Any issues having two pressure reducing valves in series?

[Iknowcraig]

Hi all, I am having a new boiler and pre-plumbed unvented cylinder installed soon. The boiler is going to be located around 4M from the stopcock (which is located directly below the 3 bathrooms the system will be feeding). I am also installing a new 32mm water main to ensure good flow.

The pre-plumbed cylinder comes with a pressure reducing valve on it, with a balanced cold feed output. But I am told they cannot spec a 28mm PRV, only 22mm. As I see it if I then feed all outlets from this to ensure a balanced supply I am limiting the effectiveness of the new water main. Also I will then be piping 2x22mm feeds (balanced hot and cold) back to above the main.

What I am thinking is that I could put a 28mm PRV at the main, set to the same pressure as the PRV on the cylinder. Then take a 22mm feed to the cylinder and back for hot water, and take a 22mm cold feed directly from the first PRV to the bathrooms, this will provide the full flow available from my massive (overkill I know) 32mm main. Any issues with this approach?

 

[fezster]

Sounds fine. I did similar - but I did away with the 22mm PRV altogether and replaced with a 28mm Reliance.

 

[Iknowcraig]

Sounds fine. I did similar - but I did away with the 22mm PRV altogether and replaced with a 28mm Reliance.

Thanks, I figured it couldn't do any harm as if the first PRV was supplying say 3.5 bar to the cylinder it just means the 2nd PRV won't have any work to do if it is set the same! plus saves some copper and pipework!