Can I assume that you have the damper fully open?

Otherwise, your chimney has a bad draft. This can be caused by overhanging trees, a chimney that is not 2 feet higher than anything within 10 feet of it, or just a location where you have natural downdrafts. Has the chimney been cleaned? There could be a birds nest inside.

Installing a stainless steel liner will hugely help your draft if your chimney has a very large flue. Cost, under $1000.

You can also build a large newspaper fire before lighting the wood. This will establish a draft, where it could take several minutes or longer for a wood fire to establish a draft.

Does it smoke all the time?

Not just at start up?

If so, then the draw is bad. The best solution for that would probably be to extend the height of the chimney flue.

That might also help with your neighbors.

If you have not had the chimney cleaned for a year or more, now is the time to do it, and to ask the chimney-sweep what's causing the smoke. I agree that lighting a newspaper in the firebox before igniting the wood, to create an updraft, is a good idea. You might also want to make sure you do not have any exhaust fans on when you burn a fire because that could interfere with the updraft. If your house is very tightly insulated, You might also want to open a nearby window just a crack to help the updraft. Also, make sure you use well seasoned dry hard wood.

If, after trying all these things, the problem persists, then the only corrective measures left are pricey. You may need to make the chimney higher so it does not pump smoke into your neightbor's place. Of you may want to consider installing a gas fired direct vent insert. They are terrific but costly.

I'm glad to find this link. We've NEVER had this problem and its happened 3x's this year. You light the fire and suddenly its coming back into the room - a huge amount of smoke. I quickly open the door and "fan" and the smoke goes out the door and back up the fireplace. Obviously the damper is wide open. I will say when this did occur it was very cold outside - did that have anything to do with it? Frankly I'm scared to have another fire because of the smoke. The wood we are using is hard wood oak.

You may want to check the entire installation. The blower should not affect the burning characteristics of the fireplace.

Normally, the blower forces air around the exterior of the firebox and a heat exchange takes place. In your case, it sounds like the blower may be forcing air into the firebox. That needs to be looked at.

I don't think you should use your fireplace until it is checked out by a pro.

As a woodburner on a daily basis for 33 years, I'll say this: If I do not make a newspaper fire with a cold chimney, I WILL have a house full of smoke.

And the colder the chimney, the less the draft and all the more reason to pre-warm the chimney.

I used to heat with wood, and currently burn it for ambiance. I always twist a few sheets of newspaper together, light it, and hold it under the chimney until it starts drawing. Once is does, I light the wood fire, which I lay with a newspaper starter below the kindling.

Wectra should be responding with some basic information, such as whether they do or don't preheat the chimney in a similar manner.

Starting a chimney fire with some twirled up newspaper is extremely important. The reason: The cold air in the cold chimney will tend to drop down into the fireplace. The natural air flow is in the opposite direction to what you want. Lighting with newspaper will warm the air in the chimney and reverse the direction of the air flow and should correct the problem.

HOWEVER, IF YOU HAVE NOT HAD YOUR FIREPLACE CHECKED AND CLEANED IN OVER A YEAR, YOU SHOULD DO THAT BEFORE YOU USE IT.