Thetford C250 won't flush

Aug 7, 2013
267
157
South Wales
Funster No
27,380
MH
swift kontiki
Exp
I'm a newbie bought our first motorhome 7months ago and love it
Last week our thetford C250 toilet stopped flushing
I've put a multimeter on it and have 12v at the switch. Trying to decifer if it's the switch or there's another small circuit board that tells you when the cassette is full.
Does this disable the flush when tank is full?
So I can try an isolate the problem.
Is it the switch or tank censor

Cheers
 

Jaws

LIFE MEMBER
Sep 26, 2008
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No mate.. the cassette full LED is nowt more than that... it is switched by a float arm with a magnet on it inside the cassette..
It can really only be the switch or the solenoid ..
 

icantremember

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Sep 2, 2010
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It is probably the circuit board behind the press switch has been pushed out of its mounting clips ..... simple to fix by pulling off the switch facia and pressing the board back into the clips.
Good luck and hope you will soon be flushed with success.
 
OP
TheDentons
Aug 7, 2013
267
157
South Wales
Funster No
27,380
MH
swift kontiki
Exp
I'm a newbie bought our first motorhome 7months ago and love it
Ordered new push switch and reed switch fitted both still nothing the reed switch looks different and the full light is permanently on have 12v to the button but doesn't flush when pressed
 

dabhand

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Feb 19, 2014
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Ordered new push switch and reed switch fitted both still nothing the reed switch looks different and the full light is permanently on have 12v to the button but doesn't flush when pressed
Each time you scratch your ear, pray that it's wax:)
 
Nov 6, 2013
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S. Ayrshire
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The usual
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Since the beginning
Check voltage to the pump when flush button is pressed.
Or
Apply a known good 12v source straight to the flush pump terminals.
 
Dec 12, 2010
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Maybe your pump has siezed or stuck ? Can you get at it to give it a gentle tap or at it's terminals to try connecting it direct to 12 volts ?
 
OP
TheDentons
Aug 7, 2013
267
157
South Wales
Funster No
27,380
MH
swift kontiki
Exp
I'm a newbie bought our first motorhome 7months ago and love it
Taken pump out runs fine independently I'm baffled
 
Nov 6, 2013
1,154
2,002
S. Ayrshire
Funster No
28,914
MH
The usual
Exp
Since the beginning
If it's the same housing / type that was used on our old Thetford 402(?), it wasn't easy to see.
A 3A small blade fuse if memory serves me correct
 
OP
TheDentons
Aug 7, 2013
267
157
South Wales
Funster No
27,380
MH
swift kontiki
Exp
I'm a newbie bought our first motorhome 7months ago and love it
Fuse is fine I have power to the switch, the only thing that I can think of is that it's the wrong reed switch stopping the toilet flush
An earlier post says the reed switch doesn't effect the flush
Does anybody know this for certain
Cheers
 

Jaws

LIFE MEMBER
Sep 26, 2008
21,212
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Narrfoook
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C class, Autotrail Chief
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since 2006 ( I think ! )
Not according to the installation information it doesn't, but it is possible to modify anything I suppose.. Not sure a reed switch ( unless a big one ! ) would have enough contact area to handle the switching current of a pump or solenoid.

It does depend if the reed switch is N O or N C ( Normally Open or Normally Closed ) but...

Simple checks
If it needs to be open then just disconnect one of the feed wires to it and try the flush ( This seems very unlikely though )
Just use a clip lead across the reed shorting it out and see if the flush works.
 
Dec 12, 2010
2,964
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Cumbria
Funster No
14,651
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C Class
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since 2011
How old is the toilet ? The reason I ask is in our old Adria caravan a few years back, the toilet stopped flushing and after a lot of searching, I found that the copper wires in the supply cable to the toilet had gone black, a common problem on DC supplied appliances. Anyhoo, I could get 12 volts on my digital multimeter at the bog but not enough current down the wire to run the toilet. Had to run a new supply cable to sort it out :(
 
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