Radiator’s valve hammering

[zzag]

As you can see my heating system upgrade saga continues. Current problems is that valve on one of my rads (in the bathroom) is making what can be best described as ‘hammering’ sounds (10-15 sec apart) when it heats up and produces more of a loud ‘crackling’ sounds when cooling down. As far as I can tell the sound is produced in the top part of the valve where it connects to the pipe. This is one pipe system using Giacomini valves (pls also see attached picture) and it is the only valve that is doing it. (Well, there is another one that makes some noise but only once or twice which is tollarable.)

I would highly appreciate any suggestions what might be causing this and how it can be remedied.

Cheers!

 

[stevetheplumber]

flow and return reversed and valves one way only

 

[zzag]

RE: flow and return reversed and valves one way only
>>>Thanks, Steve, but would not this render valve/rad non-operational? As it is now - valve is working (alas - with some noise), rad is heating up and other rads in the chain (this is one-pipe system) are also working. Any other possiblities?

 

[traineedrip]

it would still let water through. how does it compare to the other rad valves?

 

[wnjswozo]

rad would still work,but because one way thats what happens ie vibrates,drain it down swop vavle to other side,or replace with two way trv

 

[so-solar]

sounds like the valve is actually worn out, surely if the flow and return were switched other rads would be doing the same?

 

[stevetheplumber]

RE: flow and return reversed and valves one way only
>>>Thanks, Steve, but would not this render valve/rad non-operational? As it is now - valve is working (alas - with some noise), rad is heating up and other rads in the chain (this is one-pipe system) are also working. Any other possiblities?

just looked at the picture these valves are not reversable you can tell by the arrows on them to check direction start from cold and see which pipe gets hot first it should be the one with the arrow pointing up

 

[zzag]

just looked at the picture these valves are not reversable you can tell by the arrows on them to check direction start from cold and see which pipe gets hot first it should be the one with the arrow pointing up

I can double check tonight but I am pretty sure the valve is installed correctly as otherwise hot water would not reach other rads in the chain (one pipe system). I am also pretty sure that the noise is produced in the upper part of the valve - pls see attached picture. Provided that valve is facing the right way - what else could possibly cause the noise and how can it be remedied?

 

[stevetheplumber]

I can double check tonight but I am pretty sure the valve is installed correctly as otherwise hot water would not reach other rads in the chain (one pipe system). I am also pretty sure that the noise is produced in the upper part of the valve - pls see attached picture. Provided that valve is facing the right way - what else could possibly cause the noise and how can it be remedied?

sorry from the first pic i assumed it was a thermostatic valve having seen the full set up i can honestly say i havent a clue what it is or does

 

[zzag]

Thanks Steve. What if we forget about this being one-pipe system with weird valves and only look at the fact that the pipe coming out from the top of the valve is making crackling noises as it expands when heated or shrinks cooling down (pls see circled section above) what would be the cause and remedy for this under normal circumstances?

 

[wnjswozo]

take the trv head off valve and leave it a fw days running normaly see if it makes noise,these twin entry vavles are a pain

 

[bobpape]

Two things worth a try.

Take the valve apart and wedge the clapper so it dosent move at all.

Try varying the speed of the pump and check the differences

 

[stevetheplumber]

cn anyone explain how this valve works with three pipes one large and two small which are marked in and out ??????

 

[zzag]

Attached is quick and dirty diagram of water flow in one-pipe system using this type of valves. It is abomination that one-pipe system has been installed in a home but there is nothing we can do about it at the moment.

As for crackling noise - there is a slight chance that specifics of the valves are playing some part in noise but I would be more inclined to think that noise is produced by pipe-to-top-of-the-valve joint (or pipe itself)which should be quite common and thus must have few a relatively simple causes/solutions. Anyone has any ideas so that I can get back to the plumber and get this fixed before x-mas?

 

[bobpape]

I recon the valve contains a threaded plug that if adjusted by screwing it in does two things..it reduces the flow from the rad and at the same time increases the flow through
the valve,
I would therefore suggest that as it seems the only moving part is the plug, the only thing that could be wrong with the plug would be the thread too loose a fit

 

[zzag]

Thanks a lot, Bob - this is something worth investigating. Could the chrome pipe itself do expansion/contraction and rubbing against valve or it is not possible without a leak?

 

[bobpape]

Thermal expansion contration only becomes significant in long lenghts of pipe say 10m
upwards, that is not to say a short length does not expand but I would guess it to be so small the natural give and take of a fitting would accommodate it.

However if a compression fitting is tightend up solid which is the sort of thing an inexperianced plumber would do, It does cause problems further on in the life of the system.

Why not drain down and take the fitting off and examine it,you can tell if the compression joint has been unduly tightened by the ammount the pipe has been
squeezed under the olive. and have a look at the workings of the valve while you are at it,
If it is a loose thread a couple of wraps of PTFE would probably fix it,

 

[zzag]

Thanks again, Bob. Given that I need to arrange for plumber to come in, drain the system etc I am trying to gather info on as many things to check as possible so that not to have to do it again.

However if a compression fitting is tightend up solid which is the sort of thing an inexperianced plumber would do, It does cause problems further on in the life of the system.

Why not drain down and take the fitting off and examine it,you can tell if the compression joint has been unduly tightened by the ammount the pipe has been squeezed under the olive. and have a look at the workings of the valve while you are at it, If it is a loose thread a couple of wraps of PTFE would probably fix it,

Bob, if I understand you correctly you are suggesting that it is over-tighten olive that might be the source of noise? Or is it the pipe?

thanks!