Central Heating Issue: Heaters Only Heating at Top in Kitchen, Room 2 & 3 - One-Riser System

Hello

I have a problem with central heating at home.
Namely, some heaters only heat at the top and the bottom is cold.

Painted in drawings, but better than nothing you can see the bottom of the house consisting of the Entrance, Corridor, Kitchen, Bathroom, 3 Rooms and pantry - but there is only a tube going to the radiator at the top of the house, there is a radiator only in the Room and bathroom.

The basement with a stove and pump is under the Corridor and Room No. 1. From it the first copper pipes come out next to the radiator in the corridor and there it is distributed in two directions, namely:
Kitchen - Room upstairs
Corridor - entrance - Room 1, 2,3 for the bathroom, there is a floor and one small suspended radiator and from it goes a pipe up to the bathroom, to its radiator.

And now the problem appeared in Room No. 2 and 3 and in the Kitchen.
The rest of the heaters heat up completely
I will add that it is a one-riser system and the pump is on its return.

Have any ideas?
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Did it come and announce?

If there are thermostatic heads on the radiators, it is normal that the radiator can only heat from the top because if the set temperature on the head is reached, it throttles the flow so as not to overheat the room. For example, if we set the number 3 on the head, which should hold about 20 degrees in the room, the radiator can turn off completely and there is nothing wrong with that. If the room is not more than 20 degrees and the radiator is cold, then we can only start discussing the problem and possible solutions

There are some thermostatic heads next to them but without setting 1-5 only a dash with an arrow from - to + and they are unscrewed.

In room No. 1 there will be 22 degrees and in room No. 2 e.g. 18

Added after 1 [minutes]:

There are no air because water immediately flies at the vent. Only where the air flies for 2 or 3 seconds is the heater at the top in the bathroom once every 3 weeks so it has