Water Gurgling in Sink & Shower Tray, Paddling Pool Overflow, Bathroom Renovation & Pipe Unclogging

Hello.
After 3 years after the renovation of the bathroom and toilet, there was a problem, namely there is a bubbling while the water flows from the washbasin - the shower tray, etc. It looks like that when the water flows from the washbasin, it gurgles in the washbasin and the water appears in the nearby paddling pool. It seems as if the water wanted to go out of this paddling pool. The running off is well done - why would it be bad if everything worked for 3 years. The new drainage installation has been attached to a piece of starek which is glued vertically. In this riser there is also a water outlet from the toilet but nothing is happening there. Yesterday a specialist was called to push this old piece of pipe because there was a suspicion that it might be clogged. He put a 5-meter-long spring in, twirled it, slid it and left. After all the action this am - gurgling gurgling. It looks like some air - the pressure in these pipes was and was circulating in this water - I don't know how to explain it. The restaurant is on the 5th floor and it is like a half of the building and the first zone because it is an 11-story building. There is a problem somewhere, but I cannot locate it. All drain siphons - pipes with a cross section of 50 mm.

What could be the reason ?

Venting the riser unobstructed?

zetdeel wrote:

Venting the riser unobstructed?

How to check it? How to suggest that the administration check it.
Will the gurgling effect when the riser is deaerated only be with me due to the fact that it is an apartment that ends the first division of the building?

I would check the patency behind the place where the drains from the sink and the shower tray connect.

Quote:

when water flows from the washbasin, it gurgles in the washbasin and the water appears in the nearby paddling pool

. If it cannot flow into the main pipe, it flows out of the tray!
Link .

Qbuś wrote:

I would check the patency behind the place where the drains from the sink and the shower tray connect.

Quote:

when water flows from the washbasin, it gurgles in the washbasin and the water appears in the nearby paddling pool

. If it cannot flow into the main pipe, it flows out of the tray!
Link .

The pipes are completely empty - even the water in the washbasin in the toilet, which is very close to the vertical, flows very slowly - as if some air was pushing it the other way.

It must be the "sparrows" made a nest in the venting, Or someone who mixed up something and will not admit it.

Qbuś wrote:

It must be the "sparrows" made a nest in the venting, Or someone who mixed up something and will not admit it.

The problem with venting - that would be correct and the latter part of the answer
"Or someone who mixed up something and won't admit it" - where, in what place - I put the water installations myself.

Quote:

The new drainage installation has been attached to a piece of the old one that is glued vertically

Here I would be looking for the cause .

Qbuś wrote:

Quote:

The new drainage installation has been attached to a piece of the old one that is glued vertically

Here I would be looking for the cause .

The old piece is about 70 cm, which could not be replaced because it is glued to the main pipe. Yesterday it was pushed by a spring. It climbed 5 meters - and it was scratching the back of the neighbor downstairs.

It's hard to advise anything wise without seeing this installation, if you have the opportunity and willingness to disassemble it and check it again. Maybe the "drops" were wrong, maybe something was left in the tube, maybe, maybe? Maybe some sketch or photos?
Ps. What ? is the main pipe?