Help removing Austroflamm insert

Hello

I recently bought a house with an older Austroflamm interga insert. It has a 1991 Test date on the certification sticker, but I do not think the insert is that old

My question is - How do I get the surround metal around the insert removed so I can clean the stove's fans and motors. Or maybe I slide the insert out with the metal in place? The surround metal almost seems to be concreted around the edge of the original fireplace opening.

The unit works great, but after seeing the pictures on the forum of birds,nuts, and stuff inside these inserts I want to make sure the stove in in good safe working condition. I also would use this opportunity to check the flue insert piping

Any guidance would be appreciated

Thanks,
Bobby the new pellet stove owner.

Thanks for the information.

I saw the screws for the top piece in the hopper, I did not notice the ones for the sides. I will have to look again after I get the hopper more empty.

Do you slide your stove out to clean? Or just clean in place?

Bobby