Thetford C200 series.

Problem:- flush valve working but does not fully close leaving a slight weep of water.
Conclusion:- the valve is working but need cleaning to remove a foreign body or de-scaling. It does not need replacement.

Remember that the toilet was delivered to the factory as an assembled unit with minimal installation work required. Removing it cannot therefore be rocket science. Remember also that the toilet is made out of what I rudely refer to as ‘plasticrap’ so treat it with care

Step 1.
Disconnect the supplies. Open the cassette door and remove the cassette. ON the left you will see a clear pipe delivering water, an electrical supply and, further back a corrugated black hose venting any odours or gases from the cassette. The water and electric couplings are behind a white plastic plate secured by two screws which also join the rear of the toilet to the front half and bowl. Take it off, put back the screws.
Disconnect the water hose by slacking off the jubilee clip and pulling the hose off the bayonet connector.
Disconnect the blue and brown wires from the connector block (I marked which was which on the block with a fine felt tip)
Disconnect the black hose by removing both ‘circlips’ and pulling the top end out of the housing.
Step 2.
There are four screws through the bottom of the cassette housing and the cassette slides into this housing along moulded plastic ‘runners’. There are gaps in these runners and the screws are there.
Step 4. Go inside and lift the whole toilet out. Tilt it forward first and then pull it up.
Step 5.
Go and have the beverage of your choice and a short break. Pat yourself on the back as it took me two days of fiddling around to get to this point.

I found that the toilet sat very nicely upside down with the seat on the floor and the back in the step well and was at a reasonable working height too.
Step 6.
With the toilet upside down in the place of your choice, remove the central assembly with the ‘floating’ block. Next remove the two brackets that support the outlet of the bowl to the cassette. Finally remove the three curved brackets that connect the bowl to the base and allow it to rotate. Two will come off without problems but the third needs to have access created to the second screw. This you do by removing the back screw on the attachment of the mechanism that opens and closes the blade valve and swinging the whole thing round enough to allow access to the screw. Congratulations! The bowl will now separate from the base but will still be connected by the flush hose and water supply.
Step 7.
Lay the whole thing on its side and the bowl will fall away from the base. Now you can actually see the wretched valve lurking between bowl and moulding. Maybe you can pull it out and disconnect it without further dismantlement but I also freed off the vacuum balancer to give me more scope. Its only two more screws
Step 8.
It is almost a racing certainty that you, like me, will see flakes of limescale on the rubber washer in the hose coupling, so clean what you can see and fill the valve body with Antikal, white vinegar or the acid medium of your choice while keeping the electrical bit dry. Seal the ends and leave overnight to pickle. The valve has a removable screen at the ‘in’ end and you should pull this out carefully with a pair of pliers. Take a needle to the tiny holes and poke out the accumulated scale and finish of by pickling that as well.
Step 9.
You need a hosepipe, 12v supply and an accomplice – in my case a retired Refrigeration engineer who gleefully informed me that this was an industry standard valve on a lot of refrigeration equipment but with a 12v supply instead of 230.. RE-assemble the valve and screen and connect to the hosepipe. Couple up the 12v supply with some sort of separation between the poles to avoid a short circuit and turn on the water. Watch as your accomplice connects and disconnects the 12 volts and the water stops and starts as the valve opens and shuts. There should be no drips or weeps when the valve is closed. If there are, repeat the pickling process.

Step 10.
Work your way back to Step 1, refitting everything in reverse order. If you have any parts or screws left over, worry.
When refitting the toilet into the space in the shower room moulding , it should wiggle back into place fairly easily. I had some problems with the forward end of the floor moulding catching under the edge of the toilet and of course it is the one place you cant see from inside or out but I put my hand up from underneath and moved the offending part and in the end the toilet practically fell into place after another day or so of frustration and struggles.

Having seen how the shower room moulding is made (plasticrap again!) I cannot say I am surprised that so many of you have had cracked trays. You almost have to ask if the thing is ‘fit for purpose’.
Next time you look at Thetford spares, just ask yourselves how much that little valve cost them to buy in, in their hundreds and all they had to do was shrink wrap it to be able to sell it…………..
Anyway you just saved a shedload of money so pat yourself on the back, bask in the glory and then relax with a suitable beverage!

If you have any problems with this just drop me a mail provoostv@zeelandnet.nl and I will see if two heads really are better than one. By the way, being the female half of the syndicate I gave myself permission to stand the completed toilet on the table while I cleaned and polished it. You, on the other hand may not be quite so lucky.