Thetford 250 wont flush

[mustard1972]

Hi all,

I have done a search on the site for the 250 but haven't managed to find the answer hence this new post..

My Thetford 250 fuse blew a couple of months ago, i replaced the fuse and it worked fine however on my pre check this morning before heading off tomorrow my toilet has failed again... the fuse is fine (swapped it with another one just in case), and i am thinking of buying a new switch panel on the top (i have sourced one in stock locally that i can collect tomorrow at 8am).

Question, what do i need to do to fault find?, i could pay out £20 for something that works ultimately works ok, is it the pump? (how do i test) , reed switch? or something else.

Any help appreciated, alternatively does anyone know a mobile magician (engineer) in the Cromer area who i could call when i arrive? (feel free to PM me)

Mustard

 

[otherclive]

Mine had a similar fault and I removed the switch panel on top and sprayed the PCB and contacts with electrical contact cleaner. Gently rubbed the contacts with some kitchen roll to wipe off any residue. Replaced it and it worked fine.

 

[chrisn7]

Working on our van, one thing I have noticed is that the PCBs in the various fittings do not have any lacquer applied to the solder side, unlike cars for example. This makes the boards prone to corrosion, so if you take otherclive's advice first get some lacquer spray from Maplins to protect it afterwards - only takes 20 mins to harden.
On the 250 toilet its not just the fuse that blows, but the terminals the fuse pushes into are complicated little things, that are virtually impossible to clean up so require replacement. Also the tracks on the little PCB by the fuse corrode to nothing stopping the level indicator working.
Sometimes the pump impellor sticks after inactivity - might need a manual twist to free it up

 

[mustard1972]

Thanks guys , will take a look

 

[mustard1972]

It was the top switch, thanks for all the advice guys