On 13-Nov-17 11:33 PM, Ed Pawlowski wrote:
On 11/13/2017 11:50 AM, Oumati Asami wrote:


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.Â* Given the entering pressure may vary it can affect
the leaving predsure a bit.Â* If you take constant as being perfect
all the time thenÂ* no.Â* 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.Â* A drop from 50 psi to 42 psi is
functional but a drop from 50 to 5 psi is not.

Â*From 50 to 42 is a drop of 16%. That seems quite large to me. An 8%
drop is acceptable to me but maybe I'm an idealist.

What are you basing your conclusion on?Â* Is it because 8% sounds better
than 16%?Â* I'm basing it on operating a manufacturing plant with air,
steam, city water, recirculated water.Â* We probably had 30 or 40
pressure regulators.Â* I often witnessed drops of 25% with no ill
effects.Â* It was a part of normal operations.Â* Machines and appliances
can take a wide variation unless you are doing some scientific experiments.

If a valve downstream is open, the pressure would drop. When I was with
the engineer, I did open a valve and the pressure dropped from 60 to 42
psi. But this is a totally different thing. It's not my concern. My
concern is: if the input pressure increases, would the output pressure
also increase given that the device is set to a certain pressure below
the input pressure?