Thetford toilet PCB problem

Tried to reply yesterday but failed.  An awkward one to solve. Are you talking about the circuitry on top of the tank to which the press button is attached?  If so my saga may help.   A few years ago my wife pressed to button to flush and it would not stop flushing!  Power off then I prised the cover off to expose the circuit board and sprayed it with WD 40 eletrical stuff, no problems since.  Don't know how water can get there other than by condensation, using the shower - if in same compartment, or a tiny crack/hole in the tank.  Captain (what's his name) crack sealant may help if you can see any possible problem there. Thetford wcs and us have a chequered history.  The ratchet operating the slide on the cistern slipped, access is from underneath,  and to make it worst as I was  trying to remove the cistern it got stuck; judicious use of a knitting needle allowed me to ease the connector on the swivel.  The pico switch operating the red 'full' light ceased to work, luckily it was a simple and cheap hew switch.  Think I would draw the line at replacing the float/magnet inside the cistern.  Don't think it is possible to convert to a manual pump.

Yes, that's what's causing the problem. Mine firstly carried on flushing but then started to flush without the button being pressed. The PCB was sprayed with WD40 but has still failed. I've spoken to the 'customer care' department at Thetford but they could not suggest any cause or remedy. 

I've got an engineer coming to look at it soon, so I'll post again if he comes up with any suggestions. 

Obtain from Farnell's or similar co. some conformal coating and spray your new PCB with a complete covering except for any connections (tape them up) ensure an even complete coat (even 2 or 3).

This should avoid any further propblems from condensation or accidental moisture contact.

Conformal Coating is like a clear varnish but is special for PCB's.to protect them from moisture.

Good luck ron.  Sure you will be able to solve the problem.  The PCB should be dry.  Like Richard's suggestion.

Thanks Richard - that's certainly something I will try and I've found the product on the Farnell website. I'm hoping the engineer will be able to identify the source of the water ingress. 

Hi Ronhub.... did you ever solve the water ingress issue with the Thetford toilet?