PDA

View Full Version : what is wrong here?? any ideas???


jonspolaris
07-13-2001, 04:40 PM
My mom lives in a condo subdivision, its on 4.5 acres. All the grass area is irrigated. The contractor that installed the irrigation used hunter PGP heads. Each head covers a good size area. The main feeding the system is 2Ē in diameter and is city water. The problem is that there are MANY large brown areas that arnt getting watered, and the system runs for 20 minutes each day. In these areas the grass is very dry. Some zones have 30 (yes 30) sprinkler heads on them. I think the problem is that there are too many heads and not enough water coming out of each head. Some of the heads look like a little kid peeing, they just donít have much volume.


Am I correct?? Any ideas?? thanks

racerdave
07-13-2001, 05:12 PM
jonspolaris, I think you are on to something there.

You need the gpm requirements for the heads, and also know the pressure and flow of the supply water to determine how many heads per zone you can run.

Plus you need to know the pipe sizing for figuring frictional piping loss also.

when on city water you also have to take pressure fluxuations into account. In other words if a bunch of your neighbors are also trying to water at the same time you are, then you will have a much lower pressure to work with.
good luck
david

jonspolaris
07-13-2001, 08:19 PM
Originally posted by racerdave
jonspolaris, I think you are on to something there.

You need the gpm requirements for the heads, and also know the pressure and flow of the supply water to determine how many heads per zone you can run.

Plus you need to know the pipe sizing for figuring frictional piping loss also.

when on city water you also have to take pressure fluxuations into account. In other words if a bunch of your neighbors are also trying to water at the same time you are, then you will have a much lower pressure to work with.
good luck
david


thanks dave,


i think the heads put out 6-8 gpm, but im not positive. The zone accross the street from us works great, they have VERY good flow. On that zone there is 14 heads, down the street there is another zone with 30 heads covers a VERY big area. the 2" main is about 650' long and is the same diameter the whole length.
I think the zones at the end of the street are getting the"short end of the stick" in terms of pressure. i think the pressure at the meter is about 50psi.

jon

Currier
07-13-2001, 09:40 PM
Is there any way to switch out the nozzles and reduce the volume of water gpm needed? The zones would have to run longer but maybe there would be enough pressure to at least get the place watered.

EarthWorks
07-13-2001, 10:52 PM
What is the spacing between heads. May be able to nozzle down and still get good coverage. 50 psi sounds low for a system like that.

Louis
07-15-2001, 07:38 PM
Check the head spacing and make sure that you have head to head coverage-meaning that each rotor hits the next closest rotor with the end of its stream.That may be why you have the rainbow dry area effect.Most manufacturers spec the heads for 50 psi up to 70psi.If you have that many heads you need to split the zones to have enough flow and they can do a good job at 3gpm nozzles unless thsy are full circle then they need to be 6gpm.Hope this helps.

John DiMartino
07-15-2001, 09:07 PM
The Hunters have screens in the bottom,when mine plug up partially,they spray weak,ID check the system pressure in the pipe,and clean the screens on a few heads,see if they have algae buildup or rust/scale build up first.

Avery
07-15-2001, 10:55 PM
Like John said..check your screens. If that is not it you probably need to drop the gpm inserts in the heads. 6-8 gpm is huge for that type of system. Audit your system and see what type of coverage you are getting. Put some rain gauges out, run the system and see how much water it is putting down in a cycle.

jonspolaris
07-16-2001, 09:10 AM
thanks Guys,

How do i check the screens in the heads???

i was watching a zone today and it was pathetic. the heads just shot out a stream that landed in a small area, it dident blast out of the heads. The coverage isnt that good becaues there are many backyards with brownspots from being dry. It hasent rained in 2 weeks here. Most of these zones u can see that the lawn is green where the stream lands and then brown in the middle.

i would guess there 20-25ft apart in spacing. i still think the problem is to many heads on at one time.

the system is running for 40 min a day ( 2-20min cycles) and there is still brown spots. i just think there isnt the quanity of water going on the lawns that is needed.


does anybody know how much water u can get out of a 2" water line hooked up to the city water line?? we are very close to the water tower, and presser is good here.

thanks

Chuck Sinclair
07-16-2001, 09:40 PM
Bottom line is you are correct you can NOT have 30 PGP rotors on one 2" valve with 50 psi at the meter. even if you change the nozzels its not going to make a differance.:blob3:

John DiMartino
07-16-2001, 11:27 PM
You can go down to a 3-4 GPM nozzle,it wont be right,but it will make a diiference,the line pressure will be almost double of that if the 8 GPM tips are in there,so the water will go further,and atomize better.Ity wont solve the problem,but it will help,and its worth the effort to me.To clean the screens,you unscrew the head by tuening the external nut counterclockwise,until it pops out of the base,the pull out the head,and at the very bottom ,there is a small metal clip on a plastic nub,grab onto that with some needle nose pliers and pull it out,thats the screen,clean it good,reinstall,and check and adjust pattern with the service tool.

HBFOXJr
07-18-2001, 08:30 PM
Go to HunterIndustries.com. They have a ton of downloadable information about design and other specifications.

You haven't supplied enough info to truly pass an informed decision.

If you have Century Rain Aid locally as a supplier get a catlog from them. It has a bunch of engineering info that would help.

Lastly, an irrigation system is supposed to be an engineered product. Irrigation engineering is a discipline to be learned and mastered.

Get a thorough education before attempting anythins or you'll be no different that the incompetant people that installed/maintained this project so far.

booksmitty
07-13-2010, 09:32 PM
Your hunch is correct. typically 10 does it if there is good volume.

DanaMac
07-13-2010, 09:50 PM
Your hunch is correct. typically 10 does it if there is good volume.

Wow! Way to dig up a 9 year old thread. :clapping: Good job.

FIMCO-MEISTER
07-13-2010, 10:25 PM
Irrigators certainly were nicer back then. Polite and more polite.

WalkGood
07-14-2010, 12:49 AM
And I didn't notice if anyone said to check the valves or look for a leak.

Fireguy97
07-14-2010, 02:59 AM
And I didn't notice if anyone said to check the valves or look for a leak.

If it was a leak, (after nine years) either they found it by now, or the entire sub-division has washed away.

Mick

andyslawncare
07-14-2010, 04:45 AM
wow! We are guaranteed 15gpm out of a 1'' main line here... I do mostly residential, and do not know the volume for a 2'' main, but I'm sure its not 90gpm (30pgp with #7 nozzles=90gpm). On my 15gpm city lines we don't install more than 5 pgp's per zone! Some one is an idiot!

jvanvliet
07-14-2010, 06:21 PM
My mom lives in a condo subdivision, its on 4.5 acres. All the grass area is irrigated. The contractor that installed the irrigation used hunter PGP heads. Each head covers a good size area. The main feeding the system is 2Ē in diameter and is city water. The problem is that there are MANY large brown areas that arnt getting watered, and the system runs for 20 minutes each day. In these areas the grass is very dry. Some zones have 30 (yes 30) sprinkler heads on them. I think the problem is that there are too many heads and not enough water coming out of each head. Some of the heads look like a little kid peeing, they just donít have much volume.


Am I correct?? Any ideas?? thanks



Good grief, 30 heads on city water? What's your static pressure; flow rate; GPM... down here in SOUTH FLORIDA, i'm lucky to put 10 heads @ 2.5 gpm on city water.

JeffY
07-14-2010, 06:29 PM
The volume of a 2" mainline is approx 60 gpm at 6 fps. Can definetly do 30 heads of pgps if using number 5 nozzles or 2 gpm and have appropriate size lateral pipes. For me, I would just use larger heads such as I-35s if it were wide open spaces and there are no trees I would be blasting.

irritation
07-14-2010, 06:58 PM
. Can definetly do 30 heads of pgps if using number 5 nozzles or 2 gpm

You need to figure in about 3 gpm's extra per head for leaking seals/caps.

WalkGood
07-14-2010, 07:11 PM
For me, I would just use larger heads such as I-35s if it were wide open spaces and there are no trees I would be blasting.

At a condo subdivision, I doubt there is much wide open spaces. At least not enough to use larger than PGP and equiv. Probably a bunch of zig-zag turf areas.

jcom
07-23-2010, 07:03 PM
Did the system ever function properly? How old is everything? Would seem that if system was installed and did not work properly, it would not have been acceptable and not paid for.

John

WalkGood
07-23-2010, 07:31 PM
Maybe 2 zone wires are shorting together causing 2 zones of 15 heads to run at the same time.

FIMCO-MEISTER
07-23-2010, 08:23 PM
The thread is nine years old guys.
Posted via Mobile Device

CA Green
07-23-2010, 11:50 PM
Guess they are still having issues Fimco lol
Posted via Mobile Device

bobw
07-24-2010, 08:28 AM
Holy necro-bumb.... 9 years????? how the hell does someone even find a thread that old to bumb?

jvanvliet
07-24-2010, 11:54 AM
I must be doing something wrong; I can't get 30 Hunter PGP's to run on a single zone city water and get the coverage I need in 20 minutes even @ 2gpm's... but Then this is Florida.