does anyone have a make or model of a PRV that can go down to 12 PSI? I have one now that goes down to 25 PSI and I'm afraid if I fire the boiler my water pressure will blow the relief. Most PRV go to 25 min...help
This is a hot water, not steam? Most domestic boilers need somewhere around 12-14psi of water pressure in them to operate properly. If it is properly setup to account for expansion when the water is heated, it should not rise much, if at all. The safety valve needs a bit of margin, and since most boilers can handle up to somewhere around 50psi, 30psi safety relief valve gives both the normal pressure range and the overall boiler's safety range in the sweet spot. Changing that valve to 15psi is just asking for problems unless I'm missing something. If you have an autofill valve, once the system is filled properly, shut the supply valve to it off, and the boiler should never get over-pressurized.
Important note - I'm not a pro
Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014
The one I posted is adjustable.
It is just preset at 15 PSI.
But it can be adjusted down if needed.
Watts S1156F or the Taco 339 both are designed for boilers and both are adjustable and come set at 15lbs.
[B]No, plumbing ain't rocket science. Unlike rocket science, plumbing requires a license[B]