Noisy lock shield valve (video)

bhm1712 · 7 Feb 2017

Any ideas why my systems first radiator LSV creates this noise when it's opened between 1/8 & 1/2 of a turn? I need to have it turned down this low to prevent it taking all the flow from the rest of the system but it starts making this noise. More than half a turn open and it stops.

Madrab · 7 Feb 2017

Oldish valve/rad? Water causes the noise as it passes through the restricted valve into the narrow rad, you should feel it if you hold the valve.

bhm1712 · 8 Feb 2017

It's a about 20 years old that radiator but the valve is only a few years old.

So I take it this is something we have to live with until we change the rad?

Madrab · 8 Feb 2017

I'd say it's more likely to be a noisy valve, rather than the rad itself if it stops when the valve's opened up more.

D_Hailsham · 8 Feb 2017

Madrab said:
Water causes the noise as it passes through the restricted valve into the narrow rad, you should feel it if you hold the valve.

Lockshield valves are normally on the return so the flow would be in the other direction, i.e from the rad into the valve.

The pump could be on too high a speed so the flow is too fast. LS valves would then have to be closed down more to give the correct differential.

Madrab · 8 Feb 2017

D_Hailsham said:
Lockshield valves are normally on the return so the flow would be in the other direction, i.e from the rad into the valve.

Of course, If that's the way's it's been configured, or if that valve's replaced a TRV or the rad's being used as a bypass then both would be lockshields/turn valves, so it could be either or.

OP, is this a new problem or has it been like that for a while?

bhm1712 · 8 Feb 2017

It's always been like it since I balanced the system (previously the LSV was practically fully open and so a lot of flow going through the first radiator on the system)

The LSV is on the flow pipe on this radiator as the TRV had been fitted to the return before our ownership of the house.

This particular setting of about 1/8 ish open gives me a 12 degree differential across the radiator. Other than this noise at this rad, everything else working fine.

bhm1712 · 8 Feb 2017

The TRV's are Drayton RT313 so multi directional.

Steelmasons · 8 Feb 2017

Has the rad been bled?..sounds like air in the rad...open vented system or sealed?

bhm1712 · 8 Feb 2017

Sealed system , all bled. Fernox inhibitor inside. A recent drain down revealed water practically as clean as tap water coming out and a very clean magnetic filter.

Terrywookfit · 8 Feb 2017

D_Hailsham said:
Lockshield valves are normally on the return so the flow would be in the other direction, i.e from the rad into the valve.

The pump could be on too high a speed so the flow is too fast. LS valves would then have to be closed down more to give the correct differential.

There is no physical difference between lockshield and Wheel head valves apart from the head.!!

Madrab · 8 Feb 2017

If it doesn't do it when the valve is fully open then it seems that it has to be turbulence, especially if there's no air in the system. Some valves have very small drillings and if they are older washer type valves then it could be getting sticky only being slightly open as the hot water passes through it. Does it get quieter once it all heats up?

bhm1712 · 8 Feb 2017

Yes it does indeed. By the time the system has been fully heated through and up to temp it quietens right down.

Madrab · 8 Feb 2017

Sounds like it could be the valve, basically it's a very narrow channel/space when the valve is just open a whisker and the hot water is pushing it's way past the jumper up into the cooler rad, once it warms up it calms when the flow settles down.

Steelmasons · 8 Feb 2017

bhm1712 said:
Sealed system , all bled. Fernox inhibitor inside. A recent drain down revealed water practically as clean as tap water coming out and a very clean magnetic filter.

System pressure??.location of circulator?..radiator in question @ highest point of system??

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Noisy lock shield valve (video)

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