Hello!
I will try to make the story short.We bought a two story house a few years ago.The heating in the attic was done in a very interesting way- two baseboard heaters (with bleeders)connected to the radiator in the foyer:confused:. Well,we have had problems heating the attic since we bought the house and the reason for it is the way the connection is made obviously unless we crank up the heat up to 80 degrees or more.This way is unacceptable and very costly to us:(.
I bled the radiators in the whole house. The radiator in the foyer had some hot water in it at the time and it was cooler on top,because of all the air in it.
The question now is not about getting heat to the attic at all ,because we have given up this a while ago,but about the radiator in the foyer which is completely cold while the rest of the radiators are hot.:confused:
Should I consider it not repairable at this time while the whole system is running still or it can be fixed in some way,so we can get heat at least in the radiator in the foyer,which is the only one for heating the stairwell. I have fixed many times different heating problems around the house and have had them fixed ,but this now is not making any sense to me:
The pressure at the boiler is 15lbs.The temperature is controlled by electronic thermostat and it is running perfectly by the schedule.The circulator pump is working .There is hot water going to the radiator ,but it doesn't go in it.The shut off valve is fine,because hot water enters the radiator while I bled this radiator again today and it is cold as the weather outside.;)
I hope there will be someone able to give an advice and help us!
Thank you in advance for the attention!

Was the system/pump running when you attempted to purge air? If so, try it again with the pump off.

The attic is where you should concentrate the bleeding. In fact the attic should have automatic bleeders. Air will rise in the system to the top eventually. If the hot water will not get to the attic area that is the problem with your situation and no matter how much you bleed the foyer if it is connected to the attic the air in the attic will stop the flow. Replace the attic bleeders with float type auto bleeders to start and give them a chance to get rid of the air lock situation. To help this out you can run 20 pounds in the system with no problem since the pop off safety is at 30 pounds.

You can also try a power bleed but that should not take place till the auto bleeders have had a chance to work.

Lets assume the air is bled as you indicated first it was air locked then just cold. Lets also assume the foyer radiator was fed originally on its own circuit from the boiler because none of the other radiators are cold. And I assume you mean large cast iron radiators. If you are the pervious homeowner and decide you want to heat the attic you decide to come out of the foyer radiator and then back to the boiler piping. Water takes the path of least resistance. Radiators are usually piped in larger diameter piping than the typical 3/4" baseboards. So the boiler is trying to circulate on a call for heat. It is difficult to go through the radiator then up 2 floors and back(head pressure). Much easier to circulate through larger piping and shorter runs on the lower floors. So getting the foyer radiator to heat means it needs to flow which means it needs to go up to the baseboards and back. You can try shutting down the flow on the other radiators in the house causing more restriction on those and more flow to the attic. There may be balancing valves on the boiler piping as well. An you may get foyer heat but forget the attic. If your thermostat is in a room with a radiator the radiator with its mass of cast iron and filled with 180 degree water will radiate for much longer period than a baseboard which has little storage mass. So the attic will cool much faster. The baseboards should be on their own zone to heat evenly.

If the attic terminals are not heating, they may be at risk of freezing and rupturing. Just ignoring them may not be wise.