Adjusting the PRV to go to 4 bar..?

[dblvkrb]

any pics of the install?

Of the new mains, stopcock and PRV I assume? No, but I may go and take a look tomorrow and take some pics. I have a picture of the boiler setup (Alpha Flow Smart, 50l) if that would help at all.

 

[Riley]

What is the cold inlet and hot outlet on the boiler

 

[Riley]

Yes boiler pic

 

[dblvkrb]

you sure its not a 20mm main ?

what make of prv are you using

It's a newly installed 25mm main as I mentioned in my original post, I meant 15mm pipe running from the stopcock.

 

[dblvkrb]

You will not increase the flow by increasing the pressure. If that’s what you’re intent on doing you might as well remove the PRV. The PRV could be defective. In terms of what does it reduce to I meant what pipesize is it coming out of the stopcock. Do you notice this reduced flow at all outlets

15mm coming off the stopcock - the flow rate is the same on the 1st floor and in the loft conversion, almost no loss the further up the house you go.

It might be a defective PRV - would this definitely not reduce the flow rate if it were working effectively?

 

[Riley]

Honest opinion I’d be tempted to change the PRV

 

[dblvkrb]

Yes boiler pic

Not the greatest pic, but hopefully gives you an idea of the boiler - the hot flow is only 2 l/m less than off the cold mains, I doubt it is the issue.

 

[dblvkrb]

It's a newly installed 25mm main as I mentioned in my original post, I meant 15mm pipe running from the stopcock.

Also completely forgot make of PRV, will check though.

 

[dblvkrb]

As Riley and others have said pressure and flow are not the same thing. A PRV could have sorted out the splashing tap but will not have affected flow.

As an example:

If we have two taps both with a flow rate of 15 lpm where tap no1 has 6bar pressure and tap no2 has 3 bar pressure, both will fill the sink up in the same amount of time. But when taps are turned on tap no1 will splash much more violently off the surface of the sink due to the much greater pressure than tap no2. i.e. its the same amount of water but coming out with more force, turn the pressure down and water hits the sink with less force so doesn't splash/bounce but its exact same amount of water per minute hitting the sink.

I understand this, and I'll caveat by saying I didn't personally test the flow rate before the PRV installation but it's obvious it has reduced both the flow rate and the pressure. I'm guessing where we may be getting to is possibly a defective/clogged PRV?

 

[Aire]

As much as i appreciate why everyone is saying increasing the pressure of the prv won't do anything, turning it up and seeing if it improves isn't going to hurt, even by half a bar, the boiler is rated up to 5bar anyway so it's not going to hurt. And if it doesn't work atleast you've ruled it out.

 

[rpm]

Seen 6bar static pressure reduce to 0.6bar dynamic pressure along with the sort of flow you would expect from 0.6bar.

 

[rpm]

Not the greatest pic, but hopefully gives you an idea of the boiler - the hot flow is only 2 l/m less than off the cold mains, I doubt it is the issue.

View attachment 36032

Not the greatest pic, but hopefully gives you an idea of the boiler - the hot flow is only 2 l/m less than off the cold mains, I doubt it is the issue.

View attachment 36032

Not the greatest pic, but hopefully gives you an idea of the boiler - the hot flow is only 2 l/m less than off the cold mains, I doubt it is the issue.

View attachment 36032

Those valves supposed to be closed guys?

 

[dblvkrb]

Those valves supposed to be closed guys?

So.. I could test increasing the static (PRV) pressure to see if the dynamic pressure improves the flow, have I understood this right?

I'll pass on whether the valves should be closed (I did not install the boiler) - but it is working as expected and the hot flow is similar to the cold mains flow.

 

[Aire]

Yes you can increase the pressure, as I said your boiler is rated at 5 bar, stick below that and you'll be fine.

And no those valves aren't supposed to be closed, but then the hot feed coming from the top of the heat store should also feed the boiler through a blending valve mixed with the cold main. Whoever installed the boiler hasn't finished it.

 

[Riley]

If that’s a heat store then what pressure is that safe up to??