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View Full Version : Attention!! please read! booster question.


skrats
05-05-2006, 10:19 PM
I need to carry 20 psi 1000' in 2" pvc. is this possible with the help of a booster pump?? i already have 20 psi at my source. in to have 30 at the end of 1000' feet of 2" pvc.

Dirty Water
05-05-2006, 10:22 PM
How many GPM?

skrats
05-05-2006, 10:29 PM
300 approx.

Wet_Boots
05-05-2006, 10:34 PM
No way in hell. Not even a glimmer of hope.

skrats
05-05-2006, 10:35 PM
i tapped into a 15" well at a dairy house. i was told i would have 55 psi to work with. i installed a 2" mainline along the road which is 1000' feet long. i have zones with 18 4" popups with the 15x15 nozzle. the problem is that i installed the system before i had water. its hooked up and the heads dont perform well at all. i need at least 20-25psi at the end of my line. Thank you sooo much for replying so soon

JeffY
05-05-2006, 10:35 PM
300 gpm....you'd need a 24" size line...if that's even possible. hopefully you meant 30

skrats
05-05-2006, 10:36 PM
no hope?? are their any options. What is the most psi i could boost at 1000'

skrats
05-05-2006, 10:37 PM
well they told my that they have a 15" well and they have many tributaries off of this so called source. now i have a 2'' pipe that i was to connect to right off the building.

Wet_Boots
05-05-2006, 10:40 PM
Thirty gpm is a more realistic flow for a long run of 2 inch.

Dirty Water
05-05-2006, 10:41 PM
300 gpm puts your water velocity at 27 ft per second. Which is waaay over the safety line.

300 GPM also means your going to lose 39 psi per 100 feet. I'm surprised your getting any water at all :D

Now your saying your getting 20 psi at the tap, but 300 gpm, I'm sure your 15" well has a crazy huge pump, and your just totally confused.

I hate to say it, but you've totally hosed yourself on this one. This is why people with experience should install irrigation. My first clue that someone doesn't know what they are doing is when they suggest a booster pump to fix a problem.

skrats
05-05-2006, 10:41 PM
they are allowing me to take away from their supply.... 75 gpm. so i constructed my system for that. the nozzles take 3.73 gpm and i have 18.
thats 67.14 gpm that im taking. i know that i am missing something major here.. i am totally stumped of what i need to solve this prob.

skrats
05-05-2006, 10:43 PM
so i need to reduce the amount of water that i am getting??

Dirty Water
05-05-2006, 10:46 PM
they are allowing me to take away from their supply.... 75 gpm. so i constructed my system for that. the nozzles take 3.73 gpm and i have 18.
thats 67.14 gpm that im taking. i know that i am missing something major here.. i am totally stumped of what i need to solve this prob.

If your just using 67 GPM, your going to lose around 30 psi at the end of the run. Why are you only getting 20 psi at your source?

I would have ran a 3" main with 2" zones.

skrats
05-05-2006, 10:47 PM
i have 1" zones

Wet_Boots
05-05-2006, 10:49 PM
Cut the zones in half, maybe. Throttle down 9 of the 18 15SQ nozzles, and see what you get.

skrats
05-05-2006, 10:52 PM
Is there any way to get the right amount of psi to the end without redoing the pipe?

Wet_Boots
05-05-2006, 10:53 PM
The only time I ever had near that amount of water in a one inch line, was when I was stuck with an existing under-walkway pipe. And I immediately branched off into three or four separate one inch pipes on the other side.

This is a good example of what can happen to someone who doesn't bother to read the hydraulic information in the back of most irrigation catalogs.

skrats
05-05-2006, 10:54 PM
if i take away four heads from the zone it performs ok. problem is... i would rather not redo the heads or the valves.. this would involve alot more time and money.

Wet_Boots
05-05-2006, 10:57 PM
Chalk it up to experience. Many beginners completely ignore the basic hydraulics of a sprinkler system. You just get to pay for the mistake on a larger scale than most folks do. I say cut the zones in half.

Do what it takes to get paid.

skrats
05-05-2006, 11:06 PM
There isnt a way to reduce the 300 gpm coming into my line to cut back on the psi loss?

skrats
05-05-2006, 11:07 PM
Dirty Water, whats your opinion?

Wet_Boots
05-05-2006, 11:08 PM
What 300 gpm? You turn on a zone that consumes 60-odd gpm. Where does the 300 gpm enter into it?

skrats
05-05-2006, 11:18 PM
it enters through a series of smaller 6 inch lines.

skrats
05-05-2006, 11:22 PM
i cant really see everything. all that i see is.. at one side of the building.. there is a psi box that reads 54psi digitally. this is where they told me i had that much psi. about 30' away there is a bunch of 6 and four inch pipes with my 2" line going outside.

Wet_Boots
05-05-2006, 11:26 PM
The water main my last sprinkler system was running from could carry 2400 gpm. Big deal. Since that main was feeding a house through a 3/4 supply line, all I could use was 10 gpm.

You really need to do some studying. Your grasp of the technical details of sprinkler systems is weak, at best.

You got any backflow prevention in this system?

skrats
05-05-2006, 11:28 PM
yes i do have a backflow preventer.

skrats
05-06-2006, 09:24 AM
please dont give up on me here guys. I am still unsure of the best solution for this problem.

DanaMac
05-06-2006, 09:48 AM
This happened once on a project I worked on about 12-14 years ago. Landscaper subbed out to the company I worked for at the time. We just installed the irrigation. And we were handed the plans from the architect, which were given to the landscaper. Designed with certain psi and gpm in mind. We didn't have the water source until about half way through the job. Zones barely worked. I think there were a few things we did.
1. the landscaper drastically reduced the grass areas and added more mulched and rock areas - eliminating heads
2. split many zones into two - using the spare wires, running new wires to the manifolds close to the controller, and even using Doublers to farthest valves
3. changed some zones from sprays to rotors with smaller nozzles, reducing nimber of heads

You're not going to find a quick easy solution for this - meet with the landscaper, architect, and whoever else is in charge, especially whoever told you what psi and gpm you had. Tell them this is the problem, it is resting on everyone's shoulders, not just yours, and you're all going to have to eat some of it.

PurpHaze
05-06-2006, 10:26 AM
i cant really see everything. all that i see is.. at one side of the building.. there is a psi box that reads 54psi digitally.

Is this static (no movement) pressure or dynamic (moving) pressure? I'm guessing it's static and pressure always drops when the water starts actually moving.

You always design a system to it's worse-case sprinkler scenario which in your case would probably be the last sprinkler in the last zone. If you design and build to this sprinkler and it works (PSI and GPM) then you are guaranteed that all sprinklers prior to this one will work properly.

You're undersized from the very beginning. To carry that 67 GPM your main line should have been a minimum of 2-1/2" and I'd have probably gone 3" which slows the water down even more and creates less friction which equals less pressure loss.

Cap off some sprinklers or split the zones.

PurpHaze
05-06-2006, 10:29 AM
so i need to reduce the amount of water that i am getting??

No... You need to reduce the amount of water you're actually using in each zone. You can do this by either capping off some sprinklers, splitting the zones or using a sprinkler that does does not use as much GPM per head.

PurpHaze
05-06-2006, 10:40 AM
if i take away four heads from the zone it performs ok. problem is... i would rather not redo the heads or the valves.. this would involve alot more time and money.

Each head is using 3.73 GPM. By "taking away" 4 heads you are reducing the total zone GPM by 14.92 GPM (3.73 x 4 = 14.92) to 52.22 GPM per zone. This amount is under approximately the 55 GPM that CL 200 PVC pipe will carry safely without creating friction and additional pressure loss.

You apparently have adequate pressure when the overall zone GPM is reduced.

You still have a problem by using 1" valves for a zone that should have had 2" valves and then been sized accordingly from there to the sprinklers.

PurpHaze
05-06-2006, 10:45 AM
300 gpm....you'd need a 24" size line...if that's even possible. hopefully you meant 30

Say what???? 6" CL 200 PVC pipe will carry 490 GPM and keep the flow under 5' per second.

skrats
05-06-2006, 06:06 PM
i have 1 1/2" valves but 1" lines.

skrats
05-06-2006, 06:10 PM
Im now thinking that we need to get a different source. What size well would i need to take care of what i have in the ground?

Dirty Water
05-06-2006, 06:17 PM
Im now thinking that we need to get a different source. What size well would i need to take care of what i have in the ground?

First off, forget about 300 gpm, I assumed you meant you were using that much water, You are really using 67 GPM.

You have two problems here:


You cannot move 67 GPM through a 1" line and keep water velocity at a safe speed, and pressure loss acceptable.

You are moving 67 GPM through a 2" line, which means that by 1000' you will have lost a enormous amount of pressure.


Even if you did have high pressure at the source, your are moving too much water through your zones.

Either your zones should be smaller, or the pipes should be larger. No amount of pressure boosting is going to fix this safely.

The proper setup for this would have been a 3" main line with 2" valves, and 2" ran to at least the first 4 or so heads, and then step down a pipe size, run to the next few heads, and so on, so that your last head would be ran off 3/4".

The only solution in your situation is to split the zones up, or change to heads that use less GPM (MP-Rotators will fit on your spray popups and may solve your problem, they use much less GPM and don't require much pressure to operate)

Your stuck with the 2" mainline, so focus on the zones. Start on the farthest zone. If you can get this one to work well, you'll be able to get the rest.

Wet_Boots
05-06-2006, 06:25 PM
Why can't you just split your zones in half? If you have one inch zone lines, then nine sprays is about as much as they'll handle. How many zones are there now? Any reason you can't just pull out the inch-and-a-half valves, in favor of one inch valves? If you can get the additional work down to some new valves, wire, and one inch pipe, along with whatever controller upgrade is needed, I'd say you're getting off easy.

The system as you installed it will not function. You will have to rework it. You will not look at other options.

skrats
05-06-2006, 09:07 PM
I am going to focus on splitting the zones in half. But would a pressure booster work if had one at the beginning and then another towards the end??

Dirty Water
05-06-2006, 09:27 PM
I am going to focus on splitting the zones in half. But would a pressure booster work if had one at the beginning and then another towards the end??

NO!

Though, If you loop your main you will cut your flow loss in half in the mainline. Solving problem #2 in my above post.

However, your still pushing 67 GPM through 1", which means your zones will never perform well.

Wet_Boots
05-07-2006, 10:30 AM
The system as you installed it will not function. You will have to rework it. You will not look at other options.

Repeat that mantra as necessary. The idea is to present an install that will function, and not present the purchaser with an opportunity to complain. If I were buying a job, I would take a very dim view of someone trying to inform me that I had to spend additional booster-pump electricity to make the sprinklers run.

Get it right, and get paid. Get it wrong, and get grief.

Dirty Water
05-07-2006, 11:07 AM
To further elaborate on Boots:

This is nobodies fault but yours!

You are the one that chose those pipe sizes and zone sizes. They are sized completely wrong, regardless of how much pressure you have. I could have designed a system that worked flawlessly off the available pressure, so don't go blaming it on the water people.

Chalk this one up to a learning experience. Study up on hydraulics and perhaps ask design questions here before you try another one.