What to do if a wrong chimney has been installed?

In our new building, the architect planned a chimney because we wanted a wood stove in the hallway. It was very clear that it had to be an airtight stove, and that the chimney needed an oxygen supply. The mason took care of that. The stove fitter connected the airtight stove. During the first test run today, it was found that the stove did not burn properly because it was not getting enough oxygen. It only burned well when a) the flap was open or b) the shaft on the opposite wall was open. The stove fitter tried to shine a light from below into the chimney through the shaft and found that the flue pipe almost completely filled the chimney with hardly any space for air supply. He suspects that the wrong chimney was installed. Bingo! So, an immediate call to the builder who did the masonry work (this evening just before 7:00 p.m.). He wants to first check tomorrow in his documents what type of chimney the building material supplier charged him for.... The stove fitter also knew a case where the masons used so much mortar during the chimney construction that there was no more space for air supply from above. It had to be very elaborately poked around through the roof with something to free it again. Anyway. Big mess!..... I’m afraid we now have to take the oxygen supply for the stove from the living spaces, which is, of course, really bad in a newly built, fully insulated house.

Does anyone have experience with this?

What is stated in the [Bauleistungsbeschreibung] or in the contract on which the bricklayer/construction contractor has worked?

Big mess!..... I’m afraid we have to take the oxygen supply for the stove out of the living rooms now, which of course is really stupid in a new completely insulated house.

No, if you ordered it with outside air supply, it just has to be changed accordingly. There are different solutions for that. It’s annoying but not a reason to make any predictions yet. Keep your eyes on the goal and not on possible problems; let others solve those.

Extracting the air from the living space will also not work because a well-sealed house does not provide enough air for inflow. Is the stove located on an exterior wall or is there a basement under the stove?

what is stated in the construction service description or in the contract on which the mason/construction contractor worked?

These were all verbal agreements. After a sleepless night, the construction contractor was with us today. He could still clearly remember that he unpacked the chimney together with the mason and then called the building materials supplier again to confirm whether it really was a chimney with ventilation. The building materials supplier, with whom he has worked for 30 years, expressly confirmed this to him at the time. The construction contractor went to the building materials dealer early this morning, and the latter then checked again or contacted the field service employee to find out that the chimney manufacturer had changed their model. Everyone acted in good faith. During the shell construction phase, the stove fitter was also present; he noticed nothing. The chimney sweep was also there; he noticed nothing either.

No, if you ordered it with external air supply, it has to be changed accordingly. There are different ways to solve this. It's annoying but no reason to make any predictions yet. Keep your eyes on the goal and not on possible problems; others should solve those.

How is that supposed to be changed? The house is finished. We want to move in next week. What solutions can you suggest? The builder had no idea so far. We also cannot install a pipe leading outside. The stove stands in the hallway against an interior wall.