[RE-wrenches] SDHW and High Mains Pressure

[Christopher Freitas]

All of the pressure reducers I have seen work at no pressure - I think
you are misreading the specification sheet - the zero drop at zero flow
is referring to pressure drop due to flow - not due to the function of
the regulator - its sort of like zero voltage drop at zero amps...

 

The spec sheet on the Wilkins model 500 does say "The assembly shall be
of the balanced piston design and shall reduce

pressure in both flow and no-flow conditions."  

 

I don't think they would sell many if they didn't reduce the pressure
under no-flow conditions.  

 

 

Christopher

 

 

Christopher Freitas

Director of Research and Development 

OutBack Power Systems, Inc.

cfreitas at outbackpower.com <mailto:cfreitas at outbackpower.com> 

Tel 360 435 6030

Cell 360 202 4239

19009 62nd Ave NE 

Arlington WA 98223 USA

www.outbackpower.com <http://www.outbackpower.com/> 

________________________________

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Peter
Parrish
Sent: Sunday, December 07, 2008 3:22 PM
To: 'RE-wrenches'
Subject: [RE-wrenches] SDHW and High Mains Pressure

 

We are getting ready to install a SDHW system for a customer and we
looked at a number of things regarding his current set up. I just posted
a question about tankless heaters but I wanted this query to be a
separate one. The customer's mains water pressure is 88 psi on a
Saturday afternoon and some time over the next 18 hours, the pressure
went as high as 96 psi. I understand that 80 psi is the high end of the
safe range in general and that 96 psi on a regular basis can/will damage
valves and possibly trigger T&P valves on water heaters.

 

At the recommendation of a plumber I know I looked into pressure
reducers, specifically the Wilkins/Zurn line. All the Wilkins regulators
produce zero pressure drop at zero flow. What good are these products in
protecting plumbing systems from high mains pressures at night when
pressures tend to be the highest and usage is at a minimum or even zero?

 

Are there products that will prevent system pressures from exceeding a
set point (e.g. 60 psi) under any flow condition including zero?   

 

- Peter

Peter T. Parrish, President
California Solar Engineering, Inc.
820 Cynthia Ave., Los Angeles, CA 90065
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885
CA Lic. 854779, NABCEP Cert. 031806-26
peter.parrish at calsolareng.com 


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