Everytime I start up my Dellpoint Eoropa 75 pellet stove it soon starts to go into shut down mode and reads F6 . I have cleaned out the ash auger and have changed the fuse 3 times and it keeps doing the same thing. i have also checked the ash auger motor with a 9v duracell and it seems to work . What else could the problem be. Is there anyone that can help.