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Water pressure regulator (C) Carson Dunlop Associates How to Diagnose & Repair Building Water Pressure Regulators & Water Pressure Reducing Valves

Water pressure regulator controls:

This article describes how to diagnose & repair a bad water pressure reducing valve or water pressure regulator that can result in either building water pressure and flow that are too weak, or building water pressure that is dangerously high. Distinguishing between static water pressure, dynamic water pressure, and water flow rate can help diagnose water problems in a building.

Here we explain these concepts and we describe how to measure water pressure and flow at a property where either municipal water supply or a private well and pump water supply is in use. Our sketch at page top, courtesy of Carson Dunlop Associates, shows the key components found where municipal water supply enters a building.

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What is a Water Pressure Regulator or Pressure Reducing Valve, Where are They Installed, Why?

Watts Series 23B 123LP N250 N250B Water Pressure Reducing Valve details (C) InspectApedia.com adapted from Watts(R) cited in detail in this article

These questions & answers about water pressure reducing valves & regulators were posted originally at WATER PRESSURE REDUCER / REGULATOR - be sure to review that information.

[Click to enlarge any image]

On 2018-12-19 by (mod) - why did the plumber install a larger-diameter pressure reducing valve on my system?

Ted I'm not aware of any benefit of installing a size-larger pressure regulator on the water line - often it's a matter of what the plumber had at hand when the work was needed in the first place.

A 3/4" regulator on a 3/4" water supply line should be fine.

Watch out: if you are seeing high overpressure as high as 130 psi there is risk of burst pipes, building flooding, and even personal injury.

At WATER PRESSURE REGULATOR ADJUSTMENT where we provide links to PDF files of Watts water pressure reducing valvefs you'll see that the company does provide a line of high-capacity water pressure reducers for high-pressure incoming water systems or where higher flows are needed.

On 2018-12-19 by Ted

I have a Watts 600xl "1in" pressure regulator on a "3/4 in" line.

Why was a larger diameter regulator installed on a smaller line? Is there advantage to this set up for reducing the incoming water pressure (150 psi)? I am experiencing water pressure spikes up to 130 psi and need buy a new one but a different model which will require cutting the 3/4 in copper pipe. Does it matter whether I get the 1in pressure regulator or the 3/4in size? Thank you.

On 2018-05-07 by (mod) - fix water hammer by adjusting water pressure and flow

Nicholas

It's common for water hammer to occur when just a specific fixture is in use. The nuances can be just that - subtle, involving a combination of water pressure, pipe lengths, routing, elbows, flow rate, fixture properties, altitude, even temperature.

Details on diagnosing and fixing the water hammering sound are

at WATER HAMMER NOISE DIAGNOSE & CURE

Often I can "fix" a water hammer banging water pipes problem fixture by slightly closing its individual water supply valve.

Sometimes even changing a faucet strainer will do the trick.

On 2018-05-07 by Nicholas Gallina

The potable water hammering in upstairs bathroom. Water hammering does happen for Any other cold water lines .

On 2016-11-08 by (mod) - t the problem may not be the pressure regulator itself

Jay,

One thing we can infer is that the problem may not be the pressure regulator itself but some other condition. Perhaps the supply pressure exceeds the valve's capacity.

In some high pressure delivery systems we have to install a pair of PRVs in sequence.

On 2016-11-08 by Jay

I have a job where I installed a new direct prv because old one wouldn't hold the set pressure it would still spike. But now new one does same thing wondering what's going on

On 2016-09-07 by (mod) -

Paul, Measure the incoming water supply pressure; If that is below 39 the pressure regulator is not going to ever get it above 39. In that case, if you want more water pressure (flow rate) you'll want to install a booster pump; search InspectApedia.com for

WATER PRESSURE BOOSTER PUMP to read details.

On 2016-09-0 by Paul psteffan13@gmail.com

I replaced my watts regulator and adjusted the screw" . can't get pressure over 39 psi. Too low. 20 yr old house. Copper pipes in good shape. What am I missing?

On 2016-07-10 by (mod) - backflow through water pressure valves

Tom:

Great question. While pressure reducing valves are expected to be "one-way", water can indeed flow "backwards" from the downstream side of the system if that pressure exceeds the incoming pressure on the inlet side of the valve. The risk of that happening depends on several factors such as the valve design and the presence of a separate backflow preventer that is required in many building jurisdictions.

Backflow can occur quite easily if the municipal supply water pressure should drop for any reason. Backflow preventers are often installed - at the incoming water line near the main shutoff valve as well as at pressurized containers or systems such as at a hot water heating boiler.

Search InspectApedia.com for BACKFLOW PREVENTER VALVE to read details.

Some water pressure reducers include a special check valve that addresses pressure increases in the system due to water heaters or other conditions.

On 2016-07-08 by Tom Paradsie

Does a pressure reducing valve "with a by-pass" allow water to flow from the downstream side of the prv back to the source when the downstream pressure exceeds the setting of the prv? If not is there some type of valve that does this?

On 2016-07-04 by (mod) -

Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies

Question: testing water pressure regulators

(Sept 2, 2011) billc said:

it would be very helpful to include a section on testing the pressure regulator.

the regulator on my system seems to allow the water pressure to creep upwards. the pressure is regulated to a lower value after the water is run for a second and then shut off, but i can watch the pressure slowly creep upwards. overnight it is a good 20psi over the set pressure.

Reply:

Thanks for the suggestion, Bill C.

Under WATER PRESSURE REDUCER / REGULATOR near the top of this page you'll see a new link we've added, titled

Water Pressure Regulator Test, Repair

We would much appreciate hearing any comments, critique, suggestions, or further questions that you may have after you've taken a look at that article. We are dedicated to making our information as accurate, complete, useful, and unbiased as possible: we very much welcome critique, questions, or content suggestions for our web articles. Working together and exchanging information makes us better informed than any individual can be working alone.

Question: high city water pressure

(Aug 15, 2012) Robert said:

City water pressure is very high. I have a spare pressure tank. I am thinking of routing city water supply through it and use a pressure regulator to maintain 50 psi level. is this possible? please teach me how? Grateful for your kind thoughts.

Question: hot to set water heater tank control

(Feb 16, 2014) Anonymous said:

I need help. I have a water heater tank and would like to set or control at certain degree. Some people say to put anti scald device. I am having difficulty to find anti scald device with meter or programmable. Any body can help me, i appreciate.

Reply:

Anon:

I'm unclear what you meant or need by "programmable" anti scald device. Anti-scald devices do have a temperature adjustment and are set to avoid dangerous scalding burns by mixing cold in with outgoing hot water - either right at the water heater or at the point of use such as a bath tub or shower or sink.

Search InspectApedia for

Anti Scald

And you'll see several articles describing these devices, what they look like, who makes them, and where & how they are set and installed.

Question: lost water pressure after TP valve replaced

(Mar 18, 2014) concerned mate said:

I recently moved into my gfs house and a few weeks ago the pressure relief valve was fixed and now theres little too no water pressure its a well water system and nothings clogged or backed up thanks

Reply:

Concerned,

If a pressure relief valve was fixed that would have nothing to do with changes in building water pressure itself. If you meant that the water pressure regulator was changed or "fixed" the problem may lie there.

Question: pressure regulator bypass

(June 8, 2014) Karen said:

How do you make a pressure reducer let water thru till you can replace it

Reply:

If a bypass loop is installed around the pressure regulator you'd open that control valve - but

Watch out: high water pressure without the regulator working may cause leaks or even unsafe conditions

Question: leaky water pressure regulator

(June 13, 2014) Anonymous said:

Water is slowly dripping out of the adjustment stem on my valve, Replacing the valve requires some wall removal. Will a repair kit fix this problem?

Reply:

Most likely, yes.

Question: well pump pressure questions

(Sept 18, 2014) Victoria said:

Pump goes up to pressure then the pump shuts off and water goes back towards the well, but foot valve is holding pressure

Reply:

Victoria

I'm not sure how you know the foot valve is OK, but if it were and water were still flowing back into the well then there is perhaps a leak in the well piping.

For details about diagnosing poor well water pressure and flow, start

at WELL WATER PRESSURE DIAGNOSIS

Question:

(Sept 17, 2014) Victoria said:
Pump goes up to pressure then the pump shuts off and water goes back towards the well, but foot valve is holding pressure

Reply:

Victoria

I'm not sure how you know the foot valve is OK, but if it were and water were still flowing back into the well then there is perhaps a leak in the well piping.

Question:

(Feb 6, 2015) Anonymous said:
HOW TO ADJUST THE VALVE PRESSURE

Reply:


IN the Article Indexc found at CONTINUE READING links just above you can read details about how to adjust the water pressure regulator in the article titled

WATER PRESSURE REGULATOR ADJUSTMENT

Question: water pressure regulator keeps rising

(Apr 16, 2016) Anonymous said:
My water pressure regulator keeps rising though I have it set low. What do i do?

Reply:

Anon: I suspect that your pressure regulator is damaged, perhaps with a leaky diaphraghm. I'd repair or replace it.

Question: water pressure doesn't fall below 80 psi

(June 11, 2016) lcotten said:
When I test water pressure in my house, I get 80 psi pretty consistently (with all taps closed). I have tried "turning down" the pressure on my water pressure regulator, such that it is reduced to a little more than a trickle out my taps. And yet with all taps closed, I still read 80 psi on my system. Is it possible that flow can be reduced with out reducing pressure (does not seem possible to me)? Or could pressure on my system be coming from another source some way? Any ideas?

Reply:

If you adjusted the output pressure of your whole-house water pressure regulator and didn't actually see a change in its output pressure then the regulator is not working.

Question:

(June 11, 2016) lcotten said:
Even though the flow is reduced to a trickle after adjusting down the output pressure almost as low as it can go?

Reply:

A pressure regulator regulates PRESSURE. If you set the pressure regulator down as low as it will go and the house water PRESSURE does not change the device is not working properly. You may be restricting an orifice and thus limiting the flow rate (think gallons per minute) but if the pressure doesn't change you're not regulating pressure (pressure is best read with a pressure gauge when no water is running).

(June 11, 2016) lcotten said:
OK - thanks. That helps me understand what could be occurring. I'll look into that. Appreciate the response very much.

Question: how to read the water pressure regulator dial

2016/07/04 kansas city said:

How do you read water pressure regulator that has a dial with numbers on it

Reply:

Kansas - presuming you are asking about a water pressure regulator that has an attacahed pressure gauge:

When no water is running, IF the gauge is accurate and un-damaged, and

IF the gauge is on the OUTLET side of the water pressure regulator,

THEN it will tell you the static water delivery system pressure in some measurement such as PSI - depending on where you live and the scale used on the gauge.

Most gauges will tell you their pressure reading units. Quoting a simple Google search, "The standard SI unit for pressure measurement is the Pascal (Pa) which is equivalent to one Newton per square meter (N/m2) or the KiloPascal (kPa) where 1 kPa = 1000 Pa. In the English system, pressure is usually expressed in pounds per square inch (psi)."

When water is running in the building the gauge pressure is misleading and in accurate.


...

Continue reading  at WATER PRESSURE REDUCER / REGULATOR - topic home, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Water Pressure Diagnosis and Repair Articles

Suggested citation for this web page

WATER PRESSURE REDUCER / REGULATOR FAQs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to WATER SUPPLY, PUMPS TANKS WELLS

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