This issue popped up over the last few weeks...at random times during the day, my Harman P68 stove will make this metallic popping sound which seems to be coming more near the burnpot/auger than anywhere else. The best way I can describe the sound is that of a metal flapper on a hot air/oil fired furnace slapping shut against the damper it's attached to. The loudness of the noise varies...sometimes it's soft and barely audible, other times the popping is quite loud that you turn around and want to inspect it. A full cleaning of the stove and fines box reveals nothing out of the ordinary...my only random guess would be the slide plate either acting up or maybe pellets getting stuck (the problem seems to have started after using the Hamers pellets this year, although that may be coincidental)..any ideas on what I should pursue? Thanks in advance!