When you store or leave c/van for log periods its best to drain the toilet because like leaving water in the gardend spray you always end up with crap in the water. www.thetford-europe.com click service click Repairs instructions click staniaryware first one and down load the pdf which covers all models of toilet just search in it for yours save pdf to a folder. My guess is its lime build up on the pumps impeler shaft or the muck floating in th water has blocked the flush pipe. Try up ending pump turn impeller with small screwdriver or what you got to fit until it feels fairly free. the drop it in CLEAN water try it out.
Bob, October 2012
