Radiator

[Kazal]

I have one radiator that was installed 2 years ago that constantly needs bleeding - like every day. On the valve where you bleed it there is a small hole (nipple type) and the air comes out through there. None of the other radiators have this. People tell me that there is always one radiator that needs bleeding more than others and there should be no problem. However I did not have this problem before this replacement was installed. Also am I right in thinking that the constant bleeding is causing the inhibitor to be weakened. I know nothing about heating systems. Can someone please advise.
By the way I do not have a combi boiler and I have an indirect system.

[buildersmate]

No bleeding doesn't change the inhibitor to be weakened - not if you just remove gas and don't lose litres of water every time you do it.
Constant need to bleed is a sure sign of one thing - gas is getting into your system constantly. This is a bad thing and it shouldn't happen. It (nearly always) comes from one of two sources:
1) It isn't air at all but hydrogen gas - the product of corrosion inside the radiator because the inhibitor isn't concentrated enough
2) Air is getting in through the indirect tank - constant sucking of aerated water from the tank - then pushing it back up to the tank again.