I wouldn't put in a higher limit switch to try and solve your issue! you may burn down the house. there may be an issue with your board feeding to many pellets and over firing the stove now, so raising the limit could just damage the stove itself
The circulation fan(convection fan?) does comes on, but does not stay on if I press the fan button like I think it is supposed to. Because the high limit switch is triggered on level 3 or higher, I wanted to keep the fan on high. Sooooooo....I pressed the fan button and nothing different happens.
make a test cord and plug the convection fan in so it runs continuously. Then turn stove on and start as normal. leave the fan setting button alone just make sure its in auto. And see if stove works. If it trips again you probably need a new convection motor and possibly a new board