Fireplace smell when Central Air runs

[briora]

When my A/c runs I there is a strong odor of a fireplace ash / fireplace smell. It's comming from the fireplace area since it only smells in the living room that the fireplace is in. The A/cis in the basement and the fireplace on the first floor. I checked the damper and it's fully closed.

Not sure why I am getting this fireplace smel, I did,t happen last year. Over the winter I did burn in the fireplace about once every 2 weeks. I am concerned about why it is flowing in the house, shouldn't it go straight up the chimney. I hope there is no issue with dangerous air flowing back in the house. Is this common or should I be concerned?

Thanks,

Brian

[HayZee518]

the air conditioner is creating a negative pressure in the ducting system in the house to circulate conditioned air. its pushing the colder air into the house and "sucking" the heat laden air into the a/c system. any air leaks in the house will be in this "convected" air of which the chimney is a direct source to outside air. any odors within the chimney are picked up and re-circulated in this air loop. other than the stink I wouldn't worry about any "gases" that are harmful. there's no combustion in the fireplace.