I am living in an apartment in Belgium. My bedroom radiator is basically useless; it's about 1m long but only the left 10cm ever gets warm.
I have been told to bleed the radiator by opening the valve and letting the pressurized system fill the radiator with water, pushing air out until the water starts leaking out of the valve. This, however, is not working for me. I have tried leaving the valve open for weeks and nothing ever changes. I have also tried opening and closing the main radiator valve. When I close it, I hear a hiss from the bleed valve. When I open it… I also hear a hiss from the bleed valve.
I suspect that I have somehow actually worsened the problem as when I first moved here the radiator was maybe 50% operational; now it's 10%.
Is it possible that I am allowing air INTO the radiator rather than letting it escape? Is there some magic combination of "open bleed valve, open radiator, close bleed valve, close radiator" that I need to try?
I have read other DIY sites on the net but basically they say what I've already tried, or talk about turning off the central heating system which is not possible in my apartment building.
I have tried contacting the landlord but it's a monumental task to get her to take any action. That is a separate issue I'm dealing with; right now I just want to feel comfortable.
My fingers are freezing making it hard to type, so I'll wrap this up 😀
[UPDATE]
I managed to get it working, but I think it's more magic than anything. A combination of turning the radiator on / off/ leaving the valve open / closed and it started working again. For the moment I simply vow not to touch it anymore!
Best Answer
To get your landlady interested, point out that the radiators are filled with moist, warm air, and that the system is corroding from the inside, shortening the life of the radiators and clogging the boiler with rust. That means the boiler's life is being drastically shortened and may soon cause a massive expense. Fixing it now would be much cheaper than fixing it later. The question is, is she greedier than she is lazy?
As to what's actually the problem?
It seems to me that your apartment's system wasn't being replenished with water. Opening the radiator bleed valve wasn't doing anything because there was no additional water available to replace the air.
Central heating systems come in two flavours -- open vented and sealed -- and each refills with water in a different way. In an open-vented system, there is a tank at the highest point in the system, that uses a ballcock to fill up with water: see this diagram at diydata.com. The ballcock is in the feed and expansion tank. If the ballcock isn't operating correctly, the feed and expansion tank doesn't fill with water, and so no extra water will be available to fill your radiator. The ballcock could be stuck, or it could have been tied off so that some work could be done, and never untied. If you've got that kind of system, the fix would be to get the ballcock moving freely again. Is there some kind of maintenance area you could check out?
Alternatively, it may be a sealed system; there's another diagram showing that. These systems are filled up with a tap -- see the 'filling stop cock' in the other diagram. Normally, you'd check the pressure in the system every few months and use the filling stop cock to make sure the pressure is high enough -- say, 2 to 3 bar. Again, this will probably be very close to the boiler itself and so would need access to your building's maintenance area.
My guess is that it's a sealed system, and that the internal pressure has dropped right down to atmospheric pressure on the fifth floor. Lower apartments won't be suffering because gravity gives them more than their fair share of water, so most tenants won't suffer. However, any rust generated in your radiator will sink down into the system and clog it for everyone.