Water Heater P&T RV Pressure Setting versus System Design Pressure
Water Heater P&T RV Pressure Setting versus System Design Pressure
(OP)
Having ordered a 60g Elec. Water Heater for an industrial facility to be installed on a domestic water system, now noticed that WH P&T pressure setting is 150 psig whereas my system design pressure per flow diagram is 100 psig. WH vendor is not ready to change the RV to one w/ 100 psig set pressure. To resolve the issue i am thinking to install one RV on piping right downstream the WH w/ 100 psig set pressure. I am wondering do i need another RV w/ the same 100 psig setting upstream the WH and on cold water supply or the one on hot water line is adequate?
Thank you for your input. Next time i am adding an equipment to any system i check its Flow Diagram/sheet carefully!
Thank you for your input. Next time i am adding an equipment to any system i check its Flow Diagram/sheet carefully!





RE: Water Heater P&T RV Pressure Setting versus System Design Pressure
Unless there is some component in the system that cannot be exposed to ~150 psig, the 100 psig RV is not required.
RE: Water Heater P&T RV Pressure Setting versus System Design Pressure
Let your acquaintances be many, but your advisors one in a thousand' ... Book of Ecclesiasticus
RE: Water Heater P&T RV Pressure Setting versus System Design Pressure
Depending on what plumbing code you are working with - typically the maximum pressure allowed at a plumbing fixture is ~80 psig.
These are typically placed upstream of any brach to a water heater
With the PRV placed upstream of the water heater, you would have less than 80 psig and would not need another relief valve.