i have been burning my new-to-me 2006 Accentra insert for a couple of weeks now and it has been working great. But last night it started to make a faint but definitely audible noise intermittently when the auger feeds. It's kind of a whistling or squealing sound, almost like if the wind were howling outside in the distance. It doesn't happen all the time that the auger is feeding, just intermittently. Has anyone experienced this, and if so is there a fix? I'm hoping that maybe it will go away after I shut the stove down later today and let it cool down.