What to do if a wrong chimney has been installed?

If the chimney sweep approved it with praise, you shouldn't need to open any flaps or place a plant in front of it. If the stove doesn't get enough air, the chimney can't draft properly either. So much can go wrong. Several people have already died because they underestimated the dangers. Remember, we're talking about fire inside the house.

When the chimney sweep came, the stove wasn't on at all. He looked into the flaps, shone a flashlight inside, and found everything fine. Is a normal stove – that is, a room-air-dependent stove – forbidden in a new building? Yesterday during the test run, the chimney only drew properly when a) the stove door was just ajar or b) the air flap in the living room was open. When both were closed, the fire barely developed; everything smoked. So the chimney didn’t draw.

Is a normal oven - that is, one dependent on room air - prohibited in a new building?

No, of course not. Plus words and characters...

lus words and characters...

I don’t understand the last line now.

The last line I don't understand now.

you stupidly have to type at least 5 words and 30 characters here, mandatory. Stupid. ;)

Is a normal stove - that is, a room air-dependent stove - forbidden in a new building?

No. But have you ever wondered why you don't have one or it wasn't planned?

When both were closed, the fire barely developed, everything smoked. So the chimney did not draw.

Ahh, here seems to be the answer. Gases flow through a stove. It sucks in oxygen or air for combustion and emits exhaust gases again. For this to work, the flow of gases must be ensured. The drive is the chimney. As it "draws," that is, exhaust gases are drawn upwards and outwards, a negative pressure is created so that the stove can suck in air. This is supposed to happen entirely through the chimney in your case, since your house is probably very tight. Since there is no access for fresh air, it must suck in elsewhere. Revise flap or stove door. This may work as a crutch but can be risky if the flap or stove door is accidentally closed or oxygen cannot flow sufficiently into the house. In the worst case, smoke gases enter the building, which smells unpleasant and is unhealthy or even worse, carbon monoxide, and you all won't wake up anymore. Please talk to the chimney sweep about this.

The stove has thus been approved and works with the intake air flap open. That already sounds quite good. Apparently, you did not get a room-air-independent stove, so conversion measures and proposals (such as a ventilated system) are unnecessary. Like in your case, this is also how it is solved in our "Kinderapartments" - intake air comes from the room. The chimney sweep determined that the room volume matches the stove size and the approval is given. However, the intake air from the intake air flap built into the stove is sufficient. That the wood stove cannot reach temperature with the flaps closed and produces a lot of smoke gas is due to the nature of the matter. If, on top of that, "bad" - too damp firewood is used, it becomes very smoky in the stove. Where is the problem now?