How a Water Pressure Reducing Valve Works

Pressure reducing valves, or PRVs, are vital for maintaining safe and consistent water pressure in your home. In this video, we’ll take a detailed look at how PRVs work and why they’re essential for protecting your plumbing system.

Through animations and clear explanations, you’ll learn:

The key parts of a PRV, including the diaphragm, adjusting screw, and valve.
How the gap in the valve reduces pressure, and how it’s similar to a resistor in an electrical circuit.
What happens when water flow stops or when inlet pressure changes suddenly.
How to adjust the outlet pressure using the set screw.
We’ll also explore real-time scenarios, such as what happens during pressure spikes or when faucets are turned off, to show how PRVs react dynamically.

Whether you’re a homeowner, DIY enthusiast, or just curious about plumbing systems, this video will give you a complete understanding of PRVs. Don’t forget to like, comment, and subscribe for more home maintenance and plumbing tips!

0:00 Introduction to Pressure Reducing Valves
0:08 Why Pressure Reducing Valves Are Important
0:23 Overview of a Typical Pressure Reducing Valves
0:30 Identifying the Inlet and Outlet Ports
0:36 The Role of the Diaphragm in a PRV
0:51 Explaining the Adjusting Screw and Spring
1:03 The Valve Stem and Poppet Valve
1:11 How the Valve Operates
1:25 The Gap: Where Pressure Reduction Happens
1:37 Comparing the Gap to a Resistor in an Electrical Circuit
1:46 How Gap Size Affects Outlet Pressure
1:57 Adjusting the Pressure with the Set Screw
2:16 Dynamic Operation of the Valve
2:31 Reacting to Sudden Inlet Pressure Increases
3:02 PRV Reaction to Inlet Pressure Increase (Real-Time Example)
3:44 How the PRV Reacts When Water Flow Stops
4:16 Why the Valve Must Close When There’s No Flow
4:29 What Happens if the Valve Remains Open Without Flow
4:32 Summary of How Pressure Reducing Valves Work
4:36 Protecting Plumbing Systems with a PRV
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Thanks for watching the video How a Water Pressure Reducing Valve Works

[morganinspectionservices]

Thanks for watching!
Remember — a properly working PRV can save your plumbing system from serious damage over time.
If you found this video helpful, give it a thumbs up and check out my other videos on simple ways to protect your home!

[JerimiahBaldwin]

This is certainly the best illustration I have seen for a PRV. Excellent job!

[zimitroperez]

Great video. Super simple and straight to the point, thanks for sharing

[DennisJameson-er]

Excellent demonstration. So clear. Thanks.

[LittleBozo]

Great job. Nice simple basic... the animated illustration was the ticket. New subscriber

[johnlortscher]

Wonderful video. Thank you so much for putting it together and sharing it!😀

[cemilcan]

Perfect video thanks!!! One question;how flowrate corresponds to the pressure drop. What can we say about inlet and outlet flowrates

[ahmedadel]

Thanks alot pro I WAS Searching for hours for this video

[kelvinlord]

Good stuff, thank you.
Best wishes.

[zapatasghost]

Ok. Here's what I needed at 2:03 tightening or loosening to adjust pressure as needed. Tightening the adjustment allow MORE pressure OUT passed the reducer. Loosening it DECREASES the outlet pressure. That's it.

[BeNiceToPeople]

This is awesome. You just saved my butt. Would love to see you put out a video explaining the venturi technology on the new 500XL3.

[thomasmezei]

nice video, I always wondered how they worked. Why couldn't I just choke the pressure back with a simple check valve/tap instead?

[cdrw]

Have a new PRV installed in house, set to 55 psi on outlet. Have water pressure gauge attached to outdoor faucet after the PRV. During the day it measures the expected 55 psi, but in the overnight/morning, it spikes to 80 psi. Is it likely a faulty PRV or is there some other explanation? Thanks!

[VIGHNESH-di]

what if there is no consumption on the outlet. What about the increased pressure in this condition? Where will the excess pressure be released?

[Sparky-wwre]

Excellent demo.

The nature of a pressure reducing valve also has the unintended side affect of acting as a check valve which can be a double edge sword so to speak. While it certainly helps prevent cross contamination of the potable water supply and thus required by some local plumbing codes, it can cause the T&P valve on your water heater to discharge during the heating cycle when no hot water is being drawn resulting in higher energy costs and shorten the life of the water heater. An expansion tank would be required.

[dronesinconstruction]

Thanks, got one installed but wasn’t calibrated

[brettcatterall]

We got roughly 175psi before the regulator. 0.433 psi per foot of water. You can figure out how high the water level is by calculating that which is about 400 ft. Fun fact, submarines know how deep they are by the press of the water.