Why the extra flue for this fireplace?
I have a question about direct vent fireplaces venting and sealing behind them. I have two direct vent fireplaces in my home. I have one in the basement and one on the main floor. Both vent out the side of the house. Picture attached. I also have a flue out through the roof. Why do I have a flue out the roof if I have direct vent fireplaces? Also I know there isn’t insulation behind the fireplace because when I look through the giant hole for the gas line I can see OSB. Few questions, is there a way to know if I can remove the Vertical flue? Maybe the initial plans called for a normal fireplace and then they upgraded the fireplaces? What are my options for insulating behind the fireplace? I can feel air rushing in the hole where the gas line enters.
Check the attachment for a picture of the back of my house built in 1996.
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