# Sprinkler head question?

Discussion in 'Irrigation' started by FIREPLUG1111, Mar 18, 2009.

1. ### FIREPLUG1111LawnSite MemberMessages: 114

I'm getting ready to install a irrigation system in my yard. My question is-- the rainbird rotorary head sprinklers I have, have a 3/4" inlet. I was going to run 1/2" pipe to the head. ( downsizing as I go along starting with 1") Do I need to run 3/4" pipe to the heads or will 1/2" work?
Thanks Alan

2. ### TRILAWNCARELawnSite Senior Memberfrom One Foot in the GraveMessages: 946

How many heads per zone are you planning on running and pressure will answer the question of what size the pipe needs to be?

What are the specs for your system static pressure, GPM, Pressure loss, type back flow device, number of zones, number of heads per zone, distance for each zone and so on..... Or did you not figure all this out yet?

3. ### Dripit goodLawnSite Bronze Memberfrom Southeast MichiganMessages: 1,081

No need to downsize, save yourself the trouble. Your working pressure will be better if you don't. Stick to 1" on all your runs.

More importantly are you going to answer TRI?

Did you do your homework??

4. ### TRILAWNCARELawnSite Senior Memberfrom One Foot in the GraveMessages: 946

But I was watching the Sprinkler Daddy video and....................

5. ### FIREPLUG1111LawnSite MemberMessages: 114

TRILAWNCARE:
I'll try and answer your questions.

#1 Each zone will have a different amount of heads. That is determined by the area they are covering. Example. My side yard will only have 5 heads all with 1/2 radius coverage. My back yard will have 9 heads 4 of which will be full radius and 5 will be 1/2 radius.
#2 Pressure, My pressure will be between 50 and 65 psi . My pump is putting out an average of 35 GPM at the pump.
#3 Friction loss FL=C,Qsq,L. That cant be determined until water is flowing.
#4 No back flow device its on a well pump.
#5 Not sure how the number of zones determine the size of pipe. But I have 7 zones.
#6 See #1
#7 See #1
#8 distance to the farthest zone is about 155 feet.

6. ### FIREPLUG1111LawnSite MemberMessages: 114

DRIPIT GOOD:

Thanks for your answer short and to the point. I will run 1" pipe and hit the heads with 3/4"

Thanks for your answer.

Alan

7. ### Stuttering StanLawnSite Bronze MemberMessages: 1,504

Assuming you did the design correctly, will you have a matched precipation rate throughout every zone? If you don't know what ths means, do more homework. It's vital to ensure a quailty system.

8. ### unit28LawnSite Bronze Memberfrom MN, A-noka CO.Messages: 1,554

If you don't get #3 before you do #1 then I would get someone who can do #2 to flow better.

9. ### FIREPLUG1111LawnSite MemberMessages: 114

Stan:
Yes I did my calculation on precipation rate. The half radius heads will have a different size nozzle compared to the full radius nozzles. Most likely half the rate on the half radius compared to the full radius. I dont want puddles on my half radius coverage.

10. ### FIREPLUG1111LawnSite MemberMessages: 114

UNIT28:
My pump is pretty much a constant I really cant change that. I can only suck so much water out of the ground at one time.