got new combi boiler put in one year ago.been fine up till now.hot water fine and rest of rads working fine,but livingroom one has been rattling,and heats great for first 30 to a houre.then goise warm at bottom to cold,then goes cold.when i turn the trv,the rattling goes through to other rooms,then when i turn thay vallves it stops.pressure is fine on boiler and all other rads are piping.noise has been getting worse like viebrating 'had to turn off boiler to stop it the other nite.could any one give me a bit of help,thanks. :?
This sound like it's a vibration caused by the water being pumped round by the boiler and being forced through the narrow gap as the valve closes. If there is air in the radiator, the noise could be worse. The fact that the radiator is cold at the top is a clue that there probably is air in it. Use a bleed key to open the bleed valve at the top of the radiator half a turn, holding a cloth underneath to catch any water that escapes. You will probably hear the hiss of air - when you start to get water out, turn the bleed valve off again.
Ideally, you should gave a room stat in a room with no TRV on the radiator. This would shut down the boiler when the house is up to temperature. If there is no room stat, a quick fix is to open one TRV fully (usually in the bathroom) and adjust the temperature using the stat on the boiler.
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