water hammer problem

[heatinghelp]

there's water hammer in the central heating system, i've bled all the radiators twice and the banging noise is still there and also there is weird sound sometimes like a almost inaudible whistle coming from near the radiator thermostat valve

any ideas what the problem could be?

 

[gasmarc]

are the rads getting hot and if so adjust the thermostatic valve to stop the noise

 

[heatinghelp]

the rads are hot i'll give it a try and get back to you but thats not gonna stop the banging is it.

 

[gasmarc]

pump could be stuffed

 

[shneld]

Are the TRVs bi-directional?

 

[garrywhite]

Maybe pipe expansion onto joists or boards.

 

[Livvid]

I had the whistle on a TRV, took the head off, pushed the plunger manually then refit the head, whistle stopped, hasnt returned, that was 6 months ago now.

 

[gasmarc]

Happy days

 

[WHPES]

If its the pipes creaking through timbers, melt a candle around where the pipes go through. Usually does the trick.

Same thing for stiff drawer runners - rub a candle on them.