Hello - Can anyone tell me if they have ever repaired the handle to backwash on a Pentair DE filter. It is just plain stuck and won't move. I called Pentair and support told me to open up the whole thing and get to the bottom - maybe you need a new rotor part. Well I checked the schematic and don't see a rotor part. I'm afraid to take the whole thing apart and not be able to get it back together again. Any advice is appreciated.