I have a Ventis HE1240 insert. I had it installed about 3 months ago, it's been working great. Except the last week we've been getting pretty steady rain and now when I start a fire when the door is first cracked, I get a ton of smoke pouring into the house. This wasn't happening previously, and I'm using pretty much the same wood (same big wood pile.) The only things I can think of is the change in weather or I have put some good size logs into the insert. Could the chimney flu or exhaust somehow have gotten plugged on the insert? Any tips are greatly appreciated.