Need to rule out that the sump drain filter is not the cause of your problem.[The large black hose that leaves the outer drum].so lower the drain hose into a bowl place on the floor water should flow out, if a trickle suspect blockage in the pipe/pump, if a fair rate flows suspect drain pump
1) STRIP the filter out, and CLEAN.
2) STRIP and check operation of drain pump .
a replacement pump maybe required .
wirecutterman, January 2009