A stove with a closed combustion chamber and a collective chimney

Good morning everyone,
I have a problem, and before I can fix it, I'd like to know a bit about it. I live in a block of four on the 3rd floor. For water heating, I have a gas water heater with an open combustion chamber. In this block there is a collective flue gas chimney, I have a ventilation chimney near the flue gas chimney. Everyone has ventilation chimneys separately.

Now what is the chance to replace the boiler with an open combustion chamber with a closed one? I thought about such a solution but I don't know if it is allowed. I would like a heater that the exhaust outlet and air supply were in a separate pipe, not a pipe in a pipe. And now I would connect the exhaust fumes to the flue gas chimney and the air supply, I would put a pipe to the roof into the ventilation grate and the air would be taken from there. There is still a lot of space left in this ventilation chimney. The only thing that bothers me is whether the exhaust outlet must also have its pipe above the roof?

If this is not possible, is it possible to make a pipe in the pipe and a ventilation chimney?
Regards and I am asking for advice.

If, as you write - it is rather poor chances, because by using ventilation, you will deprive it of a room, they will not give a permit to the exhaust gas where the atmosphere is connected, because you have a fan in a closed one and you can disturb the exhaust gas circulation, and in case of clogging you can push the exhaust fumes into your apartment.
When I installed my boiler (also with a closed chamber), in addition to the exhaust gas and fresh for the boiler, I had to do additional ventilation.
Talk to the chimney sweeps while checking, but the chances are rather slim.

mychaj wrote:

in a closed one, you have a fan and you can disturb the exhaust gas circulation, and in case of clogging, you can push the exhaust gas into the apartment.

Well, I don't understand trgo. In furnaces with an open combustion chamber there is no fan, but the flue gas flows through the exhaust chimney to the outside. So the same as with the fan, only the fan only pushes these exhaust gases.
For now, I have so that if I have closed windows, it draws the fumes from this chimney into my apartment. In windy weather, even with all windows open, it still sucks in exhaust fumes.
I have enough of this because I don't know what to do. I wanted to give with a closed chamber and it would be quiet.

Such connection that you are talking about is prohibited by building regulations
There are installations with a common chimney and connected devices with a closed chamber, but in this case all boilers / stoves must be with a closed combustion chamber - these are LAS type chimneys. You would have to agree with all the residents in one chimney path to replace the appliances and the chimney at once.

It is also forbidden to introduce any pipes, cables or chimney flues into the ventilation duct. Unless you find some spare flue.

massi wrote:

And now I would connect the exhaust fumes to the flue gas chimney and the air supply, I would put a pipe to the roof into the ventilation grate and the air would be taken from there.

The ventilation grille in the kitchen / bathroom just below the ceiling serves to expel "dirty" air outside, and not to suck in fresh air.
You supply fresh air to the rooms through wall or window vents in clean rooms, i.e. bedrooms / rooms. Then the fresh air from the room flows freely through the room, through the slits cut out at the bottom of the door continue to the kitchen / bathroom and goes outside, because this is how gravity ventilation should work.
The amount of fresh air that enters the apartment must be large enough to provide sufficient draft in the ventilation grille and draft in the flue gas chimney, but at the same time small enough not to unnecessarily cool the rooms.
If you only have a hot water heater, at least take care of fresh air while the heater is working by opening the window.
Due to the fact that the boiler with an open chamber takes air for combustion from the boiler room, i.e. in the apartment it will be a kitchen / bathroom and it is roughly 1:10, i.e. 1 m3 of gas burned requires 10 m3 of fresh air, additional fresh and cold air is required air in this room.

With a closed combustion chamber, if you want 2 separate pipes, you would have to bring fresh air through the pipe from the outside, i.e. you give the pipe horizontally to the outer wall, unless you have 2 individual ventilation ducts at your disposal.
Anyway, it requires checking and consent from the chimney sweep, because something may seem to you, but in fact it is different and if you do it yourself, you may hurt yourself and / or others.

massi wrote:

Well, I don't understand trgo. In furnaces with an open combustion chamber there is no fan, but the flue gas flows through the exhaust chimney to the outside. So the same as with the fan, only the fan only pushes these exhaust gases.

Not the same, because in the atmosphere the exhaust gases fly freely, according to your chimney draft and how efficient your gravitational ventilation is. In the case of a fan, such a fan with a common flue gas duct may interfere with the operation of gravity ventilation and affect the chimney draft of the neighbors.
The ideal would be if you had an individual exhaust pipe, then the easiest way would be to put the pipe in the pipe and that's it.

massi wrote:

For now, I have that if my windows are closed, I get the exhaust fumes from this chimney to my apartment

If the exhaust fumes are currently flowing into your hut, gravity ventilation is not working for you and you have a good chance of getting smoked. The higher you live, the shorter your chimney and the smaller the chimney draft, and the flue gases go where it is easier for them.
In my tenement house, when someone set up a gas boiler for heating, the flue pipe had to have an individual + standard, common ventilation duct every 2nd floor.
Generally, you have to solve this problem of exhaust gases, but not only with the help of specialists, because it is a matter of health / life.

Exactly. What do I have carbon monoxide and gas sensors. When I called the chimney sweeps, they said that I should install air vents in all windows. I have a vent in the kitchen and it blows out of it. It is bad in the kitchen, and how to prepare a dinner or prepare something in such conditions? My kitchen window is ajar all the time, and despite that, exhaust fumes sometimes blow from the chimney. As if the exhaust gases did not come out of the top - only on the 3rd floor they would fly into me. The chimney is clean after being checked by chimney sweeps. More than once, with all windows open, it still sucks. And I really have enough of it. I put air vents and I will have children every now and then sick with this cold. In the kitchen, he extracts air through the vents. In a bathroom where there is a toilet and ventilation, it blows.

massi wrote:

In the kitchen, he extracts air through the vents. In a bathroom where there is a toilet and ventilation, it blows.

Perhaps you have too much draft in the kitchen and then the air is sucked in from everywhere, hence the backflow in the bathroom and the exhaust fumes and the air supply from the bathroom grille.
Maybe you have a longer ventilation duct in the kitchen than in the bathroom. It is worth paying attention to whether the roof is even, whether there are any superstructures there to increase the length of the chimney. Sometimes, at the chimney outlet, they install inserts that spin in the wind and increase the draft.
Every detail can make a difference.
Maybe closing the ventilation grille in the kitchen will help, but without measuring air flows with a decent aerometer, it is reading coffee grounds.
Rather, nobody on the forum will help you solve the problem, because it requires a good specialist who will determine the causes and how to solve them on the spot. Only if some renovation is involved, then nobody wants to do it, because the owner of the building does not want to pay for the money until a tragedy occurs.

I understand. Do any of you know any good specialist in this field in Silesia near Czestochowa or Tarnowskie Mountains? Since the chimney sweeps had looked, they went.

If you have a backflow of exhaust gases and your apartment is from the city, intervene that you have exhaust gases in the apartment, since you have a constant supply of fresh air, and yet the problem exists. Applications only in writing with a copy of the confirmation for themselves, because they will ignore you.
If you have an owner-occupied flat, you can also intervene, because ventilation concerns the common part of the property.
Maybe some neighbor has something screwed up that is interrupting the thrust. Sometimes some people install cooker hoods with a fan, which destroys the gravity ventilation in the block.
I am only a Kowalski, so I will not advise you specifically, but the topic is quite extensive and interesting, so you need to be a specialist in this profession who does his best to make the final effect positive.