Have Great Pressure but Sprinklers Are Not Performing? | SprinklerSupplyStore.com
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- Опубліковано 13 лип 2024
- Do you have great water pressure but your sprinklers are not performing?
In this video, Andy talks about the 2 key components of pressure which are known as STATIC water pressure and DYNAMIC water pressure. These terms are important to understand as it relates to designing an irrigation system or troubleshooting an irrigation system, especially when it comes to pipe sizing and knowing how many sprinkles to put on a zone.
00:00 Introduction
00:10 Static vs Dynamic Water Pressure
01:27 What is static water pressure?
03:20 What is Dynamic Water Pressure?
05:30 How Much Pressure Is Lost In A Sprinkler System?
06:43 How do you calculate static pressure in an irrigation system?
09:59 Static Pressure VS Dynamic Pressure
10:36 Outro
Pressure Loss Charts (courtesy of Hunter Industries):
👉 sprinklersupplystore.com/fric...
Summary:
#1 - STATIC Water Pressure:
STATIC water pressure is the pressure on the system when the water is motionless - when the water is not moving - when everything is turned off. You can measure the STATIC water pressure using a pressure gauge attached to the hose bib on your home, and you will need to make sure all the water in the home is OFF.
STATIC water pressure is the pressure when the water is motionless and what's important to know is that in a level piping system, STATIC water pressure is the same everywhere - the pressure is the same at the beginning of the system as it is at the same at the end of the system. The only difference in pressure is going to be due to elevation changes - the pressure at the top of the hill will be lower than the pressure at the bottom of the hill because of the force of gravity. Gravity is the only force that can change STATIC water pressure. Pressure loss or gain due to gravity is about ½ pound per foot of elevation change, or to be exact, it is actually 0.433 lb/ft.
#2 - DYNAMIC Water Pressure:
DYNAMIC water pressure is measured when the water is moving. This is also referred to as OPERATIONAL pressure or WORKING pressure, and it is the pressure taken at any point in the system while the irrigation system is running. The reason that you want to understand this concept is that when water moves through a pipe, it is affected by the components of the piping system, as well as the size of the pipe. Devices such as water meters, backflow preventers, and sprinkler valves, all create FRICTION, which reduces the DYNAMIC water pressure. The size of the pipe will also create friction and reduce the DYNAMIC pressure. This concept of friction is commonly referred to as FRICTION LOSS, or, DYNAMIC pressure loss due to friction.
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What would you recommend if the installer used 1/2” inlet pgp rotors? They’re hunter copy’s with the installers name on them.
I had to swap out the guts only when I’ve replaced the head from damage.
Ended up adding a booster pump on our house in a city. Static pressure is 70 at the pump.
Pro sprays wouldn’t pop up until we added the booster. Recently had to switch the order of zone 3 & 2 of pro sprays around on the controller because 3 wouldn’t pop up after 2. Now they do… so confused.
Pgp copies with new hunter guts don’t really reach head to head coverage in several areas.
Main line underground is black 3/4 I believe. 10 zones.
Would I try all 1.5 gpm nozzles on my pgp? Or buy a different sprinkler head for the rotor zones? What about rotators on my system?
Any help would be greatly appreciated.
Happy to help, and if you’re interested, you can book a Zoom call with me and walk me around your system so I can see your setup.
calendly.com/andyhumphrey/technical-support
First - PGP rotors have a 3/4” inlet. Wondering if perhaps they are not PGP (type) sprinklers, but maybe the smaller PGJ model, which is 1/2”.
Hunter does not make custom branded tops (that I’m aware of), however, K-RAIN does, and the sprinklers are almost identical.
Either way, it sounds like you have a pressure problem, and the type of sprinkler is kind of irrelevant as you can change the nozzles, like you suggested.
Knowing that you have a pump makes me think you may have a restriction in your mainline somewhere. Tree roots can sometimes squeeze black poly pipe and cause this.
Or, your water source isn’t adequate for the number of sprinklers on each zone.
Or, the service line feeding your house is being restricted. Old galvanized pipes commonly corrode on the inside and restrict flow. If your home is less than 20-30yrs old, this is probably not the problem.
My recommendation is to get a pressure gauge and test the dynamic (operating) pressure of the sprinkler. Based on that, you can work backwards to determine if the mainline pipe is restricted.
There could be a few others issues and things to check we could go over on a call.
Here’s a link to learn about the MP GAUGE. You should buy one, and then we can help you from there.
ua-cam.com/video/LvcGzMgoXJk/v-deo.html
Thanks! I’ll start with the mp gauge.
I’m fairly certain that there’s a kink in our main line. After all that’s why we went with a booster pump. House is only 7 years old.
Kink is Possibly at the curb stop.
Just not super excited to dig up my yard looking for a needle in a haystack.
@@pagodad8079 I agree with this. Testing the pressure at each zone will help you figure it out. Zones before the kink should have proper pressure. You should be able to determine the approximate location in between 2 valves.
Got the mp guage. Zones two and three on my system are hunter pro sprays.
When taking a reading from zone 2 & 3 separately they start at 20psi and tend to drop off from there gradually; Eventually sustaining pressure around 15psi.
I wonder if my booster pump ends up having trouble keeping up? These zones are closest to the backflow preventer where the water comes out of my house as well.
Luckily where I have the sprays even this lower pressure isn’t enough to keep them from watering the narrow space they’re intended for.
The confusing part is I had to switch the order in which 2 & 3 start to get 3 to pop up.
Another part of this mess. Does this also tell me why my pgp rotors aren’t performing to their full potential and would you recommend I use 1.5 gpm nozzles on every rotor head?
@@pagodad8079 could be. I think it depends how the booster is setup. Do you have a pressure tank? Some pumps kick on, then pressurize, then turnoff, then turn on again, and repeat. It really depends on the setup.
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This video would have been very helpful two years ago when my irrigation system started performing poorly at the beginning of the new season. When I bypassed the well pump and connected the system to the city water supply, it worked great. I called in the company who drilled the well and installed the system to fix it. After a day of head scratching, and fitting two different pumps with no improvement, the techs left for the day. I dug out my Hunter MP gauge and checked the pressure on one of the zones using the well and city water. In each case, the static pressure was great, but the dynamic pressure when using the well was very low. The dynamic pressure on the city water was great.
The problem was an undocumented, and previously unknown to me, silt filter built into the main shutoff valve in the valve body box. The valve is part of the pump piping and just before the Hunter zone valve manifold connections. The filter was nearly completely clogged and was restricting the water flow from the pump. The city water connection was after the filter in a different point of the valve manifold. After cleaning the filter, the pump dynamic pressure to the zones was perfect.
Yep, that'll do it for sure, makes total sense! Pretty interesting how static pressure doesn't tell the whole story, it's more of an indicator of "potential" pressure. You might have 50psi...or you might not!
Thank you!
My pleasure!
Gracias Sprinker Nerd Andy, great vid!
Thank you!
I'm Glad I stumbled across your video! I was thinking the new "shrinking non kinking" hose was the problem.. I'm trying to get temporary irrigation about 250 feet out for my grass/landscape proj but it just trickles and it's slightly up hill from my bib... I was thinking hard conduit would help the prob but you have caused me to re think it.. I was about to pay the county to install a second supply/meter if all else failed. Incidentally, I'm trying to water back up the hill close to the meter lol
Cool Video, All The Best!
My pleasure. Yes, it sounds like low pressure due to friction loss through the hose. Here is another video that might be helpful: ua-cam.com/video/7UfDL2IlVMA/v-deo.html
So weird, I changed out my rainbird 1800 PRS bodies with 17-24 rain bird rotarys to Rain Bird 32sa rotors. The rotors have awesome pressure now, on some of my rotary nozzles it could not achieve the same uniform coverage as the rotors now do.
Good to know. Rain has the sweet spot for pressure listed as 45psi for the R-VAN rotary nozzles - so my bet is you have less than that, maybe 30-40psi, which is okay for the 3500 series (32sa box store model). Curious if you know what your pressure is?
Great channel man!
Do you have a video to fix what I think is called hammering?
I woke up when my sprinklers were going at 10pm because there was a loud rhythmic thumping/hammering sound. Next morning the sprinklers went off at normal time again and I saw all my sprinkler heads bouncing up and down coupled with the hammering/thumping sound (this was happening one zone at a time).
I purged the system by shutting off the water supply, running the system and then finally, slowly re-starting the water supply. Oddly, the system started on zone 2 and seemed to have been corrected as all the zones ran normally. Just to be sure I ran it again- this time it started on zone one and ran perfectly but, when it went to zone 2 the hammering was back.
Any chance you know what to do?
Thank you for sharing all of this information.
It’s possible that one of your zones, or many, we’re not closing all of the way, and the diaphragm in the valves were opening and closing very quickly as if flapping.
I would look for patterns, was this a one time occurrence, has it happened again, is it still happening, etc.
I may not be a pressure problem, could be something else.
Could a plastic rain bird in line sprinkler valve make my dynamic pressure too low to pop up sprinkler heads? I hear a slush when I turn on the valve. It registers 130 lbs of static pressure after the valve but I’m wondering if the valve is stopping dynamic pressure. Have you heard of this?
Yes, it can, if it’s not opening all the way. It could also be a kinked pipe, in the same way, restricting flow.
If your valve has a flow control handle, make sure it is all the way open.
I have 13 heads going at once @ 120 psi or round are about, they pump out a lot of water fast , I've had contractors tell me that it's not effective with that much pressure, I've been watering twice a day 12 minutes total and my grass is green and tall.
Congratulations, you are both correct ;)
If your grass is green, that is the goal, and it's working!
120psi is very high and over time this could cause problems, mostly, shortening the life expectancy of the piping and fittings.
Otherwise, high pressure causes the water droplets to be smaller, which more easily causes wind drift and increased evaporation to the air, leading to overall inefficiency.
In summary, inefficiency just means you have to use more water (water longer) to achieve the same effect.
Pressure regulators are not expensive and if it were me, I'd put one on your mainline.
Friction loss is a big part of why I use 1.5 gpm nozzles whatever the arc is
Great point! Sometimes the GPM is more important than the distribution uniformity. This is not a laboratory, it’s a Landscape, there’s room for creative thinking.
Zone 3 on my grandma’s irrigation system has 4 pgp ultras with 3.0 standard angle nozzles but when I take out the nozzle on one, the others have no drop in pressure, so the idea of them using the same gpm with tons of pressure is stupid although 99.2% of the grass covered on that zone is a deep green so I have left it like that
Been to a lot of houses with issues like this. People will replace their own heads and put the biggest nozzles in their heads. I’ll just take the nozzle out and put a smaller one in. Like for a corner I’ll use either a 1.5 or 2.0. You don’t put a 6.0 on a head in the corner.
haha, exactly!
Yeah even I know the correct nozzle for each spot but if you put a 4 gpm on a 90 then your zone should only be 180’s and 90’s so the 180 is 8 gpm, I think you get my point, although I also have a rule for lower pressure that might be hard to understand
@@BRISTOLFORCE2009 I only use 4.0s on 360s with really good pressure. But some people use those nozzles on zones with 6 to 7 heads and they complain about low pressure.
@@AD-vf3ek my thing about low pressure is use the same nozzle in all spots and that should be 1.5
@@BRISTOLFORCE2009 yeah. Sometimes id you’re client is in town water then you can recommend a booster pump.