Since the time I moved into my house, I've had problems with water hammer. More recently, I've had some faucets start to leak. I also noticed that after showers/baths, the hot water would surge when the sink faucet was turned on.
After installing water hammer arrestors, and securing all the plumbing. I have reduced, but not eliminated the hammer. As for the surging water after a large hot water demand. I recognized that, as a symptom of a failed expansion tank.
In the process of replacing the tank, I took a water pressure reading in order to charge the tank. When I got a reading of 85 psi, I was slightly concerned. Especially when the instructions for the expansion tank, said not to charge the tank over 80 psi. Of course I went directly to the code books, and discovered that codes call for a PRV for pressures over 80 psi.
International Residential Code 2012
Chapter 29 Water Supply and Distribution
Section P2903 Water-Supply System
P2903.3.1 Maximum pressure.
The static water pressure shall be not greater than 80 psi (551 kPa). When main pressure exceeds 80 psi (551 kPa), an approved pressure-reducing valve conforming to ASSE 1003 or CSA B356 shall be installed on the domestic water branch main or riser at the connection to the water-service pipe.
International Plumbing Code 2012
Chapter 6 Water Supply and Distribution
Section 604 Design of Building Water Distribution System
604.8 Water pressure reducing valve or regulator.
Where water pressure within a building exceeds 80 psi (552 kPa) static, an approved water-pressure reducing valve conforming to ASSE 1003 or CSA B356 with strainer shall be installed to reduce the pressure in the building water distribution piping to not greater than 80 psi (552 kPa) static.
To make a long story short, I'm installing a pressure reducing valve (PRV). However, I'm not sure where I should set it. I've gotten used to the high pressure, and I'm afraid lowering it will be disappointing. At the same time, eliminating water hammer, and not worrying about damaging fixtures would be a good thing.
I've searched the internet, and found recommendations anywhere from 40 to 80 psi. Family Handyman says that "... 45 to 55 psi is ideal.". I've also found that most PRVs come preset to 50-55 psi. Other sources say that anything over 60 psi, may cause damage to the plumbing system. IRC requires pressure to be above 40 psi, so I know I want to be above that.
P2903.3 Minimum pressure.
The static water pressure (as determined by the local water authority) at the building entrance for either public or private water service shall be not less than 40 psi (276 kPa).
What pressure should I set the pressure reducing valve to?