Any of ya Fella’s ever have your furnace or boiler bark back at ya? This morning I had a roaring fire going. Then I shut down my air to the minimum and started to see a little smoke coming out of the air dials, then two big puffs smoke more like snorts. I figured I just had a back draft on the unit? The chimney had good draft. Outside It was kind of windy. I figured I shut the feed air down too far and there was such a good draft that it started to pull a vacuum on the furnace and it lit off?