Question

my Thetford C250 cassette has flushed three times on its own,(without pressing the blue flush button) so overflowing the toilet and flooding the bathroom. What is causing this and how do I get it rectified.

Answer

This is a problem with the electric valve and you will need to replace it, our part 129433. Details how to do this can be found on site - go to Thetford C-250 Cassette Toilet.