Irrigation well surging

[Shallowellconfusion]

Hoping I can find some help in these forums. My house has a shallow well (about 25 feet deep) that can be used for irrigation, but the house is on city water. It appears that when the house was flipped before we bought it that the flippers gave up on using the well for the sprinkler system and just cut city water into the system. I’ve been trying to get the sprinklers to work on the well for the last few years with minimal success. Stations near the well work, but anything further away won’t even pop the heads up.

In an effort to solve this, this year I bought a 1.5hp submersible well pump along with a 20gal pressure tank and have installed it. The well is sitting very close to the bottom of the well, has a check valve right after the pump, then comes up to the pressure tank and to then to the sprinkler supply line. I have a 40/60 pressure switch at the tank that is then wired into the pump control box that is then connected to the pump.

The sprinklers now all seem to work well until the pressure tank empties. Then as the pump runs I get “surging” from the pump. If the pump is running at the top of the surge the sprinklers run but not otherwise. I’ve checked the pressure tank and the pressure is set to 38. The pressure switch seems to be working correctly.

What could be causing this? I’ve been wondering if the well is pumping too fast and pulling bellow the well intake, but the surges are quick and there doesn’t seem to be any air getting in the system. Any help would be appreciated! Happy to provide more information!

 

[Valveman]

Surging or cycling on and off?

 

[Shallowellconfusion]

Surging or cycling on and off?

Surging not cycling. Pressure switch stays on but pressure surges by about 20psi. Continues doing that tell the sprinkler is turned off and pressure can build in the tank again.

 

[Valveman]

Check amps on motor. If amps are surging the same way you are pumping the well down. Use fewer sprinklers per zone.

 

[Shallowellconfusion]

Check amps on motor. If amps are surging the same way you are pumping the well down. Use fewer sprinklers per zone.

Thank you. I did test the motor yesterday with multimeter but did volts and am now realizing amps is probably better.

I’ve been thinking that the number of sprinklers is an issue. My theory is that when they switched over to city water they cut in a new sprinkler system with no regards to the well. Is the surging happening just because there’s more outlets for the water than the pump can supply but there’s resistance in the 1” supply line as it pushes? Thus it seems like pressure is going up but as soon as the pump slows it’s gone? Am I thinking about that right?

 

[Valveman]

I can tell the well/pump is making water. Just not as much as the sprinklers are using. I would try cutting the number of sprinklers in half and try again. You can actually test the well this way. How many sprinklers can the well make? But if you are using a pump start relay the pressure may increase too high to cut the number of sprinklers. If you are using a pressure tank/pressure switch instead, cutting the number of sprinklers can cause the pump to cycle itself to death. A Cycle Stop Valve will control the pressure when working with a pump start relay and will eliminate the cycling when working with a pressure tank and switch.

https://cyclestopvalves.com/collections/pump-control-valves/products/csv1a

 

[RS]

You bought way too big a pump!

 

[Shallowellconfusion]

You bought way too big a pump!

This is complete possible! I went from a 26gpm pump to a 37! My problem is that it was going to cost me significantly more to hire a professional to help than it was to just guess, purchase a pump and install myself. And my sprinkling system is all over the place in terms of small stations and then large ones.

One question I have though is that if the pump is too big how come it doesn’t fill the pressure tank when it start surging? I would have thought the risk of a big pump would be that if cycles quickly because it’s quickly dimming the pressure tank and that it would over push the sprinklers.

 

[Shallowellconfusion]

I can tell the well/pump is making water. Just not as much as the sprinklers are using. I would try cutting the number of sprinklers in half and try again. You can actually test the well this way. How many sprinklers can the well make? But if you are using a pump start relay the pressure may increase too high to cut the number of sprinklers. If you are using a pressure tank/pressure switch instead, cutting the number of sprinklers can cause the pump to cycle itself to death. A Cycle Stop Valve will control the pressure when working with a pump start relay and will eliminate the cycling when working with a pressure tank and switch.

https://cyclestopvalves.com/collections/pump-control-valves/products/csv1a

Thank you. I think my next step is to confirm the amps and then rework the sprinkling system (ugh) to use less and lower flow heads. I may also add a second pressure tank as I think 20 gal is small for my application but the biggest I could fit hight wise.

 

[RS]

You don't need another pressure tank, many sprinkler systems run without one if the zones are sized to the pump. Can you find out if the well ever did supply more water, maybe it just needs cleaning. It's possible to put an acid treatment in a well, let it work for a while, then blow it out with a large air compressor. Then maybe the well will provide enough water for the large pump you already have, otherwise you could put an orifice in the line from the pump to the pressure tank to reduce the amount of water it's actually pumping.

 

[Valveman]

Thank you. I think my next step is to confirm the amps and then rework the sprinkling system (ugh) to use less and lower flow heads. I may also add a second pressure tank as I think 20 gal is small for my application but the biggest I could fit hight wise.

Maybe you didn't hear me? Get a Cycle Stop Valve! ALL pumps are "too big". They have to be large enough to supply peak or max demands, but rarely are max demands used. When using anything less than max volume the pump can produce it will fill the tank and shut off. Then because the sprinklers are still running, it will quickly drain the tank and come back on. (CYCLING OVER AND OVER UNTIL PUMP DEATH)

A 20 gallon pressure tank only holds 5 gallons of water. To get the 60 second minimum run time a 37 GPM pump needs it would 8 of those tanks ganged together, or a couple of huge 80 gallon tanks. That is just for 1 minute of run time. You can't put enough tanks on a system to keep the pump from cycling when using less than max pump flow.

An "orifice" to restrict pump flow to match the zones is a good idea. But as you said, "zones are all over the place, from small to large", and they usually are. The Cycle Stop Valve is a variable orifice. The CSV restricts the flow to match the zone, no matter if it is a small or large zone. The 20 gallon tank is way bigger than needed when used with a Cycle Stop Valve, you just need the Cycle Stop Valve.

All pumps work on a curve. They pump a lot of water in a shallow well and less water in deeper wells. The only reason that pump can make 37 GPM is because the well is shallow. The same pump would only be able to produce 1 GPM in a really deep well. The Cycle Stop Valve just makes the pump think the well is deeper when a smaller zone is being used. Pumps less than 2HP only need to produce 1 GPM to stay cool, and can run at 1 GPM continuously without any problem.

I am concerned that going from a 26 to a 37 GPM pump it may not even make enough pressure to shut off at 60 with a 40/60 switch. Give me a model number of the pump and I will look it up. Remember that curve. Higher volume pumps make less pressure.

 

[MicEd69]

Remember that curve. Higher volume pumps make less pressure.

And the higher volume pumps use more power. The CSV restricts the flow, thereby increasing the pressure as the curve shows, and reduces the power draw to match the flow rate the pump is making. The varying flow of water from the pump allows a continuous and varying flow of electrical power to the pump rather than the "inrush" power required to start the pump when operated strictly on a pressure switch, on and off mode.

 

[Valveman]

Thanks MicEd, and sorry to be so short this morning. Just when someone tells me "Thanks for the explanation", then also says "They need an extra pressure tank", I want to beat my head against the wall for not having explained the CSV well enough. Here is a typical pump curve for a 25 GPM, 1HP pump. You can see that it will pump 34 GPM if the water in the well is only 80' deep. The same pump can only pump 1 GPM if the water level is 210' deep. The CSV will keep the pressure on the house and/or sprinklers at a strong constant 50 PSI while making the pump think the well is between 115' deep and 210' deep, depending on how much water is being used.

Also notice the horsepower curve is at 1.4HP when pumping 34 GPM, but only at 0.4HP when pumping 1 GPM. So, which do you think is easier on the pump/motor? 1.4HP is like running at red line all the time, while 0.4HP is almost like coasting down hill.

 

[Shallowellconfusion]

Maybe you didn't hear me? Get a Cycle Stop Valve! ALL pumps are "too big". They have to be large enough to supply peak or max demands, but rarely are max demands used. When using anything less than max volume the pump can produce it will fill the tank and shut off. Then because the sprinklers are still running, it will quickly drain the tank and come back on. (CYCLING OVER AND OVER UNTIL PUMP DEATH)

A 20 gallon pressure tank only holds 5 gallons of water. To get the 60 second minimum run time a 37 GPM pump needs it would 8 of those tanks ganged together, or a couple of huge 80 gallon tanks. That is just for 1 minute of run time. You can't put enough tanks on a system to keep the pump from cycling when using less than max pump flow.

An "orifice" to restrict pump flow to match the zones is a good idea. But as you said, "zones are all over the place, from small to large", and they usually are. The Cycle Stop Valve is a variable orifice. The CSV restricts the flow to match the zone, no matter if it is a small or large zone. The 20 gallon tank is way bigger than needed when used with a Cycle Stop Valve, you just need the Cycle Stop Valve.

All pumps work on a curve. They pump a lot of water in a shallow well and less water in deeper wells. The only reason that pump can make 37 GPM is because the well is shallow. The same pump would only be able to produce 1 GPM in a really deep well. The Cycle Stop Valve just makes the pump think the well is deeper when a smaller zone is being used. Pumps less than 2HP only need to produce 1 GPM to stay cool, and can run at 1 GPM continuously without any problem.

I am concerned that going from a 26 to a 37 GPM pump it may not even make enough pressure to shut off at 60 with a 40/60 switch. Give me a model number of the pump and I will look it up. Remember that curve. Higher volume pumps make less pressure.

View attachment 46647

I mean… ugh maybe I’ll get a CSV! I should have rephrased the above to ask what I really mean which is “that’s a $250 valve and a pressure tank is half that price, would that help before I spend the money?” Thanks for the explanations to help me understand this. Seems like no matter what I do here, short of reworking the whole sprinkler system to have the same load on each station, the CSV is the only thing that will help.

 

[Shallowellconfusion]

I mean… ugh maybe I’ll get a CSV! I should have rephrased the above to ask what I really mean which is “that’s a $250 valve and a pressure tank is half that price, would that help before I spend the money?” Thanks for the explanations to help me understand this. Seems like no matter what I do here, short of reworking the whole sprinkler system to have the same load on each station, the CSV is the only thing that will help.

Also here’s the curve diagram for the pump. It’s a cheaper Vevor 1.5hp pump with pump box. The specs I was stating of going from 24 to 37 gpm were both the pump ratings and I understand I’m my application it wouldn’t produce that maximum. The other pump was a shallow well jet pump where as this is a submersible.

 

[Valveman]

what I really mean which is “that’s a $250 valve and a pressure tank is half that price, would that help before I spend the money?” Seems like the CSV is the only thing that will help.

We have a model that is only 89 bucks. But the CSV1A for $224.00 is probably best for your application, and far more than outweighs its cost. That pump will do about 25 GPM at 50 PSI, so you would need at least one of those 86 gallon size tanks that cost over $500.00. Two of those $500 tanks would be better for that size pump. But a room full of those expensive big tanks cannot do what the Cycle Stop Valve will do. When used with the 4.5 gallon size tank, the CSV is much less expensive than a so called properly sized pressure tank.

Of course if you just want to put a small pressure tank on that big pump it will work. But then you will be calling me with problems like the pressure surging up and down, or the pump, tank, check valve, pressure switch, or other parts failing often because of the pump cycling on and off all the time.

The CSV is not the only way to prevent pump cycling, but it is the best way.

 

[Shallowellconfusion]

You don't need another pressure tank, many sprinkler systems run without one if the zones are sized to the pump. Can you find out if the well ever did supply more water, maybe it just needs cleaning. It's possible to put an acid treatment in a well, let it work for a while, then blow it out with a large air compressor. Then maybe the well will provide enough water for the large pump you already have, otherwise you could put an orifice in the line from the pump to the pressure tank to reduce the amount of water it's actually pumping.

I’ve worked to find any records on the well an and have found nothing so no clue how much it did make. There are some in the neighborhood I could pull up again as references though if that’s helpful at all.

For the acid treatment can you elaborate a bit more? As I look it up the process seems to suggest a complex procedure used in the oil and gas industry but is there something easier for a shallow well like mine. I know there is a lot of course sand in the bottom of the well is that means anything.

 

[Valveman]

There are lots of ways to clean a well. Depends on what kind of well, depth, and what is being cleaned out as to the best method. With a 25' deep well you could easily blow the well with a compressor. You would need a large rental type compressor and probably a stick and a half of 2" steel pipe. Probably even need to put a hold down on the steel pipe to keep it from rocketing out of the well. Plastic pipe would just be harder to hold down. The sand at the bottom of the well will be blown up and out the casing like a geyser. While blowing the sand out, the sand will blast the casing and clean it as well as needed.

Acid and brushing will also help clean the casing and screen. You can find chemical for cleaning wells at Cotey Chemical if you want to go that way.

 

[RS]

A friend of mine did his own, he ran a pipe to the bottom, poured a gallon of muriatic acid down the pipe. that's so the acid gets to the problem area, and not diluted by the water in the well. He let the acid work for a few hours, and then blew it out with a large air compressor, like Valveman said. This procedure works fine, depending on what is plugging the well.

 

[Shallowellconfusion]

A friend of mine did his own, he ran a pipe to the bottom, poured a gallon of muriatic acid down the pipe. that's so the acid gets to the problem area, and not diluted by the water in the well. He let the acid work for a few hours, and then blew it out with a large air compressor, like Valveman said. This procedure works fine, depending on what is plugging the well.

Just to make sure I am understanding When you guys talk about blowing it out are you connecting the compressor to the top of the pipe and then blowing air to the bottom till sand comes up in the casing. Sounds like a 2” pipe and a tow behind my truck compressor? The well casing is 6” so I would need a lot of air.

I ask because I also did a similar thing but ran a pvc pipe with air an air hose connected at the bottom. I rented a compressor but it was just a gas powered one that fit in the back of my truck. I only had moderate success and after a few hours I had about 2.5 gal of sand. I gave up when my time on the rental ran out. I guess the compressor at the top is the same idea but a lot bigger… and I would need a much bigger air compressor.