water pressure reducing valve and water pressure regulator

On my water pipe system, there is this bell shape thing with a bolt on the top. I always thought it a water pressure regulator.

The other day, the engineer of my community came to check my water system. He said that thing is not a water pressure regulator but a water pressure reducer. According to him, a water pressure regulator is a device that would keep output water pressure constant. If the outgoing water pressure is set to, say, 50, no matter what the main pressure is, be it 100, 90, 80, or 70 psi, the output is always 50 psi.

A water pressure reducer, according to him, is a device whose output pressure is affected by the input pressure. If the main pressure is, say, 80 psi, and the output pressure is set to 50 psi, when the main pressure is increased to 100 psi, the output pressure would also increase.

Does he make sense?

Reply to
Oumati Asami
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Reply to
Jack Legg Engineering LLC

No, according to this maker's article, he has it backwards.

"Even if the supply water pressure fluctuates, the *pressure reducing valve* ensures a constant flow of water at a functional pressure, as long as the supply pressure does not drop below the valve's pre-set pressure."

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Reply to
Retired

No, I've never seen a "pressure reducer", only pressure regulators. Also, the concept of a pressure reducer is pretty stupid. You want a regulator that is capable of taking an unregulated incoming pressure and then maintaining the set constant pressure on the other side, as long as the desired set pressure is at the incoming pressure or lower. I suspect that's what you have and your thinking on this is correct.

Reply to
trader_4

replying to Oumati Asami, Iggy wrote: The Engineer's right in his description , but wrong with your device. Plain and simple, if you have a Bell or Cone on top you have a Regulator or Limiting Valve. Under the Bell or Cone is a Spring that fixes your flow-rate, opening or closing automatically in response to water pressure fluctuations. This and yours delivers a fairly constant outlet pressure.

While the word Reducer is correct for yours, because it's actually doing that and the name is even interchangeable by some people. However, the proper usage of the word Reducer usually applies to devices that don't have a spring and are just designed with a static fixed flow-rate or low-flow. These rely on supply pressures being mostly constant, therefore they do fluctuate whenever the supply does.

Reply to
Iggy

No, he's not right in his description. What the poster said was that the "engineer" said that it works by maintaining a constant, fixed, reduction amount in output pressure versus input pressure. No matter if you call it a regulator or a pressure reducing valve, I've never seen one work that way. They all work by maintaining a constant, set output pressure that's adjustable.

A reducer that just takes a fixed X PSI off the incoming pressure and then varies the output up and down as the unregulated side varies would be pretty worthless. He can verify what he has, just get the make and go to the manufacturer's website.

Reply to
trader_4

I read the article. The article says "ensures a constant flow of water at a functional pressure". I don't know what a "FUNCTIONAL PRESSURE" means. Is it "constant pressure" or not? That's what I want to know.

Reply to
Oumati Asami

Define constant. Given the entering pressure may vary it can affect the leaving predsure a bit. If you take constant as being perfect all the time then no. If you take constant as being withing a normal tolerance of a few psi in either direction, then yes. Functional pressure means the variation is minimal and your toilet flush or dishwasher will still work. A drop from 50 psi to 42 psi is functional but a drop from 50 to

5 psi is not.
Reply to
Ed Pawlowski

There is a bolt, much bigger than the bolt on the top, on the bottom of the device. I unscrewed and removed it. A spring, around 2" long and maybe 1/2" in diameter, fell off the device. Is that normal? I thought there was a diaphragm or something underneath the spring that would prevent the spring from falling off.

Reply to
Oumati Asami

I found the make but still need to find out the model number.

I'm not sure the engineer meant a reducer would reduce the water pressure by a fixed amount. The output pressure would increase when the input pressure increases but not by the same amount. Let's say the input pressure is 80 psi and output pressure is set to 50 psi. When the input pressure is increased to 100 psi (an increase of 20 psi), the output pressure would be higher than 50 psi but probably not 70 psi.

Reply to
Oumati Asami

From 50 to 42 is a drop of 16%. That seems quite large to me. An 8% drop is acceptable to me but maybe I'm an idealist.

Reply to
Oumati Asami

replying to trader_4, Iggy wrote: So, you think the spring (not a rod) is there to do nothing?

Reply to
Iggy

It means it maintains the output pressure near what it's set to regardless of whether the input pressure is at that pressure or much higher. The whole purpose is to maintain near constant pressure. Again, I believe your question was whether they work like:

A - Maintains a fixed reduction value, eg 20 psi below whatever the incoming pressure is. (This is what you say the guy told you) So if the incoming is 100 and it maintains a 40 drop, you'd have 60 on the house side, but then if the incoming drops to 70, you'd have 30 PSI out.

B - Maintains a fixed output value, eg 60SI, regardless of incoming pressure, as long as the incoming is 60+

They work like B, they will keep it close to 60. The A type I've never seen and if they exist sound pretty worthless when you have the B type available.

Reply to
trader_4

What are you basing your conclusion on? Is it because 8% sounds better than 16%? I'm basing it on operating a manufacturing plant with air, steam, city water, recirculated water. We probably had 30 or 40 pressure regulators. I often witnessed drops of 25% with no ill effects. It was a part of normal operations. Machines and appliances can take a wide variation unless you are doing some scientific experiments.

Reply to
Ed Pawlowski

A pressure reducer and a pressure regulator are just different names for the same thing. In a Navy fire room we called them reducers. All were constant output pressure when operating. That "engineer" made no sense.

Reply to
Vic Smith

There should be no significant variation. It's a pressure controlled valve, as the output pressure approaches the set value, it closes. You might see a pound or two variation, but it should still be very close to 50 and not matter from a practical standpoint.

Reply to
trader_4

We don't know which particular device you have or how it's put together. What's the problem and what are you trying to do? Taking a bolt with a spring out and having the spring come with it doesn't sound unusual to me.

Reply to
trader_4

The types of regulators we are talking about all work by REDUCING the pressure.

If the regulator is set to 50 and the incoming pressure is 25, the "regulator cannot increase the pressure, it can regulate in one direction only and that is reducing.

That's probably what the engineer was trying to say.

mark

Reply to
makolber

Home Depot's web site has a lot of them - after you click on the product - there is a link to "specifications" that might help. ... graphs for flow characteristics; pressure ranges and limits, etc Here's just one example ..

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John T.

Reply to
hubops

No. That's not what he tried to say. I told him the output pressure should be constant. He said no. He said the output pressure would be affected by the input pressure.

He also said the lowest pressure the devise could set to was about 48 psi. I really doubted it. That seems to be quite high for residential water pressure (not that the pressure is quite high but the lower limit is quite high). I would think the device could reduce the pressure to 20 psi or lower. But then, I really need to find out the model number and check the literature.

Reply to
Oumati Asami

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