Im sure its normal as the metal heats up but my f2400 will make loud tining,cracking,bell type noises till it heats up into the 500+ degree range. I had a large old buck stove with double steel welded walls , that was very inefficent so I replaced it with the 2400. The old buck didnt make a sound but boy did it eat wood lol. Im sure its normal for the metal to strecth as it heats up and it is a much smaller stove but I was just wondering if anyone else with a f2400 or similar stove makes the same noise as it gets to higher temps. The stove runs great so far and it is burning alot less wood and giving out good heat for a 3 bedrm 1200 sq ft home.. Glad I purchased the 2400 instead of the 1100 as the dealer suggested. Temps running closer to stove area in front of house in the 80s with rear bedrms at 67. Temps outside 18* nights 33* days. Snow 1-4" comeing thurs and sunday 1-6" ,,already had some on ground .Glad I upgraded when I did....Thank You... Mario in Hopewell Va...MERRY CHRISTMAS AND A HAPPY NEW YEAR....