Well, after much input, most of it good and intended to help, it looks like short of becoming somewhat of a plumber, there is a way to "solve" this problem. First....the paper.....solving the solvent you might say, Let the paper mellow in a bowl half full of water...you do this by slight pressure on the pedal...not enough to open a flush but just to fill in the water. Let it in there about 10 minutes....use the 1 ply if you can stand it or at the most 2 ply....either seems to break up easier. (ever notice that you use twice as much 1 ply as 2?...duh do the math) Good hint....flush often meaning if there are some logs in there, put them down before using the paper. THat will give them time to swim downstream. After using the paper and allowing it to break up...10 minutes seems to work......shut the lid (this might protect you from any splashes or burps) and flush fully......hold the pedal down for 15 seconds. If you don't see any water (or worse) backing into the bowl, you're good to go....in this case, that means leave, not the "go" you might think, Guys, have fewer problems....we only have to paper hang for one function while the ladies have both. Either way, let the paper mellow out and break up and then flush it fully. We had 3 good days of flushing following this procedure. We didn't use hot water or any of that, just letting the paper break up.
The cause is still debatable. Some say it's not a Thor problem but if they know there is a problem with this type of tank configuration, and still continue to manufacture it this way, it's their problem Say what you will....make excuses for Thor if you must.....as long as they don't improve on a bad design, it's still their fault. It should work without us doing all this "research and work." As I told some ACE renters before we left the campground...."it's more of an art than a science." That after they informed me their hot water was on the right, cold on the left and they had scolding hot water IN THE COMMODE! Seems wrong unless you really like HOTSH,,,,...another Thor construction problem. GOod luck to them and hoping as hot as the hot water gets in these things, they don't want to see a cracked bowl
Good luck, flush vigorously and often and let the water do to that paper what we know it can do. (you can see this if you put some water in a bucket or clear jar along with some of your TP..you will see the paper break up)
I love the ACE and I think THOR has some good techs that will help you on the phones but probably as with any other coach.....quality goes downhill when you're trying to keep up with the demand that seems to be out there.) Attaboys to Thor when they deserve them but held their toes to the fire when not..thanks to all who contributed on this several-year-old problem..