does machine have lack of suction ?
(oh yes just read your first post again.)
If so, press red release button, pull shaft up and see if suction is there on the pipe end.
as you pull the pipe out of the hose you should hear changeover valve assembly go with a little thump.
If suction is there at the hose then there is a blockage from the changeover valve to the head assembly.
Try that, i can do a vid possibly on it, the 24 is prone to blocking i find from the head exit to side pipe to flexi link.