First time wintering in our 3050. Have been letting black tank fill to just over 2/3, then flushing, using pucks each time. No paper. Last week heavy smell noticed, used tank wand flusher on hose seemed to work, now smell returned again, seems sensor may be clogged as after dumping sensor still reads 1/3 or 2/3. Went to try external tank flush, hose bib inlet located passenger side above rear wheel bunk. Hooked up hose, opened flush valve as instructed, and no water appeared to enter tank at all. Called home repair shop he advised me to look for plate near inlet valve at black tank? Looked everywhere cannot see possible access. My quess is somehow prior use( coach was ex-rental?) maybe full clean out did not occur and something had now hardened and blocked black tank inlet?
Any suggestions on how to open/ allow this flush valve to work?
First photo shows inlet,second is large plastic try that is attached to coach underneath the inlet location.
Thanks!😃