Difficult bleeding problem with unnecessary auto-bleeder given its location?

[newstarnord]

Hello,

Not long ago I discovered that my vertical radiator from Brico required two bleed screws at the top, when it was connected with inlet and outlet on the bottom ports.

Following that, I had to get some air into the circuit. Once again, at 75 ° it makes strange noises from the heating circulator. If I play with the speeds of the circulator, I manage to eliminate a lot of bubbles which then "go" in the radiators.

However, I have an auto vent on the boiler, ok, and an auto vent in the upper part of the installation after the circulator, ok. Except that the pipe leading to the trap in the upper part is welded to an elbow but not in the upper part of the pipe, but in the middle of this pipe. Can this not hinder the air flow since we are not connected to the upper part of "level 0"? Basically, air needs to go to the elbow instead of going through my pipe to my trap?

Basically we have this:

https://drive.google.com/file/d/1Q1577mQWbpJ-CSCnWyDyuG7i3dzX2vnh/view?usp=sharing

Thank you in advance for your answers

[Flytox]

Indeed for an air purger to be effective it must see air in front of it, and there if the big black pipe is not half-filled with air, it will not purge much.
Where does your big black pipe go on your crobar?

[newstarnord]

Thank you for your answer.

I suspected it was a problem.
The large pipe goes to other radiators, while the small pipe goes to a small radiator only, and to an auto bleeder.
The large pipe does not lead to an auto drain.
I would have to put an auto bleeder on this circuit too, but I don't really want to weld (steel pipes).
I thought of an air separator with a settling pot at a place in the circuit which is in multilayer.

As for the circulator, it seems to me that it easily "traps" the air when there is air in the circuit.
Yesterday, I tested at 70 °; more air in the circulator after having succeeded in expelling the air by alternately modifying its rotational speeds.