We had a new central heating system fitted when we redone the whole house about 4 month ago. It included new boiler, pipes and radiators. Right from the begining there was a leak in one of the soldered joints but that got fixed. What I have been noticing since then is that the bathroom radiator which is also in the highest place is slowly collecting some air. By slowly I mean 4-5 top vertical bars of the radiator become cold over a period of 1 month. The pressure in the boiler shows as normal and it only drops if i bleed the radiator. I have not noticed any leaks and checked the connections around the radiators. It is only that one radiator that collects the air, all others don't even have an inch of air.
What can be causing this? Is this expected to happen and I just need to keep bleeding it every now and again?
What can be causing this? Is this expected to happen and I just need to keep bleeding it every now and again?