Banging pipes continue

[julia34]

Hi

I wonder if you could help me. We recently add radiator into a bathroom and when we start have heating on we noticed a loud banging noise from the pipes. The noise sounds like pipes "twanging" and banging. This banging occur from a start when the CH comes on and when cooling down. The noise we are experiencing upstairs of the house

The Boiler is a Worcester Greenstar 255i/30Si
The CH and hot water do work fine and heat up quickly, (it does not make any noise when the radiators hot).
What we did:
-We insulated around the pipes so they sit tight
-We did bled the radiators
-when we drop the pressure from 2 to 1.5 bar the noise comes but took it longer to get the noise, a ticking noise (I assume expansion) and every now on loud bang from pipes
-sometimes when we turning the radiator valves from ( max to *) we get loud click , that happened upstairs and downstairs of valves
-couple times when we had air comes from a radiator even we did bled the radiators before

Few days ago we took a floor board out to insulated the pipes around and where they touch the main cold water pipes.pressure stayed 1,2 bar
It was sounds that the noise was more quitet and less you could hear it. after 1 day the noise come back.the banging is moving from one room to another, the banging only appearing upstairs.
In bathroom radiator sounds like water is moving every now on.

Can anyone help? - do I have air in the system? – valves problem?

Thanks everyone in advance.

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[DAZB]

Sounds like you have water hammer, see if this explains it better for you :
http://inspectapedia.com/plumbing/Water_Hammer.htm

The small part you need can be purchased at any plumbing or builders merchants inc. the usual big ones we all know.

 

[Terry lambert]

Do you have one radiator without thermostatic valves and are the valves on this radiator open?

 

[julia34]

One radiator without thermostatic valves

 

[julia34]

I don't know if the valves are open

 

[Terry lambert]

Does that rad get hot ?

As an experiment you could remove a thermostatic head off of one of the valves up stairs, then see if the banging goes away. With most models the heads come off by unscrewing the large nut at the base of the head

Cheap TRVs also chatter when they are closing down onto the pin as the room gets upto temp ( they work on air temp )

 

[julia34]

The rad get hot and banging stop when they very hot, I would say the bang you can get every once in a while

 

[julia34]

The noise appears when the radiators start heating up.it was worse before we insulated the pipes

 

[Terry lambert]

It could be th pipes expanding, but I still suspect the TRV heads chattering.

Try removing all of the TRV heads upstairs and see if the noise goes away

Are the TRVs upstairs on a low setting?

 

[julia34]

Only one is on low setting, always been, thanks

 

[julia34]

I will try to remove the try heads

 

[julia34]

I probably sound boring now but I forgot to tell you that in bathroom I have to bled the radiator , that happening every week and I don't know how the air gets into
I hope that helps to resolve the problem too,

 

[mcmoby69]

the radiator you added, was it a towel radiator with an inline thermostatic valve?

did you check the valve before you fitted it to see in what direction it should be fitted?

there is usually an arrow on the thermostatic valve and the flow of hot water must go in that direction. that means you will need to identify which of the pipes gets hot first when the heating first comes on.

the valve will need fitting on the flow pipe with the arrow pointing up or on the return pipe with the arrow pointing down. unless of course its a reversible one.