# fresh water and toilet full indicators



## commuter (Jul 13, 2011)

having just spent our first full week in our MH I have a couple of queries.

Our fresh water tank indicator gauge shows 1/4 full when it's 1/2 full and 3/4 when it's up to (what the previous owner marked on the side of the tank as the) max

The toilet full indicator light does not come on (rather unpleasant when we found out)

Any ideas?

Are there sensors in the water tank which need cleaning? What do they look like?

Is the fuse next to the Thetford cassette for the flush, the indicator or both? 

As usual any help appreciated


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## midlifecrisismil (Sep 27, 2009)

Hi there

Sorry cant help with the Thetford only to say that if you use it regularly (we normally use campsite facilities and the Thetford only at night and on occasions when we are on the road) I would empty it at least every two days.

With the water the guages on MH are notoriously inaccurate. In ours for instance if we have filled it to say 50% and then used the water the fresh water can say 20% and the grey water 10% so it seems that we lose water somewhere:? :? :? :? (although I know the Thetford uses it).

I would recommend to fill to where the previous owner suggested and if the grey and the fresh are the same sized tanks then when you get down to 1/4 on the fresh empty the grey.

Milly


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## Ozzyjohn (Sep 3, 2007)

Hi,

I agree that the gauges are not to be relied upon - best to think of them as a guide rather than anything absolute. 

I sometimes fill our fresh water tank on our (slightly sloping) drive before we set off. I fill it to overflowing - but the gauge only reads 75% full - yet when I park up reasonably level on arrival at a site etc the gauge reads full. 

The difference between it reading 100% and 75% can only be a very small amount - it isn't a sliding scale (at least on ours it isn't).

As for the toilet, I'm not sure about the fuse and the light. On ours it certainly supports the flush. I'd stick to using a mark 1 eyeball to judge when it is getting full - it's an easier task when it is less than brim full, that's for sure. 


Regards,
John


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## commuter (Jul 13, 2011)

thanks for the replies so far. I've started emptying every 2 days as there are 4 of us it probably needs to be every day and I guess it's better to do it too often than have a problem en route when we have 2 toddlers with weak bladders


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## tulsehillboys (Jul 22, 2010)

If you have the rod type sensor in the water tank - clean them with some fine wire wool or pan scrubber - might help...

Does the light come on if you take the cassette out of the loo?
If not the light or the sensor behind the cassette could be out.

The whole valve assembly comes off the cassette by a slight turn and gives good access to the interior (if you are brave!)

:lol:


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## Lesleykh (Apr 13, 2009)

If you have the storage space (we don't), some people have bought a second Thetford cassette, which seemed to me to be a good idea. The only drawback would be carrying/storing the full one while driving around - maybe they have lots of bin bags too!  

Lesley


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## Ozzyjohn (Sep 3, 2007)

Lesleykh said:


> If you have the storage space (we don't), some people have bought a second Thetford cassette, which seemed to me to be a good idea. The only drawback would be carrying/storing the full one while driving around - maybe they have lots of bin bags too!
> 
> Lesley


We are thinking of doing this (we do have the space) - I've noticed that it seems to be cheaper to buy a second cassette as part of a service pack rather than as a single item. The service pack includes a new seat and some toilet chemicals as well and seems to retail for less than the price of just a cassette.

Regards,
John


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## commuter (Jul 13, 2011)

tulsehillboys - thanks for the info I'll check what happens when I remove the cassette later when I get home. I am brave enough if it means I don't have "waste" slopping all over me when I have to empty it

The worst part of emptying was that I had to carry it into my sister in laws flat to empty. Luckily she also owns the downstairs flat which is vacant at the moment so I could empty it in there otherwise it would be up two flights of stairs 

lesleykh - We don't have the space to carry another cassette and, as you say, I'm not sure about the hygiene side of that plan 8O


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## peejay (May 10, 2005)

> The toilet full indicator light does not come on (rather unpleasant when we found out)


On all the Thetford toilets we've had the 'full' light doesn't come on until its a few cms from the top, ie only a few more uses and it will be chokker.
We never rely on the light but just do a visual each time the flap is opened.

We carry a second cassette when wildcamping for long periods but as mentioned, you need to bear in mind the space it takes and also a full cassette is quite a bit of weight if your payload is tight.

Pete

edit, ignore the last bit, just seen your previous post.


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## commuter (Jul 13, 2011)

according to the manual the capacity of the cassette is 17 litres, there are 2 litres of fresh water in after each empty plus the "blue stuff" giving a capacity of 15 litres for use

when I was told by the kids that they "couldn't empty the toilet anymore" the bowl was holding waste which is never a pretty sight :-& 

So I reckon we had passed the few cm's from the top and still no light so I guess there is a fault


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## nicholsong (May 26, 2009)

If you want to check the operation of the 'full' light, next time you empty fill again to full with fresh water, re-insert cassette and check light is on. Don't forget to empty again!!

Geoff


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## Spacerunner (Mar 18, 2006)

FWIW

If your cassette does get overfilled it can still be cleanly emptied.

Open the cassette locker door and swing out the emptying spout.

Hold a suitable vessel underneath, ( no, not his favourite pint mug!!)
and gently and slowly unscrew the spout cap until the waste starts to flow.
Continue until no more waste runs out and replace the cap.
Remove cassette in usual manner and empty as normal.


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## commuter (Jul 13, 2011)

good advice Spacerunner. Thanks


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## commuter (Jul 13, 2011)

Thanks Nicholsong. Will try that later


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## erneboy (Feb 8, 2007)

Our water tank operates using four rods to sense the level. The 100% rod is in contact with the water till the level drops to 75%, the 75% is in contact till the level reached 50% etc. 

So we can be just below50% full but showing only 25% and so on. It's not a good system but I have become used to it and in our van I can see through the tank for a more accurate reading when I need it, perhaps you can do likewise, Alan.


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## Addie (Aug 5, 2008)

commuter said:


> The toilet full indicator light does not come on (rather unpleasant when we found out)


In my experience when the 'Toilet Full' indicator comes on it's already too late 8O

I'd not worry about it, prevention is certainly better than the cure for this one :roll: :lol:


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## Sideways86 (Feb 25, 2009)

you can test the casstte warning light with a magnet details are on the Thetford site.

it could be that the magnet inside the tank has come adrift particularly if the tank has been shaked hard during the fresh water rinse stage.

However as all have said all the gauges and lights need to be treated with caution and treated as a rough guide only in my experience gained with three different motorhomes, two new and one pre owned.

Hope this helps

Regards


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## sennen523 (May 6, 2006)

hI commuter,

Is your Thetford cassette the new type C250?

My cassette is the C250, and has a "float" switch in the tank. This is a very poor design, as tissue can jam the float. My alarm light does work but very seldom. I have just got into a routine of emptying the cassette every day.

As mentioned in other posts,many fresh water tank level probes are very inaccurate and of a very basic design.
My Auto-Trail (2010), fresh tank level indicator (probes) has never worked since I bought the van.
I am having new tank probes fitted at my Dealers next week.

Regards,
sennen523.


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## grizzlyj (Oct 14, 2008)

Hi

Our water level gauge has 5 level lights, stuck in at a height that the builder thought was a good idea. Just to see what these actually related to I spent an hour or so pouring 5l at a time into a big bucket to calibrate that with a marker pen on the side, then put water in a known quantity at a time into the tank noting when each light came on. 

So now I know it takes 270l when full, and each light means 40l.

Peace of mind.


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## commuter (Jul 13, 2011)

sennen523 - I don't think it is. I seem to think it's a c or cs 200

I emptied it last night and gave it a flush out, played with the connections and fuse but could not get it to show a light. Anyone know how would I could tell if it's a type with a magnetic switch or float valve for the indicator light?


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## Kev1 (Apr 4, 2011)

Ours Thetford doesn't have a light just the gauge.
It's not accurate and I have messed (wrong word maybe)with it lol.
I have ensured the inside of the cassette is clean and the float and magnet work ok. I just think the design is poor.

We have a spare cassette brilliant when wild camping.

The trick is to swap well before it's full. so storing till you get to a toilet block is no big deal.

Kev.


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## sennen523 (May 6, 2006)

Hi commuter. 

Mine is the Thetford with wheels. You can see the plastic float switch through the top opening.

Have you tried filling with water to check the alarm light? If it's a "float" switch type, make sure there is no tissue lying on top of the float. (make sure your 12V power is on).

Failing this, i would say there is a electrical fault somewhere.

Good Luck.
Al.
sennen523.


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## Spannerman007 (Jun 8, 2010)

*Toilet Full Indicator*

I had a similar problem on a C200.
I found that the external switch (that is activated by the magnetic float in the cassette) had been assembled the wrong way round.
It was a simple job to reverse it. 
The red light then came on before it got too full.

Spannerman007


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## Spannerman007 (Jun 8, 2010)

*Toilet Full Indicator*

I had a similar problem on a C200.
I found that the external switch (that is activated by the magnetic float in the cassette) had been assembled the wrong way round.
It was a simple job to reverse it. 
The red light then came on before it got too full.

Spannerman007


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