On 13-Nov-17 11:48 AM, Oumati Asami wrote:
....

No. That's not what he tried to say. I told him the output pressure
should be constant. He said no. He said the output pressure would be
affected by the input pressure.

To some degree, yes, but for residential regulators of the type the
outlet pressure is much more strongly controlled by the internal flow
pressure drop with flow rate; the pressure drop goes up pretty
drastically with increase flow so the downstream pressure drops. The
point of the regulator isn't so much (actually at all) to keep a
constant downstream pressure as to reduce the maximum pressure to that
which will not be damaging to toilet valves, etc., etc., etc., if used
the distribution pressure that can be quite a bit higher...

He also said the lowest pressure the devise could set to was about 48
psi. I really doubted it. That seems to be quite high for residential
water pressure (not that the pressure is quite high but the lower limit
is quite high). I would think the device could reduce the pressure to 20
psi or lower. But then, I really need to find out the model number and
check the literature.

No, they can be set lower; just how far depends on the spring constant
and design; typically a 50 psi nominal will be able to go to 20 or 30 psi.

A typical data sheet for such a device can be found at
http://www.steamshop.com/ConbracoPDF/36Cseries.pdf

Note on the second page the pressure drop with flow for the typical 50
psi setpoint...

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