I've got a Hearthstone b vent propane fireplace / stove. I've got 4" flex vent inside a 6" metalbestos chimney. The 4" goes all the way to the top of the inside of the cap. - 3". It was 30 deg last night. I lit it off, it would not vent, clicked off on safety after2-3 min. I got advice from "the gasman" last January about putting the flex vent inside the 6" mb. He said the mb was too big, it would not get warm enough to draft. That sounds logical. It's a great LOOKING stove, but if it won't draft, it's just a boat anchor. Any ideas out there in gas land?
Thanx,
Ken in Vermont
Thanx,
Ken in Vermont