How to Diagnose & Repair Building Water Pressure Regulators & Water Pressure Reducing Valves

Water Pressure Regulator Piping & Installation

Why did the plumber install a larger-diameter pressure reducing valve on my system? And I'm getting pressure spikes!

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 2018-12-19 by Ted

by (mod) -

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.

Water Pressure vs Water Hammer Noise

Can I use the pressure regulator to stop water hammer?

The potable water hammering in upstairs bathroom. Water hammering does happen for Any other cold water lines . On 2018-05-07 by Nicholas Gallina

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.

While it's water velocity that causes water hammer when a valve is closed, water pressure is one of the important factors in water velocity.

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.

Handling Water Pressure Spikes at the Pressure Regulator

Both old and replacement water pressure regulators won't handle pressure spikes

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 2016-11-08 by Jay

Solution by (mod) - 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.

Water Pressure Regulator Output is Too Low

Why can't I adjust my water pressure regulator to get higher water pressure in the house?

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

Explanation and advice 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

See WATER PRESSURE BOOSTER PUMPS  to read details.

Using a Water Pressure Regulator Bypass

Temporarily use a pressure regulator bypass?

How do you make a pressure reducer let water thru till you can replace it - (June 8, 2014) Karen

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

The installation of water diverters and bypass valves may be regulated by plumbing codes where you live.

For example see this example at UpCodes [website] for P2911.8.1 Bypass Valve excerpt from the Texas Plumbing Code.

Check Valves Prevent Backflow at Water Pressure Regulator

Can water from the house flow backwards through the pressure regulator or a bypass and flow back out to the street?

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 2016-07-08 by Tom Paradsie

Answer by (mod) - occurrence of backflow through water pressure valves is possible: use a check valve

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.

See CHECK VALVES, WATER SUPPLY, DRAINS, PUMPS 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.

Water Pressure Regulator Leak Repair

Is it possible to repair a leaky water pressure regulator?

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? (June 13, 2014) Anonymous

Reply:

Most likely, yes.

In any case, if your pressure regulator is leaking you need it either repaired or replaced - don't tolerate a leak into your building wall, ceiling or floor cavity or your risk costly water damage and mold contamination.

A leak around the water pressure regulator adjustment stem is most likely a failed washer or O-ring. A complete water pressure regulator repair kit costs between $25. and $75 U.S. for a residential type water pressure regulator and the kit will contain probably more parts than you need: O-rings, springs, and diaphraghm.

But be sure the kit is matched to your specific water pressure regulator.

I have also on occasion simply taken a bad O-ring out of the pressure regulator and stopped by my local hardware store or automotive supplier to match the O-ring alone - for a cost under $5.00.

Water Pressure Regulator Failure: Pressure Drops

Our well water pressure drops after the pump turns off but the foot valve isn't leaking

Pump goes up to pressure then the pump shuts off and water goes back towards the well, but foot valve is holding pressure (Sept 18, 2014) Victoria

Reply: list of common causes

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.

Or there's a toilet running that you haven't noticed, or some other building water supply leak.

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

at WELL WATER PRESSURE DIAGNOSIS

Water Pressure Regulator Failure: Pressure Creeps Up

What do we do to the pressure regulator if our water pressure regulator keeps rising?

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

Reply:

Anon: I suspect that your pressure regulator is damaged, perhaps with a leaky diaphraghm.

I'd repair or replace it.

Water Pressure Too High

Our water pressure regulator won't go below 80 psi

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? (June 11, 2016) lcotten

Reply: your water pressure regulator isn't working and should be replaced.

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.

Watch out: be sure to read both our safety warnings and our repair advice

at WATER PRESSURE TOO HIGH: DANGERS

Followup by Cotten

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

Reply by mod

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).

Followup by Cotten

OK - thanks. That helps me understand what could be occurring. I'll look into that. Appreciate the response very much.

Water Pressure Setting Reading & Accuracy

How do I read the water pressure regulator dial

How do you read water pressure regulator that has a dial with numbers on it? 2016/07/04 kansas city

Reply: pressure gauge attached to water pressure regualtor

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.

See details at WATER PRESSURE MEASUREMENT