Help me size my CSV/Pump/Motor

[IGR]

I realize this may be trivial here but it seems every supply house I ask about a CSV, look at me like a deer in headlights.

I just installed a 2800g cistern fed by our well. The system will be for filling five 1000gallon stock tanks, arena dust control and supplying a few drip irrigated garden plots.

Pump sits 9' below grade and all piping is 1.25" poly trenched 3ft below grade. Tank and manifold will be located in a 4'x4' concrete pit at the same level as piping. Runs are pretty much straight shots. Longest one about 300' with 3-4 elbows. All points of usage except sprinklers will be through Woodward Y1 frost free Hydrants with 1" inlets and 3/4" hose outlets. (I'm told they flow 28gpm @ 50psi)

Zones:
1) Arena: 120'x220' covered by two Sime K1 sprinklers. (http://bigsprinkler.com/products/sime-k1-sprinkler) Roughly 25gpm @ 50psi will do the trick if I use one sprinkler at a time. 36gpm @ 44psi does the job slower but running both would be very convenient. 

2)Stock tanks: 1000 gallons each. I let them run low, drain, clean and refill at one time. They are not on float valves. (Faster the fill time the better)

3)Drip Irrigation: This years plot will only require 16gpm @ 12-15psi. Each irrigation time is expected to be 1.5-2hrs. Future plots will mimic this one in regards to demand. I expect at least one more plot so demand would double if I wanted to irrigate both at once. Although, being split into zones and different crops. I dont see a need to irrigate both at the same time.

4) A single hydrant will be available for general usage. (washing horses, cleaning things etc)

When looking at 35gpm Franklin E series and 4" high capacity pumps coupled to 1.5hp motors it appears they sit nicely in the efficiency range around 30gpm @ 50psi however I'm not sure if I'm calculating head correctly or for the CSV? I'm confused considering the CSV derating the motor and if I should go with a higher/lower hp motor.

Here is a link to franklin/schaefer pump charts: http://www.franklin-electric.com/media/documents/MS2009_Schaefer_Catalog_04-14_WEB.pdf

I would really appreciate help in correctly selecting a motor/pump in conjunction with the CSV for my application. I'm very familiar with VFD's in other industries but think its overkill and an unnecessary level of complexity for this systems usage. But hey, if I need one, I need one.

Thank you in advance for any help.

[Cary Austin]

We have been using CSV’s to solve these kinds of problems for 22 years now.  If the supply houses haven’t heard about them, they are not very well educated on pump systems.  More than likely they have heard about CSV’s, and their companies have chosen to act like they don’t know what it is, or to claim CSV’s don’t work for some reason.

Can’t say as I blame them.  A CSV125-50 will only cost you $111.30, and you would only need about a 20 gallon size pressure tank, which I see selling for $140 or so.  So for roughly $250, you will have every thing you need to run from as little as 3 GPM up to 35 GPM, as that is the amount that pump can produce.  The CSV will make your pump, tank, switches, and everything else in your pump system last many decades.

The CSV was designed as a simple, inexpensive, and long lasting replacement for VFD’s, and we have replaced hundreds of thousands of them in the last 22 years.  The supply houses would rather you purchase a couple of really large pressure tanks for about $2,000.00.  Or they would be fine selling you a VFD for a couple thousand as well.  Either of these will make the supply houses a lot of money.  Neither of these will last very long or make your pump last very long, so they will get to sell you a new set up on average of about every 7 years.

It has been proven that a CSV will at least triple if not quadruple the life of pumps and associated equipment.  So if you want the supply houses and pump manufacturers to make a lot of money off of you, go with the VFD or a couple of large pressure tanks.  If you want something inexpensive that will last a long time, you have come to the right place.

I looked up the pump curve you posted and the 35 GPM, 1.5 HP pump will work fine with our plastic, domestic grade CSV125-50 for $111.30.  Or you can use one of our heavy-duty, long lasting, municipal grade CSV3B2T valves, which sell for $647.50.  You won’t see any difference in performance between these two valves.  Just that one is adjustable and longer lasting than the other.  However, for the difference in price, you could replace the CSV125-50 about 6 times for the same money as the CSV3B2T if needed.

I have had one of the little plastic valves in my well for 22 years now.  But water quality has a big effect on how long these valves will last.  If you have dirty or slimy water, the more expensive CSV3B2T would be best.

There are lots of good applications for VFD’s.  But pumping water like this is not one of them.  VFD’s are just used for these kinds of water pumps because the company that sells the pumps and VFD’s will make a lot more money.  If you don’t mind paying a lot more and having a lot more problems, then a VFD is what you want.

Oh, BTW, Franklin is one of the biggest instigators of pushing those VFD's on people.  So I would prefer to see you use a different pump company and not encourage Franklin.  F&W is a good US made pump, and now they have their own motor.  I had just rather promote companies who are not trying to shove a VFD down peoples throats for the extra profit.

[IGR]

Thank you for the prompt response. Due to my plans for mounting the tank,csv and pressure switch in a 4'x4' below grade insulated service pit I was concerned about the plastic valves weeping and additional moisture build up being an issue for the switch. I do have about a foot of sand in the pit but feel it would be better not to introduce additional moisture.

Would a CSV2W be a suitable replacement for the plastic valves you mentioned? I realize the minimum tank fill rate will be higher at 5gpm and I have not yet checked dimensions but I was thinking I could theoretically use a tank with a 5-10 gallon draw down and still maintain decent pump run times when using water for short periods. Is there something else I'm missing?

Also, what quality tank brands do you recommend?

[IGR]

Another question I forgot to ask was regarding the time spent drip irrigating. By far, the most frequent condition the pump will see will be the 16gpm @ 12psi during growing season. This equates to a few hours run time 2-3times per week. Is this 30+gpm 1.5hp setup going to be too overkill and inefficient?

[Cary Austin]

The reason I didn't mention the CSV2W was because it has more friction loss which won't work with that 1.5 HP pump.  You would have to go with the 2 HP to get the same water if you use the CSV2W.  The CSV125 and the CSV3B2T have much less friction loss than the CSV2W.

I prefer Well-X-Trol tanks but, the brand is not as important with a CSV as the bladder in the tank will see much less cycling.

The smaller the pump the more efficient it will be with the drip system.  Or you can double up on the drip and run 2 of those 16 GPM zones at the same time.

[IGR]

I just realized with our cisterns refill rate I only have capacity to irrigate one drip plot at a time either way. I'm thinking adding two valves and a controller to the arena sprinklers is a better solution than compromising efficiency 90% of the time.

Would downsizing to a 25gpm pump and 1 or 1.5hp motor allow me to run the CSV1A?  I'll want at least 25gpm @ 50psi from the hydrants. Will that combo be good for it?

Thanks again for all the help.

[Cary Austin]

The CSV1A can get you 25 GPM at 50 PSI with a 25 GPM, 1.5 HP pump.  You will need to set the CSV1A at 65 PSI while running 3 GPM to get 50 PSI at 25 GPM because of the reduced pressure falloff on that valve.  CSV set at 65 means the pressure switch needs to be about 50/70.

You can do the same thing with a 1HP, 25 GPM pump using the CSV1-50 as it has very little friction loss and no reduced pressure falloff.

[IGR]

Please bare with me here..

It looks like sticking a plastic CSV in the cistern, submerged, after the check valve, would solve these issue as it seems I'm stuck in the middle of two options neither of which are without compromise.

The literature regarding the plastic valves say they are not suggested to be used in water with algae/dirt. The well does produce some visual silt occasionally(which may clear the more we use it) and the concrete cistern will certainly have algae growing in it yet you recommended it for this application?

What problems exactly do these conditions promote? Does mounting it submerged negate these concerns? What might I see for life expectancy?

[Cary Austin]

The plastic CSV’s are my favorite.  That is what I use at my house.  They have almost no friction loss and no reduced pressure falloff.  So they give you more water from the pump than our other valves, and hold a constant pressure throughout the 1 to 25 GPM range.

The design of this valve, which reduces losses so well, is also the reason that these valves can leak a little through the air vents.  The valves only leak when there are abrasives or slimy stuff in the water, and then they usually only leak about 1 gallon per week.  As long as the valve is installed inside the well casing or inside the cistern, who cares if it leaks a gallon a week?  The CSV1 does not have to be submerged, but installed inside the cistern tank either way does negate most of the problems with this valve.  That little leak can only be a problem if the valve is installed where it can make a wet spot on the floor.

As long as the plastic CSV’s can vent, they will work.  So if you have something slimy in the water, we have instructions on how to drill a larger vent hole to keep the slimy stuff from clogging up the air vent.  See this link.  http://www.cyclestopvalves.com/prod_csv1_submerged.html

The 1” plastic CSV’s are only 63 bucks.  So you really can’t afford not to use one.  And when used with a small pressure tank they save hundreds on equipment costs.

You will want to add a little chlorine occasionally to keep the growth out of the cistern tank.  With any system that has a water quality issue that can affect the CSV, pressure tank, pressure switch, check valves, etc., I recommend a Cycle Sensor for protection.  See this link.  http://www.cyclestopvalves.com/prod_sensor.html

The Cycle Sensor will shut the pump down if the CSV, pressure tank, or pressure switch malfunction and lets the pump start cycling too fast.  It will also shut the pump off if you pump the cistern dry.  Both of these things can save the pump/motor if something does get clogged up.

[IGR]

Cary, I'm awaiting quotes for the pump etc and I think I'm going to try to swing the money for a CSV3B2T.

Just wanted to double check our phone discussion:

Pump to hydrant outlet: 12'
Friction loss(pump to outlet): 36' @ 30gpm (300' 1.25" poly)
Desired pressure @ outlet: 50psi/115' (or should I fudge this to 60psi?)

12+36+115= 163' or 55psi total

Pressure switch (50psi @ outlet):
Friction loss: 10psi over 300'

50psi cut in with 70psi cut out = 60psi average at switch = 50psi average at outlet

Thanks again. You have been tremendously helpful.

[Cary Austin]

Your 163' is correct, but divided by 2.31 makes that equal 70 PSI not 55.

So you need the CSV set for 70 PSI with a 60/80 pressure switch, then you are good to go.  The 70 PSI is why you will need a CSV3B2T.

[IGR]

10-4 couldn't get my head around how that stacked up.

Thanks again.