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View Full Version : Are rotors ok at 30 psi?


soafone
08-10-2012, 04:22 AM
Do rotors perform well enough at 30 psi? My volume is 12 gpm. I am drawing from 1" indoor plumbing connected to a well. The pump is in the well. I am worried that by the time i run out to the heads I will only be at 25 psi. What are my options to increase pressure while maintaining my volume?
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cgaengineer
08-10-2012, 06:31 AM
Do rotors perform well enough at 30 psi? My volume is 12 gpm. I am drawing from 1" indoor plumbing connected to a well. The pump is in the well. I am worried that by the time i run out to the heads I will only be at 25 psi. What are my options to increase pressure while maintaining my volume?
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A booster pump would keep your pressure up.
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Duekster
08-10-2012, 06:37 AM
You gotta have PSI to throw the water. Check the nozzle tree for the make and model.

soafone
08-10-2012, 07:13 AM
A booster pump would keep your pressure up.
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What is the cost of a booster pump? If I add say 20 psi to bring the pressure up to 50 psi, will I still be at 12 gpm?
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cgaengineer
08-10-2012, 07:24 AM
A booster pump is about $150. It will bring your pressure up, gpm is dependent on well pump so that would remain the same.. Booster will go on irrigation side.
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Duekster
08-10-2012, 07:26 AM
Also do not design to 12 GPM, desighn to 9 or 10 GPM max

cgaengineer
08-10-2012, 07:27 AM
https://m.northerntool.com/northerntool/product/detail.do?itemId=109258&categoryId=&path=&productName=false
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cgaengineer
08-10-2012, 07:28 AM
Also do not design to 12 GPM, desighn to 9 or 10 GPM max

Exactly...or a slight fluctuation (shower, toilet flushing or other demand) will decrease your pressure and spray patterns.
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Duekster
08-10-2012, 08:21 AM
Still need to know how big an area he wants watered. I would not put an irrigation system on a well I used for drinking water unless I knew I was not going to run the well dry. What is the recharge rate of the well and how much area is to be watered. Type of grass and so forth.

soafone
08-10-2012, 11:07 AM
The well production rate is 40 gpm. If I do not go with a booster pump, will the heads be ok with 30 psi static pressure at the source? Also, when you say design the zones at 10 gpm max, is that regardless of whether I use a booster pump or not?

Wet_Boots
08-10-2012, 11:33 AM
How many acres are you watering?

soafone
08-10-2012, 11:55 AM
I think it is an acre and a half.

Wet_Boots
08-10-2012, 12:38 PM
Simply put, if you want maximum coverage from a low pressure water supply, you will use heads with the most ability to function effectively at low pressure. Until further advancements, those heads are Maxipaw impact heads.

However, if you do have a 40 gpm well, you should consider a new pump to replace what you have now. Something that will give you 20 gpm at 70 psi would be about right for wide-open spaces where you'd like long throws.

Mike Leary
08-10-2012, 02:54 PM
Depending on the pump-down test/recharge rate, that sounds like a well to kill for. With the right pump, you could chuck some serious water. Re-charge is the name of the game.

jvanvliet
08-10-2012, 04:24 PM
Simply put, if you want maximum coverage from a low pressure water supply, you will use heads with the most ability to function effectively at low pressure. Until further advancements, those heads are Maxipaw impact heads.

However, if you do have a 40 gpm well, you should consider a new pump to replace what you have now. Something that will give you 20 gpm at 70 psi would be about right for wide-open spaces where you'd like long throws.

Use a centrifugal pump to make sure you get enough flow to feed your rotors; It's way cheaper than a submersible and produces loads more water than the much touted jet pumps.

Wet_Boots
08-10-2012, 05:52 PM
Use a centrifugal pump to make sure you get enough flow to feed your rotors; It's way cheaper than a submersible and produces loads more water than the much touted jet pumps.dude's in Canada, man

soafone
08-10-2012, 09:55 PM
I still would like to know if anyone can answer the million dollar question. "Do rotors work well enough at 30 psi?" My distributor tells me they do, but I am reluctant to believe him. I suppose I could ask the home owner to change the pump in the well, but I am sure he won't be anxious to do it, since he just took possession of the brand new home. So, I have three options...

1) run the rotors at 30 psi less the friction loss (end up with approx 25 psi at the rotors)
2) use a booster pump to add psi, yet the flow will remain at 12 gpm
3) ask the home owner to replace the pump.

I think option three is the clear winner. Fortunately for me, my estimate read that it was based on the home owner providing a 1" water supply capable of 12 gpm's @ min 50 psi.

Wet_Boots
08-10-2012, 10:12 PM
No professional worthy of the name installs gear-drive rotors running at 30 psi.

Is that clear enough for you?

Waterlogged
08-10-2012, 11:13 PM
I would think you would loose more then just 5 psi, no backflow ? How long is the line from the pump ? how long is the main ? what valve ? I'm thinking you will have less then 25 at the head and no it will not work.

soafone
08-11-2012, 12:25 AM
Short of replacing the pump, I think I have come up with a solution! Can I not just change out the pressure switch? When I did a gpm test, the pressure was at 30 psi, which leads me to believe the pressure switch is 30/50. I could swap it out with one that is 40/60 or even a higher one line 50/70 if available. Does this make sense? Would I still have 12 gpm's of flow, of would that decrease if the pressure is increased by the new pressure switch?

Wet_Boots
08-11-2012, 12:42 AM
Short of replacing the pump, I think I have come up with a solution! Can I not just change out the pressure switch? When I did a gpm test, the pressure was at 30 psi, which leads me to believe the pressure switch is 30/50. I could swap it out with one that is 40/60 or even a higher one line 50/70 if available. Does this make sense? Would I still have 12 gpm's of flow, of would that decrease if the pressure is increased by the new pressure switch?Uhhh, that is more a confession of incompetence. You don't evaluate a pump while it is cycling on and off.

Besides, you adjust a pressure switch, rather than swap it out.

AI Inc
08-11-2012, 07:37 AM
I still would like to know if anyone can answer the million dollar question. "Do rotors work well enough at 30 psi?" My distributor tells me they do, but I am reluctant to believe him. I suppose I could ask the home owner to change the pump in the well, but I am sure he won't be anxious to do it, since he just took possession of the brand new home. So, I have three options...

1) run the rotors at 30 psi less the friction loss (end up with approx 25 psi at the rotors)
2) use a booster pump to add psi, yet the flow will remain at 12 gpm
3) ask the home owner to replace the pump.

I think option three is the clear winner. Fortunately for me, my estimate read that it was based on the home owner providing a 1" water supply capable of 12 gpm's @ min 50 psi.

why dont you just turn up the pressure? Remember to increase the air pressure in the tank too.

muddywater
08-11-2012, 09:47 AM
And use a cycle stop valve. And isually you can adjust pressure switch.

I try to get a well company to evaluate the well. You will prob be the only contractor that will suggest it. And you are covering the homeowners butt as well as yours.

Last job i got the well company to do that, i was the only contractor that suggested it and they wouldnt even look at other bids. 12k job that was very profitable. And Mike i used stainless i20s and sch 40! Mike oleary special!

You HAVE to know the recharge rate! At least call the well co, the installer may already have records on file.
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grassman177
08-11-2012, 11:58 AM
i have never done any work with a pressure switch, or a lake/pond or well. however, i think i would be able to figure it all out just fine. there is simply not any of those used around here, except one job i know of, and i dont have them as a customer