Submersible pump quality?

[Gecko]

Many threads on this in the past, sound like pump quality has really gone down recently. I'm replacing a 27 year old pump and would like it to last as long as possible. Almost everything out there has a bunch of Chinese plastic parts in it. The only two I've found that might be exceptions are the Grundfos SP which has sheet metal impellers I think, and the AY McDonald 26000 series which is also all stainless. It's not clear in that one how the impellers are made. They are about the same price. This is probably a 20-25 gpm, 1.5-2hp 3ph installation. I believe what's in there is a 1.5hp 1ph. It is used for both the house and some irrigation.

The well is 190' but the pump is only 63' down. The water isn't sandy, but there is some rust grit that comes through from the 70 year old 8" iron casing. Maybe a bigger problem is the iron and/or manganese bacteria which can clogs things.

Any opinions on the Grundfos SP or AYM 26000? Is Franklin still the best motor? The Grundfos tends to be sold with their motor, though I can get the pump head and Franklin motors separately. The AYM26000 seems to come with a Franklin motor typically.

Thanks for your opinions.

 

[ThirdGenPump]

If you want to mess with it yourself the Grundfos is really easy to pull apart and clean if you have issues with pumps getting plugged up.

I don't find AY McDonald's pumps to be anything special. I like AY McDonald's brass products and am happy to have a local distributor but I've never had interest in their pumps.

Franklin motors are about the same as anyone else's these days. They are riding on the reputation of their older American made motors. They no longer make them in the US and their quality reflects that.

The motor that comes with the Grundfos is the best option of the 2 imo.

 

[Sponsor]

 

[Gecko]

Yeah most of AYM pumps look about the same as anyone else's, the 26000 caught my eye for being stainless steel all the way through.

 

[Valveman]

Yeah most of AYM pumps look about the same as anyone else's, the 26000 caught my eye for being stainless steel all the way through.

Yeah those have plastic impellers in a Stainless Steel can. A lot of companies do that and call it Stainless Steel, but the main parts are plastic. Still maybe a good pump, but not Stainless all the way through like they say.

I agree with Grundfos SP as being the best. But switching to 3 Phase is going to be your problem. That means you would need a VFD to convert your regular single phase house current to three phase. Then even though the VFD will give you constant pressure and allow the use of a small tank, the VFD will be your problem, not the pump. The only way to make a pump last 27 years again, would be to use the same kind of control system, but just reduce the number of on/off cycles from previous times.

 

[Gecko]

I already have 3 phase power at the pump, no converter needed. To go variable speed, yeah then a VFD is needed.

I'd like to stop cycling for irrigation use when it cycles every few minutes, and I think either a VFD or CSV would do that. But another primary consideration is keeping the pressure at or near the maximum all the time. Problem there is that the house is somewhat above the pump equipment, so at the bottom of a 40-60 psi typical cycle, the pressure on the top story of the house is pretty low. I really don't want the complication of a pressure pump at the house. My reservation on the CSV is that all of the pressure switches I've used will not reliably set and hold a 5 psi dead band. I know Amtrol makes an electronic one but reports on it are that it is very unreliable. With an appropriate pressure switch, it should be possible to run say 60 - 65 psi, with a largish pressure tank, and a CSV. Pump would cycle some with household use which is light and intermittent, but stay on for showers and irrigation. Who makes a pressure switch that can be set that closely, will not drift off with time and temperature?

 

[Valveman]

I use a lot of Allen Bradley 836C7A pressure switches. They have a 2 to 25 psi bandwidth. Work great. I use them on systems with 3 to 15 pumps on the same line. Expensive. Won't handle even 1/2 HP current. Got to use a contactor. Need a contactor with a 3 phase motor anyway.

With a small tank the 20 psi differential is inconsequential anyway. 10 gallon tank holds 2 gallons of water. Pump will be on and up to the constant pressure of the CSV before you get temp adjusted in shower.

I would use a single phase pump on two of the three phases so I could use a regular single phase motor, and no contactor.

PK1A with 10 gallon tank. 50/70 pressure switch. CSV1A will give 60 psi constant and you won't even need soap in the shower.

 

[Gecko]

Already have the 3 phase contactor in place. I'd always intended to put a 3 phase in someday. Already have two 119 gallon tanks. Question is, how much water can be drawn from them before pump turns on with CSV? Say switch is set to 60-70 psi. I think I would set the tank pressure to 60 or 55 psi. I think I get 17 gallons draw down on each 119 gallon tank? It'd still come on in a shower, but not for most other household use.

It there any merit to the soft start argument on a 3 phase pump VFD. This pump was set on iron pipe and I'd probably use iron again. Thinking about starting torque. Don't want a torque reactor because of the old 8" iron casing. One pump guy here says put it in with sch120 PVC, but that seems a bit fragile compared to 1 1/4 steel pipe. I'd prefer to go 3 phase as there is no starting timer/cap nonsense.

Thanks for the tip on the pressure switch, I'll look them up.

 

[Valveman]

Not really just a contactor needed but a motor starter, which has built-in overloads. Small single phase submersibles have overloads in the motor, three phase motors do not.

With a 40/60 pressure switch a 119 gallon tank holds 31 gallons. With a 50/70 pressure switch it only holds 28 gallons. Cut the pressure switch bandwidth in half to 60/70 and the tank only 14 gallons of water. With a 5 PSI bandwidth (65/70) it only holds 7 gallons of water. Two of those 119 gallon tanks would bring you back to 14 gallons, which is a lot of wasted space in tanks that could give you 60 gallons of water before the pump comes on.

Soft starting the pump/motor by reducing the torque is good, as long as it is not done with a VFD. A VFD ramps up slowly, and the thrust bearing doesn't get any film of water for lubrication until the pump is up to 50% speed (30hz). So you would need a VFD that will ramp up to 50% speed within one second, and then soft start from there up. Most domestic VFD's are cheap and do not have that option. A motor actually has less wear starting across the line at full torque, than ramping up to 30hz slowly.

Reduced voltage soft start is the best, as it doesn't ramp up to speed. And a reduced voltage soft start can be had by just not over-sizing the wire to the pump. The following is from Franklins AIM manual found here.
http://www.franklinwater.com/media/110562/M1311_60_Hz_AIM_12-14-WEB.pdf

Reduced-voltage starters may not be required if the maximum recommended cable length is used. With maximum recommended cable length there is a 5% voltage drop in the cable at running amps, resulting in about 20% reduction in starting current and about 36% reduction in starting torque compared to having rated voltage at the motor. This may be enough reduction in starting current so that reduced-voltage starters are not required.

In other words, if you use the longest length of the smallest wire possible for the horsepower of the pump, you get a natural soft start with 36% reduction in starting torque. A 2HP pump using 150' of #14 wire makes a natural soft starter. That will be hard to do with a three phase motor as you would need to stretch out 320' of #14 wire for a 60' well.

However, starting torque only happens during pump start. So if you don't start (cycle) the pump very much, you don't need to worry about starting torque. I only see problem with starting torque when the pump is allowed to cycle too much. This is more of the case in small casing than in 8" casing like yours. The biggest problem with starting torque is wearing out the wire as it slaps against the casing and drop pipe. It doesn't slap against 8" casing as bad as it does 4" casing. No need at all for torque arrestors with steel drop pipe.

There won't be enough torque in a 60' deep setting to cause a problem with plastic pipe either. Steel pipe in a well like that is rare these days, as plastic is plenty tough and won't rust out. Using double jacketed wire and taping it to the pipe good is the best way to not have to worry about starting torque.

The most important thing to add in 8" casing is a 4" shroud over the pump. This will protect the pump from banging against the casing, and make sure the water flows close to the motor to keep it cooler.

A CSV also gives a mechanical soft start. Starting the pump against an almost closed valve is good for the pump. The inrush amps are greatly reduced that way. Either the CSV and/or the long length of small wire will give you all the soft start needed.

You only have 1.5 or a 2HP pump setting at 60', you are making a mountain out of a mole hill. I would use #14 wire, a PK1A with a 10 gallon tank, and a regular 50/70 switch. You can probably ebay those two big tanks to someone who doesn't realize they are dinosaurs, for enough to cover the entire costs of everything else.

Oh and PS: I have those Allen Bradley switches on the shelf if you need one for $375.00.
See here...
https://cyclestopvalves.com/collections/pressure-switches/products/allen-bradley-pressure-switch

 

[Gecko]

Wow you were right about that pressure control being pricey! The cheap Flotrol ones I've used are $20-30. But they create problems.

Good tip on using minimum sized wire, not sure it will help me though, there is #10 running to the well service. The contactor that is already in place is a 3 phase motor starter with overloads.

The existing pump didn't have a flow shroud, and we do not know where the water is coming in anyway (above or below the pump) so I guess I should have a shroud. It I set a 2hp at 60' again, is torque on 1 1/4 sch120 pvc a problem?

Thanks for your help on this. I'm thinking 1.5 or 2 hp 3 ph Grundfos with shroud, keep one of the tanks, cycle stop valve, set to run between 60-70. On the tank is seems like a trade off of number of starts vs. time running at minimum flow. Small tanks means more starts (with intermittent faucets opening and closing) while big tanks mean running longer at low flow to top them up.

 

[Valveman]

Sch 120 is fine, but I still prefer double jacketed wire to go with it.

I have explained it a million times, but "intermittent faucets opening and closing" even flushing toilets isn't what causes cycling, as very little water is used this way. The CSV eliminates the cycles for long term uses like showers and sprinklers, which takes out so many cycles you would never be able to add them back with hand washing and toilet flushing. Even without any outside watering the number of cycles per day is the same with a CSV and small tank, as with a larger tank. It is just how the cycles accumulate that is different. With the CSV there is no cycling for long term water uses, which use to cycle the pump dozens or hundreds of times, but a few more cycles for toilet flushes. The number of cycles are the same. If you do any outside watering there is no comparison as to how many cycles the CSV will save. And while you are running a sprinkler(s) outside, the pump is already running and using water in the house doesn't add a single cycle.

Even with one huge tank and a 60/70 pressure setting you are not going to like waiting on the 14 gallons in that tank to be used as the pressure drops from 70 to 60. Pressure coming out of the tank is decreasing and not as strong as when water is coming from the pump and CSV. But you will get use to it and be able to tell when the pump comes on as the pressure will get stronger. And no matter what size tank you use, the CSV is set to only take a couple minutes to fill the tank. In your case with a 60/70 pressure switch, you would set the CSV1A for 68 PSI. Then it only takes 2 minutes for the CSV to fill the tank from 68 to 70.

Even a 10 PSI bandwidth pressure switch is hard to find, most only go down to like 17 PSI at best. I have a discontinued electronic switch you can use marked down to 30 bucks. They work great as long as they are working. But like anything electronic, it will quit you without notice someday. See it here.
https://cyclestopvalves.com/collections/pressure-switches/products/electronic-pressure-switch-1

 

[Gecko]

The specs on the Allen Bradley switch suggests a bandwidth of 10 psi is possible? Specs say down to 2 psi.

I thought I fully understood the CSV but maybe not. Here is my understanding: It is a pressure regulator with a minimum flow of 1 gpm. It stops cycling when continuous water use exceeds 1 gpm by preventing the system pressure from reaching the shut off point of the pressure switch.

But discontinuous flow is considerably more complicated. If I have a very small pressure tank, when I turn on the kitchen faucet, the pressure will drop from 70 to 60 psi very quickly, and the pump will come on. The pressure will then rise very quickly until it reaches the 68 psi set point of the CSV, and will remain on as long as the kitchen faucet draws more than 1 gpm. This means there will be one pump cycle for every opening of a faucet, every toilet flush, etc. That may only be 40 or 50 cycles per day, but it is cycles. We irrigate only in the middle of the night, so this will not be covered by irrigation cycles.

If instead I have a large pressure tank, when I turn on a kitchen faucet, it will draw down the pressure tank. With the 28 gallon capacity of the two existing pressure tanks (operating between 6o and 70 psi) I can run the 1 gpm kitchen faucet for 28 minutes (or 28 times for 1 minute), or flush the 1.6 g toilet 17 times, before the pressure is reduced to the 60 psi turn on set point of the switch. Therefore during the day household use may only cycle the pump once or twice.

For continuous use, the CSV reduced the pump cycles, but for intermittent use the pressure tank reduced the pump cycles. The two do not interfere with each other, rather they compliment each other and you can benefit from both. There is one additional (minor) benefit of the larger tanks, most household water would be supplied from water pumped at the capacity of the pump, stored in the pressure tank. The pump is more energy efficient when pumping at capacity, than when pumping at 1 gpm. Every cycle, the pump will need to finish the last 2 psi (68 -> 70) at 1 gpm, but that is only 5 gallons/cycle, and the number of cycles will be reduced to a very few per day.

I can see only one downside of this beyond the expense for the tanks themselves which is a sunk cost in my case. That is the pressure variation will be different when a faucet is turned on. It may be 60 psi for the entire 1 minute that it is on. With a small tank it would start at 70 psi, reduce to 60 psi, then climb back to 68 psi each time. If the difference between 68 and 60 psi at the kitchen faucet was significant in usability, then the small tank might be preferable, though I will still see the sag every time it is turned on. In my case 60 psi is fine, it is 40 psi that is a problem.

What have I gotten wrong there? If you had to chose between a CSV and a large pressure tank, perhaps the CSV is better, but if you can have both, what is the downside?

 

[VAWellDriller]

The specs on the Allen Bradley switch suggests a bandwidth of 10 psi is possible? Specs say down to 2 psi.

I thought I fully understood the CSV but maybe not. Here is my understanding: It is a pressure regulator with a minimum flow of 1 gpm. It stops cycling when continuous water use exceeds 1 gpm by preventing the system pressure from reaching the shut off point of the pressure switch.

But discontinuous flow is considerably more complicated. If I have a very small pressure tank, when I turn on the kitchen faucet, the pressure will drop from 70 to 60 psi very quickly, and the pump will come on. The pressure will then rise very quickly until it reaches the 68 psi set point of the CSV, and will remain on as long as the kitchen faucet draws more than 1 gpm. This means there will be one pump cycle for every opening of a faucet, every toilet flush, etc. That may only be 40 or 50 cycles per day, but it is cycles. We irrigate only in the middle of the night, so this will not be covered by irrigation cycles.

If instead I have a large pressure tank, when I turn on a kitchen faucet, it will draw down the pressure tank. With the 28 gallon capacity of the two existing pressure tanks (operating between 6o and 70 psi) I can run the 1 gpm kitchen faucet for 28 minutes (or 28 times for 1 minute), or flush the 1.6 g toilet 17 times, before the pressure is reduced to the 60 psi turn on set point of the switch. Therefore during the day household use may only cycle the pump once or twice.

For continuous use, the CSV reduced the pump cycles, but for intermittent use the pressure tank reduced the pump cycles. The two do not interfere with each other, rather they compliment each other and you can benefit from both. There is one additional (minor) benefit of the larger tanks, most household water would be supplied from water pumped at the capacity of the pump, stored in the pressure tank. The pump is more energy efficient when pumping at capacity, than when pumping at 1 gpm. Every cycle, the pump will need to finish the last 2 psi (68 -> 70) at 1 gpm, but that is only 5 gallons/cycle, and the number of cycles will be reduced to a very few per day.

I can see only one downside of this beyond the expense for the tanks themselves which is a sunk cost in my case. That is the pressure variation will be different when a faucet is turned on. It may be 60 psi for the entire 1 minute that it is on. With a small tank it would start at 70 psi, reduce to 60 psi, then climb back to 68 psi each time. If the difference between 68 and 60 psi at the kitchen faucet was significant in usability, then the small tank might be preferable, though I will still see the sag every time it is turned on. In my case 60 psi is fine, it is 40 psi that is a problem.

What have I gotten wrong there? If you had to chose between a CSV and a large pressure tank, perhaps the CSV is better, but if you can have both, what is the downside?

You've explained it perfectly....the only down side to the larger tank install is waiting for constant pressure to kick in. I install csv style valves with 20 gallon tank on every normal residential installation. 20 gallon tanks are by far the most common size manufactured, and are very inexpensive. One consideration you should take into account if you get the stainless csv that comes with the side kick is the headloss through the valve. You can really get in trouble with a narrow band pressure switch and/or smaller tank if you don't plan for it. If you set the valve for 15 gpm irrigation at 60 psi...the csv will hold 60 great; then when you get in the shower at standard 2.5gpm, the csv will be trying to hold about 70 because of less pressure loss at lower flow (have to check table I'm just guessing from memory).....If the switch is set wrong you will have a short cycling pump. Likewise, if you set the valve at 60 psi for shower, and then turn on large irrigation demand, the valve will hold a substantially lower constant pressure. With the adjustable valves, you have to pick a specific flow range and pressure and set the switch accordingly. The fixed plastic CSV have much lower friction loss.

 

[Valveman]

The specs on the Allen Bradley switch suggests a bandwidth of 10 psi is possible? Specs say down to 2 psi.

I thought I fully understood the CSV but maybe not. Here is my understanding: It is a pressure regulator with a minimum flow of 1 gpm. It stops cycling when continuous water use exceeds 1 gpm by preventing the system pressure from reaching the shut off point of the pressure switch.

But discontinuous flow is considerably more complicated. If I have a very small pressure tank, when I turn on the kitchen faucet, the pressure will drop from 70 to 60 psi very quickly, and the pump will come on. The pressure will then rise very quickly until it reaches the 68 psi set point of the CSV, and will remain on as long as the kitchen faucet draws more than 1 gpm. This means there will be one pump cycle for every opening of a faucet, every toilet flush, etc. That may only be 40 or 50 cycles per day, but it is cycles. We irrigate only in the middle of the night, so this will not be covered by irrigation cycles.

If instead I have a large pressure tank, when I turn on a kitchen faucet, it will draw down the pressure tank. With the 28 gallon capacity of the two existing pressure tanks (operating between 6o and 70 psi) I can run the 1 gpm kitchen faucet for 28 minutes (or 28 times for 1 minute), or flush the 1.6 g toilet 17 times, before the pressure is reduced to the 60 psi turn on set point of the switch. Therefore during the day household use may only cycle the pump once or twice.

For continuous use, the CSV reduced the pump cycles, but for intermittent use the pressure tank reduced the pump cycles. The two do not interfere with each other, rather they compliment each other and you can benefit from both. There is one additional (minor) benefit of the larger tanks, most household water would be supplied from water pumped at the capacity of the pump, stored in the pressure tank. The pump is more energy efficient when pumping at capacity, than when pumping at 1 gpm. Every cycle, the pump will need to finish the last 2 psi (68 -> 70) at 1 gpm, but that is only 5 gallons/cycle, and the number of cycles will be reduced to a very few per day.

I can see only one downside of this beyond the expense for the tanks themselves which is a sunk cost in my case. That is the pressure variation will be different when a faucet is turned on. It may be 60 psi for the entire 1 minute that it is on. With a small tank it would start at 70 psi, reduce to 60 psi, then climb back to 68 psi each time. If the difference between 68 and 60 psi at the kitchen faucet was significant in usability, then the small tank might be preferable, though I will still see the sag every time it is turned on. In my case 60 psi is fine, it is 40 psi that is a problem.

What have I gotten wrong there? If you had to chose between a CSV and a large pressure tank, perhaps the CSV is better, but if you can have both, what is the downside?

You thinking like most of us pump installers did a quarter of a century ago when we first started using Cycle Stop Valves. And you are exactly right. We have just learned over the years through trial and error that large tanks don't help enough to justify the expense and space. Cycling a pump 30 or 50 times a day is not going to shorten its life considerable compared to 5 or 10 cycles per day. 100 to 300 cycles per day are the numbers we are trying to stay away from. There are probably more benefits to a smaller tank than a larger one. Some people don't like their water sitting long enough to get room temperature in a big rubber bag type tank. With a small tank you only have to let a gallon or so go down the drain or use for washing your hands, before you are getting fresh, cool water straight from the aquifer, with no rubber taste. The drop in pressure to start the pump happens so fast it isn't noticeable. So you get strong constant pressure for everything you do. We already mentioned how much those big tanks cost. There is also the cost of the square feet needed to house them, and warming a few hundreds gallons a day to room temp can add more to the heating bill than you think.

The only real concern for energy is with irrigation or heat pumps. And then if you run large zones there is no difference in the electric bill compared to running the same large zones without a CSV. The average house only uses 200-300 gallons per day. And with the average electric rates that only adds up to about 5 bucks a month. The extra run time for using a CSV and small tank can increase that to 7 bucks a month. Which is much less than it take to heat the room and the water for a large tank.

Like VA says a 20 gallon tank is about as large as you want to go these days. And he is being very conservative with that. All of this has been tested for years. 25 years ago we switched form 80 gallon tanks to 20 gallon with a CSV. 15 years ago many pump installers went from the 20 gallon tank to a 2.2 gallon when using a CSV. I am still being conservative saying you need at least a 4.5 gallon size tank. Many of my good pump installer customers say the 4.5 isn't necessary, as the 2.2 gallon systems are lasting a long time. I only offer a 4.5 or a 10 gallon tank to be on the safe side. But I am really just offering the 10 gallon tank to give people that warm and fuzzy feeling, as newcomers to the constant pressure systems still think the larger tank the better, just like you. A good thing about the CSV is that it will work with any size tank you want to use. But any size tank you use is usually not large enough without a CSV.

 

[Gecko]

OK great, I think we are on the same page. The tanks in this case are about 600 ft from the house and not heated. Water from a faucet will have been sitting in the pipes, not the tank or the well. Actually there is a 100 gallon dwell tank for the treatment system too, so it takes awhile for water to get from the pump to the house.

Now on this pressure loss thing. I'd like to get as close to 70 psi as possible for the house use, particularly the showers which are low flow by law, 2 gpm I think. On the other hand the irrigation uses as much as 20 gpm, but could also run at a lower pressure. If I understand it, I would set the CSV for 68 psi (this would be it pressure at 1 gpm), the pressure switch at 60-70, and what I'd expect at 20 gpm is 10 psi less or 58? That would be fine for the sprinklers - as it is they go between about 45 and 65. Or would I see the 10 psi loss from friction, and an additional 10 psi from pressure fall off? That would put the sprinklers down at 48 and now things aren't looking so good. There does not seem to be a similar spec for the plastic valve.

I can't go higher in pressure as parts of the treatment system are limited to 75 psi.

 

[Valveman]

You never did say which pump for sure you were using or how deep it is to water in the well? Without that info I can't tell if 10 PSI friction loss is going to be a problem for you or not. Usually not, as pumps are normally way oversize, which is why a CSV is needed in the first place. Friction loss through a CSV only matters when trying to run the pump at max flow. It is rare for max flow of the pump to ever be needed. Sprinkler systems are usually sized smaller than the max flow of the pump, so you have a little water left for house use. If you have a 25 GPM pump and the largest sprinkler zone is 20 GPM, the CSV always has to put a little extra friction loss on the pump to keep it from pumping too much water and cycling on and off repeatedly, making the actual friction loss through a CSV a moot point.

If you want 70 PSI in the house then set the CSV1A to 70 PSI. With the CSV set to 70 for the house, you will still have 60 when running the large sprinkler zones. With those large tanks you will want to shut the pump off at about 72-73 anyway, so it won't get to the 75 max pressure of your filter system. Where it starts isn't really important, except that you will be at that low pressure until the pump starts.

Like I said the only pressure switch I have that will do 10 PSI between on and off is the electronic model EPS15/99. Have you found any other regular mechanical pressure switch that will do less than 20 PSI bandwidth? Best your going to get with the standard switch is about 17 PSI band, by loosening the small adjustment screw all the way out.

The plastic CSV125 valves do not have any reduced pressure fall off and almost no friction loss. A 60 PSI CSV125 will hold 60 PSI through the entire flow range of the pump. But they will start leaking a little from the vents if you have sand, iron, or anything slimy or abrasive in the water. And since you are using a filter, that maybe a problem. These valves have the best flow characteristics of any valve I have, but you need fairly clean water for them to last a good length of time. They are only 63 bucks so you can replace them if they start leaking fairly inexpensively. If you only have to replace them every 5 years or so that isn't too bad. But if you have to replace them every 6 months or so, I recommend switching to the CSV1A. The CSV1A is designed to handle iron and sand, but there is more friction loss and reduced pressure fall off as a trade off.

 

[Gecko]

I think I said upthread, this is a 190' well with the water standing typically 35' below the surface but can get pulled down to 45'. With an open pipe and continuously running pump it can be pumped below the intake. The pump has been set on 3 lengths of iron or 63' but I'm thinking I should add another 20'. Also the water table is historically dropping in this area. I'm planning a 1.5 or 2.0 hp pump, the sprinklers are rainbirds and running 2 will be 20 gpm. Looking at a Grundfos SP pumps, the two choices seem to be the SP25S or the SP16S. 20 gpm is a little past the peak efficiency for the 16, the 25 is near peak efficiency at 20 gpm. But the 25 takes a 1 1/2" pipe, not sure if I could neck that immediately at the pump. All the other well plumbing is 1 1/4, the well is only 20' away from the tanks, treatment, and distribution. With either of them, 1.5 hp barely gets you to 20 gpm at 200' head, not a lot of headroom over the initial requirements. But I think equivalent to what's in there now. 2.0 hp allows for a dropping water table in the future.

What you're telling me though is there are downsides to overspecing the pump. I need 65-70 psi for the house at not more than 10 gpm and typically less, but I'd like 20 gpm for irrigation preferably at 55+ psi. The two uses are usually time offset.

The water isn't sandy, but very hard (300 - 400 TDS) and there is grit and rust in it from the old iron casing, not sure how long the plastci valve would survive I also plan to recase with a PVC casing and gravel packing, but I don't think that will entirely solve the grit problem. Can I recase an 8" with 6" PVC? Local well guy wants to do it in 5".

 

[Reach4]

Here is an idea... CSV and pressure tank and pressure switch are at the house providing 70 psi. Irrigation water tees off before. You set up the irrigation so that it consumes only enough water to keep the pressure at 55+. During irrigation, the house pressure drops.

Just musing.... there may be something I don't foresee.

 

[Valveman]

Here is an idea... CSV and pressure tank and pressure switch are at the house providing 70 psi. Irrigation water tees off before. You set up the irrigation so that it consumes only enough water to keep the pressure at 55+. During irrigation, the house pressure drops.

Just musing.... there may be something I don't foresee.

No your not missing anything. That is a good idea. But if you don't size every sprinkler zone exactly to the pump, the pump will still cycle on/off while running that zone. If the pump can do 16 GPM, and the zone is only 15 GPM, the pump will cycle according to the tank size. But that way you don't have to worry about friction loss or reduced pressure from the CSV. Usually better to size the zones to the yard, and let the CSV size the pump to the zone. But the old way of sizing every zone perfectly to the pump still applies if you can find someone who knows how to make that happen.

Here is a curve for the 25S20-11. It shows from 45' lift and 70 PSI, including 10 PSI friction loss for the CSV1A, and it will still do 23 GPM (TDH 230'). The back pressure from the CSV will be a max of 130 PSI. Same pump I have at my house. It will go from 2.3HP at full flow to 0.7HP at 1 GPM flow. It is a very good pump to work with a CSV. This is plenty of pump so you don't have to worry about friction loss unless you try to use more than 23 GPM.

Doesn't matter what pipe size comes out of the pump. Just bush it to 1 1/4 as your only going 60-80' or so.

 

[VAWellDriller]

I think I said upthread, this is a 190' well with the water standing typically 35' below the surface but can get pulled down to 45'. With an open pipe and continuously running pump it can be pumped below the intake. The pump has been set on 3 lengths of iron or 63' but I'm thinking I should add another 20'. Also the water table is historically dropping in this area. I'm planning a 1.5 or 2.0 hp pump, the sprinklers are rainbirds and running 2 will be 20 gpm. Looking at a Grundfos SP pumps, the two choices seem to be the SP25S or the SP16S. 20 gpm is a little past the peak efficiency for the 16, the 25 is near peak efficiency at 20 gpm. But the 25 takes a 1 1/2" pipe, not sure if I could neck that immediately at the pump. All the other well plumbing is 1 1/4, the well is only 20' away from the tanks, treatment, and distribution. With either of them, 1.5 hp barely gets you to 20 gpm at 200' head, not a lot of headroom over the initial requirements. But I think equivalent to what's in there now. 2.0 hp allows for a dropping water table in the future.

What you're telling me though is there are downsides to overspecing the pump. I need 65-70 psi for the house at not more than 10 gpm and typically less, but I'd like 20 gpm for irrigation preferably at 55+ psi. The two uses are usually time offset.

The water isn't sandy, but very hard (300 - 400 TDS) and there is grit and rust in it from the old iron casing, not sure how long the plastci valve would survive I also plan to recase with a PVC casing and gravel packing, but I don't think that will entirely solve the grit problem. Can I recase an 8" with 6" PVC? Local well guy wants to do it in 5".

You'll have a hard time getting those 2 different flow ranges and desired pressures with a csv product. You would be better with their plastic one because of the headless problems, but 60 psi is the highest they got. There ARE situations where a VFD meets the water requirements better and this might be one...I've had good luck with franklin sub drives...you'll just punch in desired pressure and that's it.

As far as reline.....you CAN do a 6 in an 8.....but wont do a very good job. I recline a lot of public higher producing wells....and like to install a mirrored well screen placement and have room to get in a good gravel pack and grout. In your case a pvc 4.5" or 5" casing would allow you to do a really good job and make the well last forever. There is no benefit to using 6". We reline a lot of 6" wells with flush joint pvc so there is room for gravel and grout.

 

[Valveman]

You'll have a hard time getting those 2 different flow ranges and desired pressures with a csv product.

Actually those are exactly the desired flows and pressures from the CSV1A. Setting the CSV1A at 70 PSI for a 3 GPM shower at the house, would mean the 20 GPM sprinkler zones would run at 60 PSI. Pressure switch setting of about 60/75 would allow the use of about 40 gallons of water from two 119 gallon tanks before the pump comes on.

Are they still using the little 2 PSI pressure switches with those subdrives? I agree that would keep the pressure between 68 and 70 all the time, but you would only be getting about 3-4 gallons from both of those big tanks before the pump comes on. That 2 PSI pressure switch has always been a problem. If it takes two 119 gallon tanks to get 4 gallons of draw down with a 2 PSI switch, you normally can't get a class of water without the pump starting when using a smaller tank. Yet they only recommend what, a 8 gallon size tank on a 2HP with a subdrive? Using an 8 gallon tank with a subdrive and 2 PSI pressure switch means the tank only supplies a cup of water before the pump starts. For some reason people don't seem to think it is a bad thing for the pump to start every time they just crack a faucet open when they have a VFD, but when using a CSV they think they need two 119 gallon tanks. I just don't understand it! Because of the regular 20 PSI pressure switch bandwidth, a CSV always allows the use of all the water from any size tank before the pump comes on. Subdrives and SQE's only use a 2 PSI bandwidth, so you only get 1/10th the full draw down from any tank before the pump comes on. But that's OK? Go figure!