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Pressure Issues

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atkinson4738

Unregistered

1

Saturday, June 21st 2008, 9:07pm

Pressure Issues

I installed my system about 2 yrs ago and have always had some pressure issues. I have 1800 series pop up Rainbirds for the majority of my lawn, and a large area of my yard has rotors. The pop ups barely have enough pressure to extend fully and the rotors have a weak stream needless to say my coverage is not very good and I have to water twice as long to keep my lawn alive.

I laid out my yard and had a local plumber lay out the sprinkler system for me. They said they design them around 40 psi and I tested my secondary water at the street and it was about 50 psi. I have 1" line with five zones. The pop up zones were designed with about 16 - 12' half pattern spray heads and the one rotor zone has 6 rotors on it. I can't figure out why my pressure is so low. Any help would be greatly appreciated.

Justin

mrfixit

Moderator

Posts: 1,510

Location: USA

2

Saturday, June 21st 2008, 10:47pm

low pressure

16 spray heads on a line is way too many in my opinion with 50 pounds. Even with 12 foot halves. I'm thinking 8 would have been a better choice with the low water pressure your system has. You have to ask yourself how many sprinkler systems has that plumber designed? One perhaps. -- Maybe someone will crunch the numbers for you. HKD's good at that.
If I can't fix it, it's broken!

atkinson4738

Unregistered

3

Saturday, June 21st 2008, 10:54pm

That is kind of what I was thinking which is why I included that info. The funny thing is this is probably the biggest plumbing shop in the state and practically everyone who does there own system in the area goes through this process of having them design it for them. The guy who designed it has been doing it for years and it seems strange he would screw up like this.

Wet_Boots

Supreme Member

Posts: 4,102

Location: Metro NYC

4

Sunday, June 22nd 2008, 8:57am

  • "They" didn't screw up. Installing a system without first verifying the water supply is the screw-up.

atkinson4738

Unregistered

5

Sunday, June 22nd 2008, 10:10am

What do you mean by water supply? I did supply them with my psi (50) and they designed it around 40 psi, so I don't understand what you mean by "verifying my water supply".

mrfixit

Moderator

Posts: 1,510

Location: USA

6

Sunday, June 22nd 2008, 3:11pm

supply

In order to design a system and how many heads to use you need to know the water pressure and the flow rate, gpm. Also pressure lose due to many variables. You can get 50 pds of pressure thru a pin hole. You did say you had 1 inch line though. So "they" did screw up by designing a system without all the information needed. I might be wrong but it sounds like Boots is insuating it's your fault. I say you trusted and paid a professional based on reputation to know what he's doing. I don't do installations anymore. I haven't installed a system for 13 years. I'm strictly repairs. I can tell you I've worked on many many systems with 50 pds and not one of them could run 16 twelve foot half spray heads let alone 40 pds the system was supposedly designed for.
If I can't fix it, it's broken!

Wet_Boots

Supreme Member

Posts: 4,102

Location: Metro NYC

7

Sunday, June 22nd 2008, 4:44pm

If you aren't paying someone to do actual flow testing, or doing it yourself, you are getting a pig in a poke when you have a design done on the basis of a pressure reading alone. Things may work out most of the time, but someone has to be the unlucky exception. Only by measuring flow and pressure together, can you have an accurate picture of the water supply. Working without that accurate picture is a mistake. Assign the blame wherever you wish, but it was still a mistake. Since a one inch water meter (is it a one-inch meter?) can handle a 50 gpm flow, you'd think you could manage 15 gpm, but that isn't always going to be the case.

mrfixit

Moderator

Posts: 1,510

Location: USA

8

Sunday, June 22nd 2008, 7:45pm

Plumber

So we basically agree. The design shouldn't have been made based on water pressure alone. Here in California, plumbers aren't allowed by law to design a sprinkler system. Landscape contractors aren't even allowed to draw up plans for the yards they install. You need a landscape architect license which is a 4 year degree.
If I can't fix it, it's broken!

atkinson4738

Unregistered

9

Sunday, June 22nd 2008, 9:39pm

I think that is the exact point mrfixit. I have installed about five systems, but obviously I don't know the best way to design so I paid the professionals that claim they design them very well. Don't get me wrong though, I love the guys at the plumbing shop they are always extremely helpful and their prices are great, so the "blame" is not really that, it was just a statement of confusion on my part as to why they would have designed it this way.

Aside from this though is too many heads on a line the issue for sure? I was wondering if the main line may be kinked somewhere. I checked the pressure at the manifold and it is the same as it is at the meter (yes the meter is 1 inch). After I did this I kind of realized that really didn't tell me anything because even if the line is kinked it can still build up pressure, but once a valve opens having the pressure maintain would be the issue, correct?

Is there any troubleshooting steps to figure out if my main line may be kinked, or am I going to have to add valves and split the lines? Wetboots - you mention I should be able to handle 15 gpm at 50 psi, do you have any good resources on how I calculate the gpm and how it coorelates to psi?

hi.todd

Supreme Member

Posts: 417

Location: Houston, Texas

10

Sunday, June 22nd 2008, 10:58pm

After you do a flow test. See what you have to work with. Usually,the MP rotor that used to be walla walla sprinkler company and sold them to Hunter, can fix flow problems because they can run on 30 PSI and usually have a lower GPM than spray heads and rotors. You may want to convert the whole system. Open a hose bib at the house, close the meter and then open it. Sometimes meters take more than 360 degrees to open up all the way. You opened the hose bib so that you can watch and listen as you open and close your meter to understand when it is fully open. Your meter can be in need of repair or your line can be kinked. You will need to verify what it is you are working with flow wise.

Good Luck.

Dan :thumbsup:
:thumbup: :thumbsup:
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