The first one lasted three years and went bad about 2 months ago. The replacement lasted one or two weeks and then it went out again today... This started to seem like more than a coincidence, and after some thinking it hit me that I have rebuild my external pellet silo this autumn, and as a result of that I turned the pellet chute to the left instead of to the right as it was before. This caused the poor sensor to be bombarded by the falling pellets as most of it now fell on the right side of the burner where the sensor is, so it likely failed because of mechanical stress. I cut a bit of sheet metal and fastened it with a rivet to make a protective roof for the sensor, hopefully that was really the cause and it will last a little bit longer now. And now I need to order another spare, for the third time. Anybody else have the same experience?