Thetford Cassette problem

Aug 27, 2020
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We have a problem with our Thetford C2 RH cassette. When flushing the pump continues to run and will not switch off. Have checked both the internal fuse and the external near the water holders and they are ok. The only way to stop the pump is to remove the toilet fuse. Have tried looking on the internet but cannot resolve. Can anyone help please.
 
Jun 16, 2020
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Perhaps the switch has stuck in in the on position. This is likely to be fitted onto a printed circuit board mounted just below a flexible Plastic push.

That would be my first thing to look at.

John

Edit. Just found this.
 
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Aug 27, 2020
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Many thanks for getting back so quickly. I am attaching a photo of the cassette as the plastic flush push on the LHS does not seem to be removable if this is where the pcb is located. I know on other models it is under the toilet lid which ours doesn't have. Any further help would be greatly appreciated.
Regards and thanks
 

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May 2, 2020
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The c2 doesn't have a PCB the flush is operated by a microswitch, the centre part of flush button can be removed and a screw at the bottom, I found this on youtube that may help (sorry the video is a bit long and covers other problems) but the best I could find
View: https://youtu.be/c7C3sMHu0Qs
 
Jul 27, 2020
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I fully rewired mine the other day, exact same toilet. Finding out how to get the switch unit off from inside the door (on outside) was not fun, until I sussed it! 4 screws dropped the unit out. I used a meter to check for continuity when switches were pressed. There are two reed switches, one is a safety so the flush won't work when the loo cassette is removed. The other is the push switch to allow power to the pump. I have to say, if I was to start again, I would seriously look into whether I could convert my toilet to the manual pump. Those things work lovely and no silly electrics to go wrong. How hard is a brief turn of a handle versus a brief push of a troublesome switch?!

Anyway..... I found the 'safety' switch on mine was faulty so I just removed it, soldered the wires together so now if the cartridge is out, the flush will work. Will serve someone right if they forget :D. I replaced all the wires as they had bad oxidation/corrosion on them. It took me a very long time to figure out that even though I was seeing 12volts, the pump (new) wouldn't run, and then I realised the corrosion was limiting CURRENT, even though the voltage appeared to be there. That's my conclusion anyway, and replacing the wire with decent wire (tinned copper conductors, although you needn't do that, I just had some spare) solved it. Now working very nicely.

Reaching in to get at those 4 screws was probably the hardest part of the lot. If you can get that unit off, worst case you can just buy a replacement. Or you could replace just the reed switch if that's at fault. Not sure if this helps, but I feel for you either way :D
 

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