radiator/pipe noise

[joebilge]

hi, i've just moved into a new house and am having a bit of central heating trouble. Once the central heating has warmed up a noise rather like a car idling appears, localised around an upstairs radiator. I bled the radiator in question which appeared to be mostly air but the noise is still there. Could there be air trapped in a pipe around it maybe? and if so how do I get rid of it? if not, what else could it be?
Cheers very much,

joe

 

[spacethegas]

whilst it is making the noise remove the thermostatic valve head.

does it stop ?

 

[John506]

Sounds like TRV Chatter.

Do what spacethegas said, if it stops you need to replace the valve with a bi-directional TRV (allows water to flow either way) it should have an arrow on it pointing each way.

If this is the case, the noise is the TRV trying to close down, but the water is pushing it back up, then the part that is closing down will kinda vibrate up and down really fast and make a terrible noise.

 

[joebilge]

Sorry about the late response (no internet in new house yet). The radiator has the regular old style valves not TRV. It doesn't make much difference if the radiator is on or off; its almost as though the vibration is coming from the pipe under the floorboard (parallel with the radiator). The noise only occurs after the water has heated up and still occurs even if all the radiators in the house are off, but is still localised around this one radiator. Sorry about this conundrum.
Cheers, Joe

 

[spacethegas]

i got the impression it was a new house.

i assume it is not as i would expect all radiators upstairs would had trvs.

 

[joebilge]

Sorry, I meant new for me. Its a 1930's semi.

 

[spacethegas]

in that case it is very difficult to say without witnessing it.

if it is a regular click click click it may be caused by expansion. but this would tend to start when heating comes on, then stop, then start again as it cools.

is it quiet when just the hw is on ?

what sort of boiler, system controls etc. ?

 

[joebilge]

The CH boiler is separate to the hw so it doesn't affect it. The noise occurs once the heating has been on for about 20 minutes. Rather than a clicking its more of a hum, building up to a low trumpeting. is it likely to be some kind of trapped air somewhere?