would look at (4) first as it will warm both tanks and could be the simplest. Good luck

[Guest Mel E]

Use Milton - the sterilising solution. A dilute solution lowers the freezing point of water. See the packet or contact the manufacturers for full details.

[Guest Neal]

John If your flush holding tank is seperate from your fresh water tank then you can use potable antifreeze. You can use this in the fresh water system but only for lay-ups, not to use and consume. This is widely available from any US RV accessory dealership. Let me know where you live and I'll advise you of your nearest (ish) outlet. Regards Neal (nealbarb1@supanet.com)

[Guest Derek Uzzell]

Thetford used to advise that an anti-freeze could be added to their toilets' flush tanks. (I can't recall which anti-freeze, but I think it was a non-methanol based automotive type.) Nowadays, "for environmental reasons" they advise against this practice, just saying that there should be no problems if the toilet is situated in a heated location, otherwise it should be drained down. The C2 bench toilet has a 16 litres flush tank and, if you keep this topped up, that's a lot of water to freeze. Having said that, there are elements of the C2 that are more vulnerable to frost, such as the glass 'sight tube' that shows the water level in the flush tank. You might think about lagging these in some way - simply packing a blanket inside the cassette-locker door should help considerably. Personally, I'd adopt PeteC's pre-emptive strategy - drain the flush tank and keep some water for flushing the loo in a plastic container in the toilet compartment. If you must use anti-freeze, I'd follow Neal's advice. (Though what the stuff will do when it hits the waste in the cassette is anybody's guess!) I'm a mite startled by Mel E's suggestion. Milton's main active ingredient (16.5%) is sodium chloride, so it's not surprising it will lower the freezing point of water. However, for the same reason, Milton is corrosive to metal - even stainless steel - which is why the manufacturer says "avoid prolonged contact with metallic objects". I would have thought that a worthwhile reduction in the flush water's freezing point would require a fair concentration of Milton and risk corroding the toilet's metal components. (I gave up using Milton some years back having seen the effect of a very dilute solution on the metal parts of my Truma heater as the result of a long-term minor water leak.)

[Guest John Windwood]

Thanks to you all for your advice. Neal-I have sent you an email-would like to know where I can get that antifreeze. Also a good idea to stuff a some insulation in the cassette door space-wouldnt have thought of that! Thanks again. John

[Guest Derek Uzzell]

For what it's worth, I've now found Thetford's earlier "COLD WEATHER USE" instructions. These were copied into a 1997-vintage Compass Owners Handbook and relate to C2 (bench) or C200 (swivel bowl) toilets. The C2 advice says "Use a non-toxic (propylene glycol) type of antifreeze. Refer to chart on container to obtain level of protection". The C200 section also recommends propylene glycol but adds the words "or an antifreeze such as those used in car radiators". However, RV-type antifreeze sounds like the best bet nowadays.

[Guest Don B]

John, I think that the anti-freeze used in solar panels for hot water generation is not-toxic, so this might be of some use to you. It is available from plumbing suppliers such as Plumb Centers all over the country.