Reworking my well - options on sprinkler side

[k-n]

I am going to completely redo my well system. Currently I have a 3HP electric that can pull quite a bit of water out of the ground. I have a 1500 gallon storage tank. I have a goulds J10 1HP electric pump. I also have a higher end whole house pre, carbon, and post filtration system with a chlorine injector. My well house is big enough to expand inside. Here is what I'd like to do:

trench a second line from the well house to house for a sprinkler line. The sprinkler line will come off of the return line from the well tank and bypass the filtration system as it is not needed and wasteful. My question is, given the amount of draw from a sprinkler, would it be possible to use another goulds J10 or something similar that cuts on when sprinkler demand is present and cuts off when it is not so that I don't have to spend the money on another pressure tank? What's the best way to do this?

 

[VAWellDriller]

Short answer yes....if I'm reading you right you
1) predict a higher demand when irrigating than the current pump can handle; AND
2) want the irrigation water to bypass the filtration?

The current order of equipment should be 3HP from well to storage tank, Goulds J10, pressure tank with controls, filtration, then house?

If that is the case you could install a bigger pump in place of the J10 that would handle both needs, and tee the irrigation off between the tank and the filters; and install a cycle stop valve on the J10 discharge to keep if from cycling at low demand.

OR

Add another pump like you have asked. This is done all the time, would be called a Lead/lag setup (its done all the time on bigger systems). In that case you CAN do it with 1 pressure tank, but would need to have 2 pressure switches installed on the tank (and not use the switch that comes mounted on the pump). You would have the lead pump for example set up as normal with a 40/60 switch setting. The lag pump should be set up with a slightly lower switch setting, like 35/55. The lag pump should have a cycle stop valve installed right on its discharge and be set slightly lower than the lag pump cut out pressure setting. You could do this with a CSV on both pumps if you wanted to have constant pressure at both low and high volume situations, but it will take a lot more tinkering to get it set up right.

BY FAR the easiest solution would be to install 1 larger pump that would handle everything and install a CSV.

 

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[Valveman]

Like VA says! But your existing J10S will do 16 GPM at 50 PSI. This would let you irrigate at 11 GPM and still have 5 GPM for the house. If you want to irrigate with more than 11 GPM a larger or additional pump would be needed as VA says. But most of the time the problem is you won't even use 11 GPM for irrigation and the pump is cycling on/off because it is too large. The CSV will stop the cycling and make the pump do whatever you want it to do.

 

[LLigetfa]

If that is the case you could install a bigger pump in place of the J10 that would handle both needs, and tee the irrigation off between the tank and the filters; and install a cycle stop valve on the J10 discharge to keep if from cycling at low demand...

Keep in mind that fast acting solenoid valves on the irrigation system can generate water hammer that unsettles the media pack in filtration systems causing them to not filter as well.

 

[k-n]

Excellent! Thank you for the detailed notes. I'll look at the CSV route with the single J10S as I already have all that equipment sitting here and ready to roll. Just a bit of electrical work and the CSV along with some plumbing and it looks like I'd be good to go.

But... Just to be sure I understand... I will split the output from my goulds with one side of the T going to the filtration system and then to the house and the other side will feed the sprinkler. That way I'm not filtering the water I put on my grass. Of course it will smell like rotten eggs while I'm watering but it goes away quickly.

The CSV will then force my goulds to increase/decrease output as it is demanded downstream (up to 16GPM). Out of curiosity I assume the CSV adjusts the voltage to speed up/slow down the motor. Is this hard on the electrical windings in the motor to undervolt?

 

[LLigetfa]

Out of curiosity I assume the CSV adjusts the voltage to speed up/slow down the motor. Is this hard on the electrical windings in the motor to undervolt?

No, it does not change the voltage or the RPM.

 

[Valveman]

The CSV will then force my goulds to increase/decrease output as it is demanded downstream (up to 16GPM). Out of curiosity I assume the CSV adjusts the voltage to speed up/slow down the motor. Is this hard on the electrical windings in the motor to undervolt?

Like LL says the CSV doesn't affect the volts or hertz of the power to the motor. However, the CSV does affect the amperage. Amperage drop at full voltage with full fan speed is good for the motor, makes it produce less heat and run cooler. That is just the normal way pumps work. It is counter intuitive because our brains tell us restricting a pump with a valve should make it work harder. Whoever invented the centrifugal impeller was a genius because they only draw as much power as needed to supply the flow being used, even when running at full speed all the time. Most people think you need to vary the pump speed to get the amps to reduce, and the variable speed sales people just keep their mouths shut, let people believe this myth, and laugh all the way to the bank.