Hello Forum,

I've got a 2-flue chimney, with fireplaces in my basement, and directly above that on the 1st floor. 1st floor is in use as a wood-burning fireplace. The basement fireplace has been closed up, and the flue has been used for the past 40 years as exhaust for the boiler.

I'm replacing the boiler with a direct vent unit which will be vented directly to the side of the house. I will no longer need that flue for the boiler. We can close up the hole in the side of the chimney.

Can I re-open the basement fireplace that used to be served by that flue, and use it? I don't mean do the work myself; I'd have a professional do it. My question is more based on code (I'm in NY state) and the safety of such an arrangement - are dual-flue chimneys up to code in the modern era, or are they just grandfathered in if they are still working?

It would matter because we would be re-opening a fireplace that's already closed, so it would probably require a permit.

Thanks in advance,

Nelson