When is Pressure Reducing Valve Indicating?

8/19/2020

About Pressure Reducing Valves for high pressure water supplies - I understand these need to be "indicating".

How can a PRV be an indicating type? What should I be looking for in inspections?

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2 Comments

Dan Wilder

8/19/2020 09:22:20 am

The Pressure Reducing Valve would only need to be indicating if acts as a floor control valve in addition to being a pressure reducing. The larger valves like the ClaVal 90-21 or the ZW209FP is no different than a check valve and requires a shut off valve on the inlet side (and preferably the discharge side to avoid large drain downs). This is similar to the 2 checks of a backflow device that have the control valves on the inlet and outlet.

The smaller valves like the Zurn ZW4004 show the additional feature of being a control valve and have integrated the indicating portion of it via a sleeve that moves with the handle to show "OPEN" (handle is extended), or not showing open as the valve is closed.

8/26/2020 09:43:02 am

I don't think pressure reducing valve is to be indicative. These are just overpressure protection mechanism for downstream sections of the pumps, lines etc., These are set at predetermined pressure (say 175 psig if using Sch 40/Pipe with design pressure 175 psig) so whenever this demand increase where is potential overpressure is over 175 psig, Pressure Reducing Valve comes (PRV) into picture to protect the system, pops-ups/relieve excess pressure...otherwise in normal situation, stay with no use. The only requirement is to ensure upstream and downstream valve is kept open all the time.

Do we have any references where it's asking it's need to be indicatives? Please advise

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