Dear visitor, welcome to SPRINKLER TALK FORUM - You Got Questions, We've Got Answers. If this is your first visit here, please read the Help. It explains how this page works. You must be registered before you can use all the page's features. Please use the registration form, to register here or read more information about the registration process. If you are already registered, please login here.
You also have pressure losses starting at your connection in the street, which includes the house main line, the sprinkler mainline, your water meter etc. You will lose whatever wilkins stats in their literature.
You may want to look at irrigationtutorials.com there is a lot of info there.
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Tom</i>
<br />Your pressure is WAY TOO LOW! You will have a minimum pressure loss of 25 psi leaving you with 15 psi for the heads. Double check your pressure readings!
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Give me some details where all this pressure will be lost.
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Tom</i>
<br />You also have pressure losses starting at your connection in the street, which includes the house main line, the sprinkler mainline, your water meter etc. You will lose whatever wilkins stats in their literature.
You may want to look at irrigationtutorials.com there is a lot of info there.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Ok you say that you lose pressure through the connection at the street, main house line. That pressure loss is before the pressure gauge already so there is no need to subtract it twice from the reading????? [?]
the pressure reading Paterjb gave is static......the pressure losses I'm talking about are dynamic, that is when the system is running. For instance, I have 70 psi static pressure. When my system is running, I have about 45 to 50 psi dynamic pressure measured at the backflow.
If he starts with 40 psi static, he will lose 20 to 25 psi at the first head in his system.
Alright
The reason I question you is because I have basically the same setup. 115' mainline with 40 psi, and I still have 25 left to play with at the end head of each zone. I've installed many the same way also.
Tom I am not following the pressure loss either. I assume the reson your pressure drops is because of how many heads you are running at one time. If you turn on one faucet in your home does your pressure drop to 40-50? Now what if you turn on all of the faucets in your home? The dynamic pressure will be lower. I think paterjb will be fine.
Thanks,
Pete
You are right, but you also lose pressure through all the pipe and fittings from your sprinkler connection to the main connection.
Im saying that Paterjb has to account for all the pressure losses in his systems before he starts digging.
If he starts with 40psi he will lose at least 20psi(remember he has to install a psi robbing rpz) by the time the water reaches his first sprinkler head. Is this 20 psi enough to feed the heads on each zone? Spray heads will work at as little as 15 psi, but that is marginal. Most rotors need 25 psi to work properly. I think he needs to do a pressure loss calculation since his starting pressure is so low.
Peterjb,
Go to the Hunter Industries website at www.hunterindustries.com. Go to resourses and download the irrigation design calculator. This will help you best with the pressure problem.
im a little confused about all this pressure loss.....the design calculator is really helpful...and i would use RVLI's suggestion and go with that!
Thanks
Ray
Rays Above and Beyond Automatic Lawn Sprinklers
Do you really need an RPZ? If you use a PVB there is less pressure loss, only about 4-5 psi I believe.
SPRINKLER TALK FORUM - You Got Questions, We've Got Answers »
Help with Design & Installation »
Design Issues »
