On 11/13/2017 11:25 AM, Oumati Asami wrote:
On 12-Nov-17 8:34 PM, Retired wrote:
On 11/12/17 7:40 AM, Oumati Asami wrote:
On my water pipe system, there is this bell shape thing with a bolt
on the top. I always thought it a water pressure regulator.

The other day, the engineer of my community came to check my water
system. He said that thing is not a water pressure regulator but a
water pressure reducer. According to him, a water pressure regulator
is a device that would keep output water pressure constant. If the
outgoing water pressure is set to, say, 50, no matter what the main
pressure is, be it 100, 90, 80, or 70 psi, the output is always 50 psi.

A water pressure reducer, according to him, is a device whose output
pressure is affected by the input pressure. If the main pressure is,
say, 80 psi, and the output pressure is set to 50 psi, when the main
pressure is increased to 100 psi, the output pressure would also
increase.

Does he make sense?

No, according to this maker's article, he has it backwards.

"Even if the supply water pressure fluctuates, the *pressure reducing
valve* ensures a constant flow of water at a functional pressure, as
long as the supply pressure does not drop below the valve's pre-set
pressure."

http://www.watts.com/pages/learnAbou...=64#whatiswprv


I read the article. The article says "ensures a constant flow of water
at a functional pressure". I don't know what a "FUNCTIONAL PRESSURE"
means. Is it "constant pressure" or not? That's what I want to know.

Define constant. Given the entering pressure may vary it can affect the
leaving predsure a bit. If you take constant as being perfect all the
time then no. If you take constant as being withing a normal tolerance
of a few psi in either direction, then yes. Functional pressure means
the variation is minimal and your toilet flush or dishwasher will still
work. A drop from 50 psi to 42 psi is functional but a drop from 50 to
5 psi is not.