PRV Correct setting and cons advice

[BobbyJoe]

Hi everyone,

Just wanted some confirmation regarding a PRV fitted to the mains supply in my building. All 6 flats in the building are now connected to the mains water feed supply and the water tanks in the attic have been disconnected (each flat has a combi gas boiler).

My question is the PRV's on the pipes are set at 1.5 bar is that correct they shouldn't be any lower or higher?

What are the benefits of having PRV'S fitted and if they fall below 1.5 bar then what would happen to the water pressure in the flat would it be weaker? Also what would happen if the PRV was set too high what would happen to the water in the flat then?

Thank you for reading and I would be grateful for your advice

 

[John.g]

Is it just one PRV on the mains or separate PRVs to each flat and how high is the highest flat?.

 

[ShaunCorbs]

Evens the pressure out for all the tenants can I ask is there a problem?

 

[BobbyJoe]

Thanks for the reply, from what I can see there are 4 PRVS in total connected to the pipes (could be 6 in total but I just saw 2 prvs on 2 separate pipes on my side of the attic and two on the other side of the attic, I am on the top floor and there are two flats below me.
I would say my flat is around 10 metres high from the ground up. I was the only person in the building connected to the mains water feed for all my water, and recently everyone else got connected. The water pressure is still the same which is good pressure but now I notice when I run my basin mixer tap, the water and temperature fluctuate if my neighbour is using there bathroom tap is this normal?
Also there is no chance of back flow or water mixing since we are now all connected to the mains feed?
Thank you once again

 

[ShaunCorbs]

Yes normal

 

[BobbyJoe]

1.5 bar for all flats pressure is normal?

 

[ShaunCorbs]

Yes you shouldn’t need much more as it’s a flat

 

[BobbyJoe]

If the pressure is too high or too low what happens to the water then?

 

[ShaunCorbs]

You mean if the prv fails

If to low you will notice you can pee faster if to high you could get water hammer or depending on your water pressure pre you could pop joints

 

[BobbyJoe]

Thank you I understand better now. If we are all now using mains water can cross contamination or bacteria occur, for example can the water in my flat mix with my neighbours through the pipes or vice versa? How would I know if water was being mixed?

PRV's and isolation valves are on the water pipes in the attic

 

[ShaunCorbs]

No it can’t as there’s a non return valve in the prv

 

[John.g]

Thanks for the reply, from what I can see there are 4 PRVS in total connected to the pipes (could be 6 in total but I just saw 2 prvs on 2 separate pipes on my side of the attic and two on the other side of the attic, I am on the top floor and there are two flats below me.
I would say my flat is around 10 metres high from the ground up. I was the only person in the building connected to the mains water feed for all my water, and recently everyone else got connected. The water pressure is still the same which is good pressure but now I notice when I run my basin mixer tap, the water and temperature fluctuate if my neighbour is using there bathroom tap is this normal?
Also there is no chance of back flow or water mixing since we are now all connected to the mains feed?
Thank you once again

If you have a water meter then you will/should have a non return valve, what is the make/model of the PRV?.

 

[BobbyJoe]

Hi,

I think I got how many PRV's are in the attic wrong. The building has 6 flats in total each floor has 2 flats and my flat is the top floor about 10 to 11 meters approx from the ground.
Each side of the attic has one mains water feed pipe one for my side of the building and the other side for my opposite neighbours side and one PRV on my side for 3 flats in total.
I would like to know if it is normal to have 1 PRV fitted for 3 flats and what bar should it be set at? The factor said it is set at 1.5 bar but since I am at the top floor should it not be higher?
Is each flat not supposed to have a PRV each and would it make a difference if everyone else has a PRV installed on the pipework except me?
I would appreciate advice on how many prv's should be installed because the flow and pressure of my bathroom water was much better before the PRV was installed, I didn't have to turn the mixer tap fully either to get hot water and had no fluctuations in water either.

 

[John.g]

There really be one PRV for each flat but if the mains pressure cant supply at least 1.5bar pressure when everyone is using water then the pressure will fall below 1.5bar even with your own PRV, one PRV for a number of flats probably makes it worse, is there a pressure gauge fitted to this PRV?, at least if there is you can look at it during times of high demand.

 

[BobbyJoe]

Hi everyone,

I am going to get the plumbing company to adjust the PRV as 1.5 bar is too low for a top floor flat which is approx. 11 to 12 metres high from the ground up as the pipework is in the attic space.

Any recommendations on what bar the PRV should be set at because with the cold tap fully open I can fill a 10 litre bucket with cold water in 25 seconds. The factor said 1.5 bar was the usual but he also admitted this is the first time they were disconnecting water tanks in the attics of flats built circa 1960s and connecting water in bathrooms to be fully mains water fed and they were having teething problems.

Any advice would be great as I will get in contact with them asap and suggest the bar as there were no issues with pressure, flow or fluctuations of the water in my bathroom before all this drama., thanks again.

 

[John.g]

24LPM, even into a bucket isn't bad!!.
If you are getting 1.5M at your flat elevation then it doesn't matter whether your 3M up or 12M (from that point of view), even if the PRV is set to 5bar but the pressure available is still only 1.5 bar or less you won't get any more pressure/flow.

What or who is a "Factor"