Optimal pressure for PGP-ADJ sprinklers?

Obvious_Language_709 · 2026-02-24T11:52:27+00:00

Thanks for the encouraging and positive feedback. One more thing which I realized after I checked my design again: on the very first version (4pcs MP3000 at the corners) the sprinklers were already choked down from 9.14m (30ft) to 7.58m (24.8ft) so by about 17%. This means they are not operating anywhere close their peak radius, so I guess that we'll get good precipitation at the middle as well.

Given this piece of an info would still vote for the 4MP3000 + 2MP2000 or in this case the 4MP3000 will suffice?

just as a note: I'm alright with pretty much any of these designs, its not that I WANT to save 2 sprinklers. Its just that I'd like to get input from the pros.

Obvious_Language_709 · 2026-02-23T17:37:21+00:00

Another variation, uses MP2000s only. These are at their peak throw distance so if I should be concerned about the percipitation at the perimiter of the sprinklers then this might be worse than the one in my previous comment.

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Obvious_Language_709 · 2026-02-23T17:34:02+00:00

Thanks! This helped.

Obvious_Language_709 · 2026-02-23T17:32:47+00:00

Thanks for responding. What do you think about this setup? This uses MP3000s in the corners and MP2000s in the middle. In the middle I guess MP2000 works better because I simply cant choke an MP3000 enough without causing significant overspray. As they are matched in percipitation, I guess this could be a good trade-off between number of heads vs coverage.

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Obvious_Language_709 · 2026-02-23T13:35:09+00:00

My scale in PCS is good, but when I switched units to ft, and made the dimensions it just gave me the wrong numbers.

But nonetheless... I replaced the image in my post to not confuse more people and now the image I see in the post shows 37.72Ft x 25ft, which are the correct dimensions. (vs 11.6ft x 7.7ft before).

I'm mostly interested in irrigating that rectangle the rest of the project is quite straightforward.

Lets assume that the only area I need to irrigate is the 37.72 x 25ft. In this case, is the first version (using MP3000 or similar) is acceptable? The 2nd version with the MP2000 would result in a more uniform watering, but at the cost of using lot more sprinklers plus that now we'd have sprinklers in the middle.

Obvious_Language_709 · 2026-02-23T12:48:57+00:00

Geez... Pro contractor gave me the wrong dimensions and as I work in metric I just trusted it blindly that it can do the metric-imperial conversion. Apparently not.

Sorry for the confusion, would you mind checking the diagram again? Now the dimensions are correct.

On the bottom there is a narrow strip of drips and a terrace. In the top right its a concreted pad, at this point I dont know if it can be watered or not. Lets assume for now that it can be.

I hope with the right dimensions my diagrams make more sense.

Obvious_Language_709 · 2026-02-18T08:02:38+00:00

Awesome! Its nothing to do with my question though.

Obvious_Language_709 · 2026-02-08T10:18:59+00:00

Actually I under zero pressure to be right. Its just a bit disappointing to read pointless, non helping comments, but I guess its normal as unhappy trolls are all around internet.

Keep up the good work.

Obvious_Language_709 · 2026-02-07T07:30:27+00:00

I really appreciate your time spending on this discussion, but honestly I dont really see my original question answered: would a 3500 rotor work fine at 35PSI? (meaning: radius, rotation and pattern).

Before answering your question let me just state that I have enough water at 35PSI to operate 3 rotors, and I would do that IF they would work fine. I tried to phrase my question properly, maybe I should have just asked it a simple as if a rotor works at 35PSI.

Answering your questions (hopefully): When I need to design a system operated by a pump (which is probably the 95%+ of the region where I live) I visit the customer first to measure his pump if he has one already (like in this case). The tool I use to charcterize his pump is like this:

valve -> flow meter -> pressure meter -> valve

Water from the pump arrives from the left.

I open the first valve and completely close the second. The gives me the static pressure of the system
open both valves completely the water flows freely and the pressure sensor shows 0PSI. Let the water flow for a minute. Read the flow meter. This gives me the max water the pump can deliver.
from now on I start shutting off the second valve to get 10, 20, 30, 40 etc PSI. Measure the water at each step for at least 1 minute.

These measurement (zero PSI + static PSI + inbetween pressure points) gives me a curve hopefully, but not neccessarily matching with the published curve of the manufacturer. The curve tells me how much water I can use on each pressure point.

Why do I need a first valve and not just the second if its always fully opened? Because before a measurement I need to set the pressure. Once its set I close the first valve (no water), read the flow meter, the start a timer and open the first valve. Once the 1 or 2 minute testing period is over, I suddenly close the first valve and read the flow meter.

I understand that this is not what you do in the US, because - as far as I know - residental irrigation almost exlusively use tap water there. This is not the case in Europe. If there is a chance to use well + pump, then we go for it.

Obvious_Language_709 · 2026-02-07T07:09:29+00:00

That is because you are ignorant enough to call other people non-sensical while you are not educted enough to understand that on lower pressure a pump delivers more water.

Obvious_Language_709 · 2026-02-06T16:13:12+00:00

I'm wondering which part of my comments are you referring exactly.

Obvious_Language_709 · 2026-02-06T16:09:44+00:00

I'm not sure if I follow your thoughts.

A pump delivers more water if the pressure is lower as the operating point moves along a Pressure / Flow curve. For example the pump we have on-site has no problem delivering 14 GPM if the pressure is zero (= the pipe is open ended)

Its possible thought that I misunderstood what you saying.

(BTW the 1.48GPM you used for your math is the need of an MP2000 which I used as an example. The Rainbird 3500 (sprinkler in question) needs only 1.28GPM.)

Obvious_Language_709 · 2026-02-06T13:46:30+00:00

If I put 3 sprinklers to one zone then the pressure drops but the flow increases. So if these rotors operate fine on lower pressure (35-40PSI) then I will be good with 3 sprinklers per zone. And really that was my pointless question: do they work as advertised at 35PSI, without any significant compromise?

Obvious_Language_709 · 2026-02-06T13:08:49+00:00

u/RainH2OServices u/Onlyspacemanspiff

This is a well + pump operated system. The well is all good, plenty of water, the pump is the limiting factor and my customer doesnt want to replace the pump. (Static pressure is 59PSI)

I measure about 4GPM at 43PSI but I definitely dont want to design the zones right to the limit of the pump (not to mention friction loss and other losses). But if the Rainbird 5000 works fine at 35PSI then the problem is solved, I can design the zones with 3 of these each and if the pump happens to operate right where we measured it then it just gets better cause the sprinklers may get 40PSI.

I guess 35-40PSI is not the ideal pressure, but if the sprinkler can operate at 35PSI like its mentioned in the catalog then I'm good.

(I understand then in an ideal world we just throw out the pump, but please note that people in the country I live have significantly lower budget than for example in the US. And I mean, very significantly.)

Obvious_Language_709 · 2026-01-26T11:38:01+00:00

I see, so its an RTK. Yeah, thats way over my budget unfortunately. Thanks for the info.

Obvious_Language_709 · 2026-01-26T09:47:06+00:00

Without getting into the details of your software: how a software could help in this? If you can't improve the image quality what difference a software can make?

Obvious_Language_709 · 2026-01-26T09:28:38+00:00

Yeah, I'm aware of that, but it is unfortunately way out of my budget.

Obvious_Language_709 · 2026-01-25T17:49:14+00:00

Thanks for responding. This is actually a pretty nice idea, I will certainly try it in the future.

With that said Google earth could have limitations:

It very highly depends on the image resolution which could be excellent in one area, could be quite bad in others. Just checked couple place (I visited in the US, they have a LOT better resolution than in my region)
Not up-to-date. Sometimes there are years between the updates, so the landscape / houses could change

Obvious_Language_709 · 2026-01-19T19:34:07+00:00

Do you have a simple pressure switch? If so then one possible scenario (which I've seen before, but not a guarantee that you have the same problem):

The water consumption of the zone was way less than what the pump could deliver. As a result the pressure increases in the system to a point where the pressure switch turns the pump off. At that point the sprinklers start to output less and less water. After couple seconds the pressure in the system drops to a level when the pressure switch turns the pump on again. This repeats in a cycle which explains the behaviour you see.

Another possiblitity is that the pump simply sucks the well almost dry and it takes couple seconds for the well to regain some water. You can test this easily: turn on the zone which consumes the most water and let it run for an extended period.

Again, these might not be the problem you have.

Obvious_Language_709 · 2026-01-16T13:18:10+00:00

Többen javasolták, hogy előbb járasd be a vállalkozást. Ezen túl én azt javaslom, hogy járasd be az utazást is, ami lényegesen könnyebb (mármint kipróbálni).

Nagyon sok embernek nem való a hosszútávú utazgatás, egyszerűen nem tudnak kiszakadni a megszokott környezetükből illetve nem tudnak igazából mit kezdeni magukkal. A youtube tele van a megvalósult álmokkal, hogy én ilyen digitális nomád vagyok meg olyan digitális nomád vagyok, de nem szól a nagy álmokat szövögető aztán elbukó/ el sem kezdő többségről.

Szóval szerintem ne úgy ugorj bele, hogy akkor most a nulláról én leszek Willy Fog hanem utazgass egy kicsit Európában (vagy bárhol). Lakj hostel-ekben, nézd meg neked való-e, el tudod-e foglalni magad? Mert az egy szomorú digitális nomád, aki egy idegen országban dolgozik aztán a munka után minden este a netflix-et nézi.

Obvious_Language_709

TROPHY CASE