Water Pressure Regulator - Good idea to reduce by 50 psi?

[Mike]

My dad's house was built in 1978.

When my dad had to have a water heater replaced in 2016, the plumber told him the water pressure was very high, at 115 psi, and he should install a pressure regulator where the water supply comes into the house, and that would be less stress on the appliances and faucets. I didn't know if the plumber was just trying to get more work or not. The water pressure has been 115 psi for as long as I know, with no problems. I called the water department, and they told me yes it is 115 psi in his location.

He likes the water pressure because the lawn sprinklers squirt far. If he puts in a pressure regulator, I see that they are adjustable, generally up to 75 -80 psi. That's a big drop from what he has now.

The all brass automatic sprinkler valves are starting to leak, and need to be replaced. Since they are next in line from the water supply line/valve to the house, he thought that if he was going to replace the sprinkler valves, which require removing the main valve to the house, he might as well have the regulator installed too.

Will this big drop in pressure cause any of the seals/gaskets in appliances/faucets which have been under 115 psi for years, cause the seals/gaskets to 'back off' and not be held as tight anymore?

In my own home, the pressure is 65-80 psi, and all works well.

The red knob is the supply valve from the street to the house. This valve sounds a little crunchy when rotated, but doesn't leak. The blue knob goes to the manifold for the four automatic sprinkler valves. Originally manual sprinkler valves, and at some time auto-actuators were added. One valve leaks at the diaphragm and another leaks at the non-pressure connection.

[dpb]

...

40-60 psi is considered a normal range; regulators generally are preset at 50 psi.

Reducing the pressure won't cause leaks that weren't there before, no.

Outside pressure higher than inside wouldn't be a bad choice if you could manage the arrangement conveniently.

[trader_4]

+1

And IDK why replacing sprinkler system components requires turning off the water from the street. The red valve shuts off all the water, the blue valve for the sprinklers is after it. I guess since the main valve is old, probably a good idea to change it anyway. Depending on the sprinkler layout and range, reducing that pressure could be an issue or not. But even there, if there is an issue, good chance you could have a higher than normal system pressure, eg 75, but still have the sprinklers work OK. On the other hand it's been high for a long time with no problems. One issue could be that any new things added, eg refrigerator with ice maker, may not be designed to handle it and they make all these things cheaper than they used to, so it could be an issue with some new component someday.

[gfretwell]

That sounds strange. 40-60 might be normal for a well but plumbing fixture flow rates are based on 80 PSI. I got into this with the tech rep at Price Pisser over a kitchen faucet that was putting <2 GPM and was rated at 3. (Still damn slow if you are filling a sink or a big pot)

[gfretwell]

Most things are rated at 100 PSI or so but stuff like pipes and valves should be able to take much more than that. Even garden variety white PVC is rated 480 PSI. Copper and galvanized, more than that.

You are right, I would be pretty nervous about that milky vinyl tubing most people end up with behind the fridge but I haven't used it since I had one break and flood the house. Fortunately this house had terrazzo floors so the damage was minimal. It was pitched so most of the water went out the slider. The cabinets had real wood kicks.

[Dean Hoffman]

On 8/10/20 12:33 PM, [e-mail] wrote: Some cut.

That 480 psi must be a typo instead of a dummy attack. I repaired center pivots where gallonage ran in the area of 700 gpm and pressure at the center point was around 35 psi. End pressure was supposed to be around 20 psi. That would be about 1300 feet away with 6

5/8" pipe. The pivots were often supplied with buried 8" pvc pipe rated at 80 psi.

[Scott Lurndal]

Yeah, must be a typo. The piece of 1/2" schedule 40 PVC pipe I have in my hand is printed with 600 PSI at 73 degrees Fahrenheit (and a manufacturing date of 1988).

[dpb]

It goes down by size... Sch 40 is

1/2 600 3/4 480 1 450 1-1/4 370 1-1/2 330

The derating with temperature above 73 F goes down pretty quickly, too, so for hot water @ 0.5 for 110 F it's starting down the road...at 120F the derate factor is 0.4 and 0.2 at 140F.

[gfretwell]

1/2" sched 40 is 600 PSI, 3/4" sched 40 is 480 PSI

Regular white PVC is the 3d yellow column.

[gfretwell]

3/4" is 480. That is usually the largest you see on the pressure side in a dwelling. CPVC has a similar rating.

[Dean Hoffman]

Well, I never would've imagined pvc pipe was that strong. I wasn't planning on it but I learned something. I got curious if what we'd always called 80 psi pipe was that. I looked up the supplier to see.

[gfretwell]

That is why homes will be piped in CPVC that has better hot water performance although PEX is taking over these days. I assume in some mobbed up union states they still use copper but I seldom see it here.

[gfretwell]

Even the thin wall PVC they use for sprinklers is 200 PSI.

[KWills]

WHAT A GODDAMNED DUMBSHIT!

[invalid unparseable]

On Mon, 10 Aug 2020 18:45:59 -0400, [e-mail] posted for all of us to digest...

Man o man they got the stuff!

[invalid unparseable]

On Tue, 11 Aug 2020 13:05:03 -0400, [e-mail] posted for all of us to digest...

PVC is not to be used for air piping; I assume because of impact damage?

[gfretwell]

Just the fear that if it bursts, little pieces will fly everywhere. I ran galvanized in my shop but I had UV protected (RNC) run around there for years. I really wanted someone like Myth busters to try this but I couldn't get a bite. I even offered them some PVC that had been out in the Florida sun for 25 years or so as a grape arbor. I really think it is lawyers more than anything. Everyone knows a guy who heard a story about a PVC pipe exploding but it is pretty hard to track that guy down.

[invalid unparseable]

On Wed, 12 Aug 2020 21:15:26 -0400, [e-mail] posted for all of us to digest...

I wondered about that. Another urban legend. I looked at the site and it didn't mention anything about it. I saw on one of those car shows that renovated auto shops where they were using some blue coated (which looked like PVC) lines with some sharkbite type fittings.

[gfretwell]

It may have been PEX. I think that gets an OK from everyone but the purists because it will just split open, not shatter. Other than cost, the galvanized wasn't a big deal to do and it should last forever. I ran 3/4" trunks and 1/2" drops to each outlet. I have about 7 of them around the shop so you are never far from air with 3 hose reels. One on each side of the overhead door and one by the side door. The only maintenance with them is the "O" rings every year or two..

[invalid unparseable]

On Thu, 13 Aug 2020 16:48:42 -0400, [e-mail] posted for all of us to digest...

My wife and I would entertain an offer to move in but you graciousness would go to waste because I could not take advantage of it... ;-)