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Active Member


Friday, July 6th 2018, 1:30pm

New sprinkler system design

Hi i am installing a new sprinkler system in my new house and i am not
an irrigation sprinkler system expert so i would like some feed back and
suggestions on proposed sprinkler system set up.

My water will be from a well, at 61 PSI, 15 GMP.

I am proposing 3 zones, 1 front of the house and two in the back. I am
looking to go with Hunter's PGP-04 PRB but looking at the sprinkler
specks i would like to use the 3.0 nozzle to get 35 ft radius but when i
look at the sprinkler specs is see SPI say for 3.0, PSI-25, Radius -
35, GPM flow - 2.2, this doesn't fit my wells pump PSI of 61. Would this
be ok or do I need to add more zones and sprinklers, different

Also the main water lines can be 1 inch and the lines from the main line
to the sprinklers can be 1/2 inch or can they be all 1" from the main
line to the sprinklers?



Active Member

Posts: 42

Location: Washinton


Friday, July 13th 2018, 5:44pm

When on a well an pump you want to make sure you don't put out to much water or too little. If you put out too much your pump may begin to cavitate or you will just lose pressure.

Too little and you pump will be turning on and off repeatedly. You want to design your system so that your pump is running at about 35-45 psi with a constant flow of water.
To do this open a faucet connected to the pump regulate the pressure to 35-45 psi and see how long it takes to fill a 5-gallon bucket. Then some simple math will tell you your GPM at that pressure. For example, it takes 30 seconds to fill the bucket 60 seconds divided by 30 (how long it took to fill the bucket)=2
This translate into 1 minute you can fill 2-5 gallon buckets, therefore, you have 10 GPM (Gallons Per Minute)
Now that you know how much water you have you can layout your zones accordingly.
Pipe sizes- for residential systems I always used 3/4 poly pipe and 5/8" flex pipe to the heads. This helps to keep it simple and minimize the number of fittings you need to buy. Also 1" poly pipe is a lot harder to work with.
Hope this answered your questions.


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