Toilet flush fix...thetford 402 c series, 2004 sonata

[AndyD]

QUite a boring longwinded post but might be useful to someone

My toilet flush hasn't been working sonce buying my van a month ago, pretty much been clueless about how to fix it so done some digging around in the toilet unit and also on the internet.

I first changed the 3A fuse in the cassette compartment..no success.

started tracing the wiring to see where the feed came from, I found a purple and white wire comiing from the back of the heater, this was identified as the feed for the toilet, tested these and they were fine.

This feed had a small junction block where the wires passed from the wardrobe into the toilet cubicle, tested at the nearside and farside of the block, again no faults.

opened the cassette compartment, removed the cassette and checked the 3A fuse which was fine.

checked the readings from within the fuse holder and they were fine.

Next I had to remove the flush handle which is removed by simply pulling it off., the cover which houses the flush switch and related wiring also just lifts striaght off but needed prized up a bit with a thin screwdriver.

I then removed the large connector from the circuit board, this was the feed which controlls the power supply to the pump, tested the power in which was fine and then checked the power to the pump which had to be done by attaching the meter to the visible contacts on the circuit board which are beside the live feed.
pressing the button renealed that power was being sent to the pump.

I thereafter removed the small kidney shaped tray which has a gromit for the pump power supply to go through, this just pulled off,

The access hole this leaves is small and this made getting the pump out quite fidgety but it did eventually come out of the hole with both the power supply and the water hose still attached.

I then manually turned the pump and tried to flush again but still no joy.

As a last resort I resorted to neanderthall methods and hit the pump with two small taps of a hammer. Hey presto!!!!

A working toilet pump

I wish I'd just hit it with a hammer in the first place...lol. I've learned a lot about the toilet system doing this and I'm sure it'll be good knowledge to have for future failures while on the road.

[AlanandMel]

Well done !

Excellent investigation Sherlock!

[AllanandJackie]

Good job, a fairly common issue.

I've been told by another member to add a very small amount of washing up liquid to the top tank water to lubricate the pump shaft to prevent it from sticking. Do this every couple of top tank fills.

[AndyD]

That sounds like a good idea, I have still to lubricate the cassette seal with olive oil and completely empty the water holding tank and replace the water properly with the pink fluid.

The tank has been filled with water and blue chemical which may have added to the gunk in the system which appears to have been the cause of my problems.

[AlanandMel]

Could be Elsan Organic. That is blue and you use it in both top and bottom tanks.