Pressure Reducing Valve

[Maxspencer]

I have just installed a hot water thermal store and have pressure of 2 bars after the titular valve. When I adjust the blue tap (on left of image) clockwise or anti-clockwise, it makes no difference to the pressure. Do I have to do anything with the Allen key adjusted small black ring on right of valve in order to adjust the pressure or am I in need of a new pressure reducing valve. The thermal store is working a treat on 2 bars and this pressure is within the acceptable range although the installation manual states that 3 bars is ideal so I figured I should aim for that. Any help/suggestions gratefully received.

 

[Elkato531]

The small black ring is just a blanking plug. If you remove it you'll get wet.

 

[Maxspencer]

The small black ring is just a blanking plug. If you remove it you'll get wet.

Thank you. So it sounds like it’s in need of replacement do you think? I think it may be around 15 years old so could be riddled with limescale.

 

[Madrab]

I think someone needs to stop putting PTFE tape around the threads of the fittings, it serves no purpose.

All depends on whether the PRV has a anti tamper lock on it or not. Sometimes just twisting the top will do nothing until the the anti tamper lock is removed, sometimes a screwdriver or an allan key is needed into the top of the valve to engage the valve properly.

 

[TimboTwo]

What is the pressure before the prv?

 

[Maxspencer]

Good point @TimboTwo, I thought about checking this but I was hoping to avoid opening up the plumbing before the prv. It’s really not a problem as the current pressure works well with the new system. As I’d never worked with a prv before, it was just niggling me.

 

[Madrab]

What is the pressure before the prv?

The PRV isn't adjusting the pressure either way according the original post, if it's currently 2 bar then the PRV should be able to at least drop that pressure. Looks like a old reliance PRV and they can typically drop the pressure to 0.5bar.

OP ... if it has a screw slot in the top then that needs to be loosened, if it doesn't then it's a set PRV and will have a disc in the top that details what the pressure is set to. If there is a screw, loosen that, turn the top anticlockwise and then open a tap that it serves to allow the pressure to drop, then turn it back up clockwise to the desired pressure.

As suggested though, your mains may only be 2 bar and it won't go any higher, it should go lower though if it is adjustable. It will probably need a service though if it hasn't been touched in years, strainer cleaned, silicon greased etc.