Lisa Jarhead

Ah, this dang thing is driving me crazy; I bought a Diamondback Economy Forge and coated the inside (kaowool and firebrick) with ITC-100. Now that I want to use it, after I light it up and let it warm up on idle, whenever I turn up the propane to get a good heat, one or both of the bells blow out. As is, this thing is worthless....any ideas on what I'm doing wrong? Yes, I'm sure I have propane in my tank so it isn't that, and there isn't any kind of breeze. I have both ends open.