Leaking toilet flush ,Thetford

[vindiboy]

My vans Thetford toilet flush has started to leak water when flushing, the water drips into the cassette holding area and if left it becomes quite deep, it only leaks when flush is used , I have left the pump switched on all night with the cassette removed and all is dry [ my flush water comes from the main tank ] the model of my Thetford is C 200 S WH it is 16 years old , I suspect there has been some frost damage to the system whilst the van was not being used although every thing was drained down [ I thought ]

I guess I am going to have to remove the complete toilet assembly from the van to get at the works of the thing as working from inside the cassette compartment would be near impossible I think, the toilet bowl swivels for ease of use and I can see the hoses feeding the flush in part but as I say getting at things will not be easy unless I disassemble the toilet completely , and I cannot see the point of the leak from the underside of the bowl looking in from the cassette door.

Removing the complete toilet appears to be simple enough as I can see the fixing screws and the main hose connection, but I am wondering if any of you have had a similar problem and know any short cuts ?

I can still use the van as long as we do not flush the toilet bowl , I can use a bottle of water to do this and a spray bottle of detergent or similar to squirt into the bowl , thus keeping the van on the road until a full repair is done ,

So any ideas would be very welcome .

I have found an exploded diagram view of the toilet on line , but it has a manual flush but is not too dissimilar from what I can see of mine , mine has a remote flush switch on the side of a toilet cabinet. HELP !!!!! Leisure Shop Direct on line seems the place for spares etc, it was on their site I found lots of explode diagrams for the Thetford and other motorhome components so might be a good place to go to for any other Motorhome problems you may have and they have a large range of spares available , including my flush tube for £15 if that is the part I need ?

[Derek Uzzell]

Your Thetford toilet is a C200S model (example here)

 

https://picclick.co.uk/Thetford-C200S-Recessed-Cassette-Toilet-Electric-Flush-173946352776.html

 

My 2005 Hobby motorhome had a C200S toilet, but I never had occasion to do any work on it (other than to fit a SOG unit). Certainly some repair tasks would normally be performed by working within the cassette locker, but if you can remove the complete toilet fairly easily, repairs are likely to be more straightforward.

 

The 'guts' of a C200S will be much the same as those of a C200CS that has an integrated control-panel on a separate plastic moulding behind the toilet bowl-unit, rather than having a 'remote' control-panel and no moulding. Drawing and parts list here

 

https://dffppahacqx22.cloudfront.net/api/v1/Document/935/ContentDownload?h=Spare_part_list_C200.pdf

 

 

 

[747]

As I replied to someone else on a different forum with the same problem, it seems to be common on Thetfords with an electric flush. I had the problem a few years ago.

 

When you drain down there is water left above the solenoid in the toilet. you need to drain everything down and then operate the flush. When the solenoid is operated and the pipework is empty, the water should run back. Your pump will run dry but it is only for a few seconds. On some vans you may be able to turn off the pump and the solenoid might still work.

 

Having low heating in the van over Winter is not necessarily a foolproof way to prevent toilet damage. I had low heating but it never worked its way through as far as the plastic pipework inside the Thetford.

[vindiboy]

Thankyou

[Derek Uzzell]

My understanding (from this earlier forum thread)

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Using-compressor-to-blow-out-water-lines/57098/

 

is that 747’s Thetford toilet is a C3 bench-type model, whereas Vindiboy’s toilet is a C200S swivel-bowl model. Although both models are supplied with flush-water from the leisure-vehicle’s main fresh-water tank, there are significant design differences.

 

An Installation Manual for C200 S/CS models can be downloaded from here

 

https://www.thetford-europe.com/gb/products/toilets/cassette-toilets/c200-cs-no-longer-available

 

(which may help regarding removal.)

 

Thetford used to make available online a comprehensive ‘how-to-repair’ document, but nowadays Thetford’s approach is to use YouTube videos for the procedures involved. This playlist relates to C200 models

 

 

and this video shows how the toilet-bowl is removed from a C200 S/CS model in order to access the electric valve

 

 

In this recent forum discussion

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Thetford-toilet-problem/58291/

 

Robbo said

 

...your problem is probably due to grit getting lodged in the electronically controlled water supply valve, allowing water through to fill the toilet.

 

First try operating the toilet flush button numerous times. If that doesn't shift the debris, you'll need to detach the pipe from the water fill container and apply compressed air via a footpump or similar.

 

I had the same problem and compressed air resolved the problem.

 

So that advice would be worth trying first.

 

[vindiboy]

Derek Uzzell - 2021-06-23 7:25 AM

 

My understanding (from this earlier forum thread)

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Using-compressor-to-blow-out-water-lines/57098/

 

is that 747’s Thetford toilet is a C3 bench-type model, whereas Vindiboy’s toilet is a C200S swivel-bowl model. Although both models are supplied with flush-water from the leisure-vehicle’s main fresh-water tank, there are significant design differences.

 

An Installation Manual for C200 S/CS models can be downloaded from here

 

https://www.thetford-europe.com/gb/products/toilets/cassette-toilets/c200-cs-no-longer-available

 

(which may help regarding removal.)

 

Thetford used to make available online a comprehensive ‘how-to-repair’ document, but nowadays Thetford’s approach is to use YouTube videos for the procedures involved. This playlist relates to C200 models

 

 

and this video shows how the toilet-bowl is removed from a C200 S/CS model in order to access the electric valve

 

 

In this recent forum discussion

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Thetford-toilet-problem/58291/

 

Robbo said

 

...your problem is probably due to grit getting lodged in the electronically controlled water supply valve, allowing water through to fill the toilet.

 

First try operating the toilet flush button numerous times. If that doesn't shift the debris, you'll need to detach the pipe from the water fill container and apply compressed air via a footpump or similar.

 

I had the same problem and compressed air resolved the problem.

 

So that advice would be worth trying first.

Thank you very much Derek, the video from U Tube is great, it is as I expected it to be , all looks very simple but a lot of hassle as are all jobs we really do not want to do , but hey ho one gotta do what one has gotta do, I am pretty much convinced that it is frost damage to the valve shown, it is not grit in the system as no water escapes when the flush is not used , only escape is leaking water from a break somewhere in the pipe work or valve, I won't know for sure until I dismantle the toilet, The repair will take longer as I cannot order parts until I know what exactly is needed so a wait for delivery is inevitable, thank you all for your advice.

[vindiboy]

well I removed the complete toilet assembly today from my van, quite straight forward really, I then dismantled it completely to find what was wrong, couldn't find any frost damage but the hose connections were not good, no clips on any joints just pushed on, , I have ordered a complete new inners for the toilet from E Bay cost just over £70 delivery Monday next , belt and braces I know but at least I can be sure I have fixed the leak I hope.

[colin]

We had a problem with the 'anti syphon' (or what ever it's called) leaking water when flushing, took the toilet apart and checked everything out and couldn't find a definitive problem, it later turned out to be the water pump starting to fail and struggling to produce enough pressure to close the valve.

[Derek Uzzell]

I’m guessing you are referring to the ‘vacuum breaker’ (example here)

 

https://www.awnings.co.uk/thetford-vacuum-breaker.html

 

that is fitted to Thetford cassette toilets that have an integratef flush-water tank.

 

My understanding is that Thetford toilets that have their flush-water supplied from the leisure-vehicle’s main fresh-water tank (like vindiboy’s Thetford C200S model) do not have a vacuum breaker.

[lancepar]

I've noticed our toilet has started to get small puddles of clean water on the top of the cassette when it's removed to empty.

 

Not been able to find where the source is but it sounds like the early stages of vindiboys problem.

 

Watching thread with interest.

 

B-)

[vindiboy]

lancepar - 2021-06-25 10:39 AM

 

I've noticed our toilet has started to get small puddles of clean water on the top of the cassette when it's removed to empty.

 

Not been able to find where the source is but it sounds like the early stages of vindiboys problem.

 

Watching thread with interest.

 

B-)

Yes that is how my problem started, it slowly got worse so I am now fixing it as shown, good luck.

[vindiboy]

Derek Uzzell - 2021-06-25 8:19 AM

 

I’m guessing you are referring to the ‘vacuum breaker’ (example here)

 

https://www.awnings.co.uk/thetford-vacuum-breaker.html

 

that is fitted to Thetford cassette toilets that have an integratef flush-water tank.

 

My understanding is that Thetford toilets that have their flush-water supplied from the leisure-vehicle’s main fresh-water tank (like vindiboy’s Thetford C200S model) do not have a vacuum breaker.

Mine does and It appears to be working OK but I have ordered a new one and am going to fit it when I finish the complete refurb, better safe than sorry I think, my toilet is 16 years old so the spec may have changed since then ??

[vindiboy]

https://ibb.co/Gcpwg71 Toilet dismantle so far.

[Derek Uzzell]

vindiboy - 2021-06-25 10:45 AM

 

...Mine does and It appears to be working OK...

I live and learn ;-)

[lancepar]

Took mine to pieces and it looks at the moment that the vacuum breaker has gone in mine, going to test it. Either one ir both pipe stubs are fractured or the vacuum seal is no longer holding closed.

 

Just one thing, stuffed up the feed pipe from the blue pipe there is an orange insert with a small hole in it. If I wanted to find out what it does I would need to cut it out of the pipe but if someone knows it's function, I'll leave it.

 

B-)

[Derek Uzzell]

Explanation by "Brecon" in this 2012 CaravanTalk thread

 

https://www.caravantalk.co.uk/community/topic/74544-thetford-orange-thingy-ma-jig/

[lancepar]

Thanks Derek, I'll leave it be.

B-)

[lancepar]

Here's one Vacuum Breaker.........

 

https://tinyurl.com/yjdmjsj4

(I would emagine they are out of stock)

 

My local is getting one for £16.00 but a few on eBay cheaper, just one here.............

 

https://tinyurl.com/yhjch32m

 

B-)

[Derek Uzzell]

In this 2010 MHFacts thread

 

https://forums.motorhomefacts.com/88-generic-hints-tips/71255-thetford-electric-cassette-toilet.html

 

the following statement is made

 

On page 2 of our Thetford Manual it says:

 

"Note: Some vehicles are equipped with a high pressure water pump. This can result in a powerful flush that spills over the top of the bowl. In this case use the pressure reducer supplied (packed with the toilet instructions) This reducer must be inserted into the water hose at the point where the toilet is connected to the central water system”

 

A 2018 version of Thetford's installations instructions for C200 S/CS toilets says about the pump that provides flush-water:

 

Required pressure remote pump at the toilet inlet - Minimum 0.35bar at 4.2litres/minute, Maximum 0.70bar at 7.1litres/minute

 

and

 

Meet the required pressure for the remote pump at the toilet inlet to ensure correct flush. If the pressure is too high, install a flow reducer.

 

It seems likely that the latter instruction will apply to all Thetford cassette toilets that have their flush-water supplied from a leisure vehicle’s main fresh-water tank.

[Steve H]

I had a similar problem with my Thetford electric flushing toilet., though mine leaked whatever was in the bowl. I changed the rubber seal at the top of the cassette but no change. Then I mentioned it to my trusted habitation and repair people who told me that over time the cassette unit and it's floor can sag creating a gap between the bowl and the cassette. This usually leads to the replacement of the whole unit.

 

My solution was to use four twelve-inch plastic rulers. Glue to of them to the backs of the other two. Then glue (I used Gorilla) both 'double' rulers to the base of the cassette one on each side. This gave the additional height needed. Slid it in and no more problems, though I did choose to replace the cassette a few years later out of choice.

[lancepar]

Good fix Steve.

 

Mine and I suspect vindyboy's leak is from the pump, Vacuum Breaker or spray nozzle or the pipes or pipe connections to these items in the normally dry area underneath the bowl where they live. It's clean water.

I suspect in my case it's the VB because when bench testing it there is very little vacuum so water is no longer contained in the unit and is escaping from out of the hole in its top when the pump is operated.

 

When I get the new VB installed, I should be able to do a test before putting it all back together and go from there.

 

B-)

[lancepar]

Mine's fixed, it was the Vacuum Breaker.

New one comes with wire clips, there weren't any on the OE install. Thetford 16388 is the part number but like everything else at the moment bit hard to get hold of one.

 

My local has one on order but it aint arrived yet, so I found a place that had one and went and fetched it as the MH is away this weekend.

 

The Vacuum on mine had stopped working allowing water to flow out of the hole in the top of the unit.

 

Take plenty photos especially the order of the pipes on the VB. I found the job a bit long winded but possible with the bog insitu.

 

I have to confess that when I sterilize the water works I have never run the mixture through the electric toilet flush, I would imagine this is why the VB has failed. I will be doing so in future for sure.

 

B-)

[vindiboy]

My repair to the Thetford toilet flush is finished and all back in the van and working well, I replaced the complete flush from the water inlet to the out flush, cost me £75 in total including new water tubes , main valve ,vacuum gadget and flush pipe and fittings I could not find a definite leak source so as the toilet is 16 years old I thought hey ho replace all , so I did, I used jubilee clips on all the water tubes as I felt they were needed , although the only tube that is under pressure on my set up is the main water inlet from the main pump to its other end at the main magnetic valve, I removed the complete toilet from the van and worked on it on the bench, it would have been a nightmare trying to work on it in situ, only four screws and a fixed bracket held it in place so easy enough to remove the whole assembly.

[747]

vindiboy - 2021-07-02 9:50 AM

 

My repair to the Thetford toilet flush is finished and all back in the van and working well, I replaced the complete flush from the water inlet to the out flush, cost me £75 in total including new water tubes , main valve ,vacuum gadget and flush pipe and fittings I could not find a definite leak source so as the toilet is 16 years old I thought hey ho replace all , so I did, I used jubilee clips on all the water tubes as I felt they were needed , although the only tube that is under pressure on my set up is the main water inlet from the main pump to its other end at the main magnetic valve, I removed the complete toilet from the van and worked on it on the bench, it would have been a nightmare trying to work on it in situ, only four screws and a fixed bracket held it in place so easy enough to remove the whole assembly.

You are lucky. :D

 

To get my bench type out I have to dismantle part of the cupboards and some of the bathroom door frame. :-(

[Deffheads]

I too have had water sitting on top of cassette, so I purchased a new vacuum and spout and finally got round to fitting a couple of days ago. I did this in situ and after much swearing and bruising to hands, I would never do this job again. The access to fit the flush spout is ridiculous, the only way I could get it to fit, was to remove the pipe from the spout and fit that first, then warm up the pipe and struggle to fit to the spout. All done and seems ok at the moment. Never again, I think it would be easier to fit a complete new toilet!!