Air supply chimney stove base plate pipe

Hello everyone,

at the time of construction, we had a supply air duct for a fireplace installed in the floor slab. The pipe outlet is next to the chimney, see picture in the living room (not on the exterior wall). In the piping plan, see picture, a pipe is now drawn that leads outside. Outside is the pipe outlet with a kind of cap, see picture.

Could this be the supply air pipe?

Best regards

Addition:

We are somewhat worried that we may never be able to install a stove because we possibly missed the [air supply].

In the floor plan, I do not see a supply air duct, only wastewater pipes. I would remove both covers or the plug, then smell to see if wastewater pipes are connected outside. And then call in and a second person listens at the other end.

Thank you for the feedback. It already smells like sewage. We just wonder what sense it makes to have a sewage pipe in the middle of the living room next to the chimney…. Unfortunately, it can no longer be reconstructed afterwards how that could have come about, because it was always clear that a wood stove was supposed to go there.

If there are wastewater pipes in the living room, remove the strange plug and put a sealing cap on. In the outdoor area, also put a sealing cap on, it is needed again and again (empty the cistern, flush the pipe and clean it in case of blockage, as a motorhome drain, etc.)

We are just wondering what purpose a sewage pipe has in the middle of the living room next to the chimney….

Maybe it is a condensate drain?