New install! Can I run class A through existing steel chimney?

[Lutsen55612]

Hello everyone!
I love this forum and have a 2 questions.
We are replacing an old inefficient fireplace with an Ambiance Elegance 42.
The current fireplace has a 10” flue that runs up through a wood framed chimney system that is lined in drywall.
Can the class A go through the existing 10” flue and vent outside Or do I have to remove the old 10”?
The other question...
Can I vent our boiler (radiant heat) in the same chase as the fireplace?
For clarification...it would be a PVC 3” pipe that would be ran separately and not in the 10” flue.
Cool and thanks!

 

[webby3650]

Just remove the old chimney pipe. It’s most likely being supported by the old fireplace anyway.
The pvc vent can share the chase with your new chimney, that’s not a problem. Just get it as far away from the wood burning flue as you can.