The red needle is just a marker, used to indicate where to adjust the pressure to.
Moved house a few months ago and had a problem with a broken toilet flush valve. Whilst isolating the water, I noticed I have a pressure reducing valve. My static water pressure on the gauge is showing nearly 5.4 bar (78psi)...which seems quite high from what I read. When water flows from a tap, the pressure drops to about 2 bar (so the gauge appears to be working). I tried turning the nut on the top of the valve a couple of turns to the minus and it makes no difference to the gauge reading. The red needle doesn't move at all - what is this for?
I'm tempted to call a plumber to deal with a slightly leaky stopcock anyway. Should I be getting him to look at this too, or should I just leave it?
The red needle is just a marker, used to indicate where to adjust the pressure to.
Don't just do something, sit there. - TNH
Ah, thanks, I see...wasn't sure whether it was this or a high/low indicator.
Think I might just bite the bullet and get a plumber in and get him to do a few plumbing jobs whilst I am at it. If this valve is faulty and doesn't actually regulate properly, I'm assuming changing it is a straightforward job for a professional.
Hi
did you turn the large plastic hex shaped body of the valve or the small screw on the top?
There's usually a small screw on the top which is used to adjust the pressure out of the valve. Sometimes it's hidden under a sticker or a small cap and could be a screw or an allen head bolt.
The larger hex shaped body of the valve can be undone and the valve cartridge and strainer withdrawn to clean etc. (turn water off first).
The red needle is like a tell tale which you set by turning the plastic centre that sticks out of the gauge with a screwdriver. When you turn the small screw/nut to adjust the valve then the black needle will show the valve outlet pressure and should change as you turn the screw in either direction.
No, I turned the screw at the top - probably a couple of turns left which made no effect on the needle whatsoever, then back. The needle does move though - when I run a tap it drops to about 2 bar, when all taps are closed, the static pressure is as you see it - about 5.3bar.
If you can't adjust the valve then it could well be that it needs servicing/changing. It looks like you have a limescale reducer fitted so there may be some debris/scale in the valve body preventing it from operating properly. (Are you in a hard water area?)
You may need to give the adjusting screw a good few turns to see any change as it looks to be fully open if it's reading 5+ Bar. (Usually these are pre-set at 3 Bar).
Yes, Greater London so quite a hard water area. Thanks for the advice - much appreciated.
No worries. If it does need changing then its a simple swap (assuming the stopcock is working properly) Valve is about £30.
Edit to add that Rob s has just mentioned same thing re ease of swap while I typed and dawdled whilst making this post :)
Also the scale reducer (Aquabion in your install) should be changed periodically according to the manufacturers. There may be a date on the valve or sticker to indicate so might be worth looking at this too. These can be pricey though although there are some cheaper alternatives to the Aquabion type (Calmag etc).
There's a fair amount of debate as to how effective or otherwise these scale reducers are with the usual snake-oilery caveats :)
Last edited by jeff; 7th April 2021 at 12:06.
Surely turning the adjuster screw will only show a difference when a tap is open - it won't change the static pressure reading of 5.4bar. If you open a tap & see the gauge reading 2bar & then adjust it you should see the reading change.
Have you tried this & seen no change?