PDA

View Full Version : Pump with pressure tank question.


jcom
06-18-2008, 09:09 AM
We are set to start an installation where the customer has had a well drilled. There is a pressure tank sitting next to the pump casing and they have left a 1" pump outlet for us.

Of course we will do a flow and psi test before design. The pump is wired to a pressure switch by the tank. The pumps we have put in before have not used a pressure switch to avoid excessive cycling of the pump. My thinking is that the tank will alleviated this problem and the pressure switch is ok.

We plan to come off the outlet to a manifold and mainline and turn the pump on. When a valve opens the pump will start etc. etc..

Is my thinking all messed up or workable.

I know you gurus are here!

John

Dripit good
06-18-2008, 09:29 AM
We are set to start an installation where the customer has had a well drilled. There is a pressure tank sitting next to the pump casing and they have left a 1" pump outlet for us.

Of course we will do a flow and psi test before design. The pump is wired to a pressure switch by the tank. The pumps we have put in before have not used a pressure switch to avoid excessive cycling of the pump. My thinking is that the tank will alleviated this problem and the pressure switch is ok.

We plan to come off the outlet to a manifold and mainline and turn the pump on. When a valve opens the pump will start etc. etc..

Is my thinking all messed up or workable.

I know you gurus are here!

John

How old is the tank.......and is it exposed to the elements? If new you should be fine with what you plan to do. If old and not brought inside for the winter, the bladder could be shot rendering it useless.

jcom
06-18-2008, 10:10 AM
All is new.

Wet_Boots
06-18-2008, 10:25 AM
Run a serious test on that well. an hour's pumping might not reveal a problem that two hours pumping would. (This is about low replenishment rates, as you pump out water) ~ When you determine the flows that give you constant operation, you can design a proper system.

You should specify a controller that has a programmable delay between zones, on the off chance that you have a well that can run dry, which would have to sit idle, while it refills.

Dripit good
06-18-2008, 10:26 AM
Don't forget about your back flow assembly before your manifold.

Valveman
06-18-2008, 10:32 AM
You don't want to make the pump start relay in the sprinkler controller override the pressure switch. Let the pressure switch start the pump when the zone valves open. Now all your zones have to exactly match the output of the pump to keep it from cycling. Or you can use a Cycle Stop Valve before the pressure tank. This will allow you to match the zones to the irrigation required, without having to match all zones to the maximum output of the pump. If the zones don't max out the pump, the home owners will still have good "constant pressure" even while the sprinklers are on. If the zones max out the pump, there is very little left for the house.

Dripit good
06-18-2008, 10:32 AM
Run a serious test on that well. an hour's pumping might not reveal a problem that two hours pumping would. (This is about low replenishment rates, as you pump out water) ~ When you determine the flows that give you constant operation, you can design a proper system.

You should specify a controller that has a programmable delay between zones, on the off chance that you have a well that can run dry, which would have to sit idle, while it refills.

Yes, yes! We have two systems we service that run out of water within 45 minutes of run time, that takes approximately 2 hours to recover.

AI Inc
06-18-2008, 01:43 PM
Run a serious test on that well. an hour's pumping might not reveal a problem that two hours pumping would. (This is about low replenishment rates, as you pump out water) ~ When you determine the flows that give you constant operation, you can design a proper system.

You should specify a controller that has a programmable delay between zones, on the off chance that you have a well that can run dry, which would have to sit idle, while it refills.

Definatly listen to this guys advice. Run a hose into the woods and let it run wide open. Drain your staorage then you can get a real reading of what the well is producing.

Valveman
06-18-2008, 05:09 PM
You certainly need to know how much the well and the pump will produce. You should test the well at least as long as the irrigation will be running. It is possible that you can have a 20 GPM pump but, the well will only produce 15 GPM for an extended period of time. In this case you can't set the zones to 20 GPM or the well will go dry, and you can't set the zones to 15 GPM or the pump will cycle on and off. Using the CSV, you can set the zones to 15 GPM and the pump will not cycle.

The same way a CSV will allow you to design the zones to match varied irrigation requirements, it will also let you vary the zones to match the amount of water available from the well. So if the well test out to make 17 GPM, you can use a 20 GPM pump, and still design each zone for only 17 GPM without the pump cycling.

Puttinggreens
06-19-2008, 10:29 AM
Please explain how the cycle stop valve works.

Dirty Water
06-19-2008, 11:48 AM
Please explain how the cycle stop valve works.

Pixie dust.

Valveman
06-19-2008, 12:02 PM
Nothing magic about it. With a 40/60 pressure switch, a 50 PSI CSV will hold the system at 50 PSI steady as long as you are using at least 1 GPM. This keeps the pump from filling the pressure tank and shutting off, even if it is a 20 GPM pump and your zones are only using 3 GPM. With a 20 GPM pump, the CSV will vary the flow from the pump to match the usage, and zones can be sized anywhere from 1 GPM to 20 GPM. The CSV can't close to less than 1 GPM, so when there is no more water being used, 1 GPM still comes through the CSV, has no place left to go except the pressure tank, and the tank then fills to 60 PSI and the switch shuts off the pump.

This allows you to match the zones to varied irrigation demands, or to the out put of the well. If all your zones can't be 20 GPM, then the CSV lets you use a 1 GPM zone, a 3 GPM zone, a 17 GPM zone, and still 20 GPM when needed. If your well can't make 20 GPM and the pump sucks the well dry when using over say 12 GPM, then a CSV will allow you to set up the zones for 12 GPM or less without having to install a smaller pump or timing between zones.

jcom
06-22-2008, 09:10 AM
My vendors don't know anything about a cycle stop valve. Where do I buy one?

John

Wet_Boots
06-22-2008, 09:16 AM
My vendors don't know anything about a cycle stop valve. Where do I buy one?

JohnJDL can get you one, if you're okay with cutting it in upstream of the pressure tank. And if you really need it. You want to make that extended flow test before you make plans.

jcom
06-22-2008, 09:20 AM
Our flow test on this valve is very erratic.

When we close the ball valve on the 1" outlet to hold 40 psi., the flow is less than 6gpm.

When we open the ball valve and let psi drop to the 33 psi range, we can flow 20 gpm. Well has a pressure tank and a 30-50 pressure switch which I want changed to 40-60. My thinking is that we have 300 feet to the farthest head and we won't have ample psi to push the sprinklers at the end.

We can feel the pump cycling as we hold the ball valve open. How do we get it to stay on to get an accurate flow test? If we open the valve wide open, we have a heck of a lot of water coming out of course, but the psi drops to nothing.

Goulds 1 1/2 h.p, 100' well.

I know I am missing something here.

John

AI Inc
06-22-2008, 09:23 AM
wow , that is a long way to be pulling water.

Wet_Boots
06-22-2008, 09:25 AM
If you aren't physycally next to the pressure switch when the test is happening, get there, and find a state of steady operation. Go ahead and bump up the switch settings. Is this an irrigation-only well?

jcom
06-22-2008, 09:39 AM
Thanks WB. We will go out today and bump up the settings and see what flow we can get while keeping the pump running.

We just finished a job with a 1 hp. Goulds in the river on a pump start relay with no switch or tank and it works great. We were hoping for good gpms out of this well.

John

Waterit
06-22-2008, 11:51 AM
Can you eliminate the pressure switch and go straight pump-start?

And what flavor 1-1/2HP Gould? Model number, please!

Wet_Boots
06-22-2008, 12:02 PM
I much rather look for keeping pressure switch controls in place, because they protect against closed zone valves. There is really no excuse for not knowing the performance of a well, if you're taking on the job of designing/installing a sprinkler system.

jcom
06-22-2008, 01:10 PM
Just got back from the well and did some more testing so that some more info might be useful.

We made sure that the pump remained running and then did the flow test. It will maintain about 32 psi. after closing down the 1" ball valve enough and still have decent flow. Again, in the 20 gpm area. If we shut the ball valve further to gain 40 psi., the flow drops off below 6 as I stated before.

If we shut the valve off when we have the 32 psi., it takes 45 seconds before the pressure will build to kick out the pump. I am a bit of a pump newbie but this would seem to be too long given the pump size, etc..

I don't know the exact model # of the pump but the driller said it was the 10 series. The driller is supposed to meet me at the well site tomorrow and see what is up with this setup.
He maintains that the hose bib next to the ball valve will flow at 15 gpm and 47 psi.. I told him that if that was true, we should be able to get the same specs. from the 1 " outlet by shutting off the ball valve.

All help is appreciated to say the least.

John

Waterit
06-22-2008, 01:13 PM
I much rather look for keeping pressure switch controls in place, because they protect against closed zone valves. There is really no excuse for not knowing the performance of a well, if you're taking on the job of designing/installing a sprinkler system.

Agreed on the well performance. Have to know your supply to be able to engineer properly.

We prefer straight pump-start with a pressure relief valve adjusted to the smallest zone for the protection factor.

Wet_Boots
06-22-2008, 01:32 PM
I have trouble seeing a 10 series Goulds pumping 20 gpm. Something is messed up here. Are you obtaining steady-state measurements? No cycling? At 100 feet drawdown depth, a 1-1/2 HP 10-series Goulds should be putting out some serious pressure.

Is this an irrigation-only well? (we should not have to ask twice)

jcom
06-22-2008, 02:12 PM
Yes, this is an irrigation only well. High iron in our wells here.

The flow and psi will hold steady if this is the steady state you refer to WB.

It sure seems to me to be messed up. 32 psi. is not going to get it done in my opinion. And 6 gpm and 40 psi is out of the question to irrigate this approx. 1 acre layout.

Flow testing does not appear to be rocket science. Restrict the flow to get the desired psi. and design from there with the flow you have. But this just doesn't compute on this well.

Again, the contactor on the pressure switch was engaged all the time we were messing with the ball valve.

Pressure was at 48 psi. when all is closed and of course the pump won't engage until the psi. drops to 30. But when it kicked in, it would not build psi. to allow it to kick out as long as we had the ball valve open.

Thanks to all for the patience. I hope to have a little hair left when we figure this one out.

John

jcom
06-22-2008, 02:15 PM
As I mentioned before, we installed a Goulds 1 hp. 10 series in a river last week and it really puts out. It is on a pump relay with a 70 psi pressure relief valve in place. Zoned for 17-18 gpm and absolutely no problem in that regard.

Wet_Boots
06-22-2008, 02:34 PM
Sounds like you might actually be able to raise the pressure switch settings, and see a point where the pump actually can't build enough pressure to trip the switch. That would not be consistent with a 1-1/2 HP 10 series pump at 100 feet. That specific pump is made for deeper settings, so double check as to what is really there.

The other concern is that the well is a low producer, and is running dry. That is what takes time to ascertain, and you can actually wind up running at very low flows, in order to run without the well running dry.

AI Inc
06-22-2008, 02:37 PM
Sounds like you might actually be able to raise the pressure switch settings, and see a point where the pump actually can't build enough pressure to trip the switch. That would not be consistent with a 1-1/2 HP 10 series pump at 100 feet. That specific pump is made for deeper settings, so double check as to what is really there.

The other concern is that the well is a low producer, and is running dry. That is what takes time to ascertain, and you can actually wind up running at very low flows, in order to run without the well running dry.

If that is the case use multiple programs to water different sections at different times, days ect.

Wet_Boots
06-22-2008, 02:46 PM
If that is the case use multiple programs to water different sections at different times, days ect.Nahh, something's hinky here. Did the test show a sustainable flow of 20 gpm with 33 psi at the tank? No drifting down of flow and/or pressure? I'm thinking a less powerful pump might be in place. If you can verify a constant flow, then it will be possible to install a different pump, and deliver that flow at a higher pressure.

Or you could just install several acres of Maxipaws. :p

AI Inc
06-22-2008, 02:52 PM
Open ball valve to allow pressure to drop enought to start pump. Shut ball valve and count how long it takes to get to cut off pressure. If it is more then a minute , you have water availability issues.

AI Inc
06-22-2008, 02:53 PM
Nahh, something's hinky here. Did the test show a sustainable flow of 20 gpm with 33 psi at the tank? No drifting down of flow and/or pressure? I'm thinking a less powerful pump might be in place. If you can verify a constant flow, then it will be possible to install a different pump, and deliver that flow at a higher pressure.

Or you could just install several acres of Maxipaws. :p

BTW , Tommy lee Jones would bust ya balls for saying hinky.lol

Wet_Boots
06-22-2008, 03:01 PM
I'm kind of wondering where the choice of a 10GS10 in a river came from, given that it would have a shutoff pressure higher than 160 psi.

jcom
06-22-2008, 06:14 PM
The pump seemed to be able to hold about 32 psi and was flowing at 20 gpm. We ascertained that the pump remained running while testing.

When we shut the ball valve at this time, it takes 45 seconds to reach 47-48 psi where it kicks off.

John

Wet_Boots
06-22-2008, 07:37 PM
If you look at Goulds' pump charts, you will see that nowhere do they give flows that are twice the series number. 10 series pumps show maybe 16-17 gpm tops. Think of what that river pump you installed would do, if you choked off the flow. Serious pressure. (hope you got a good relief valve on that system)

jcom
06-22-2008, 10:35 PM
WB- We put in a 70 psi relief valve.

jcom
06-22-2008, 10:37 PM
I am a believer that corporation flow rates are greatly underrated for obvious liability reasons.

jcom
06-22-2008, 10:40 PM
But we looked at the Goulds literature for our river install and zoned accordingly. I believe we have a lot of extra capacity on that system.

But this well system is a whole different animal.

Well driller does not know which way to turn right now. Our psi and flow are something he has not encountered as yet. He has been doing this for 30 years.

John

Wet_Boots
06-22-2008, 10:56 PM
I am a believer that corporation flow rates are greatly underrated for obvious liability reasons.You probably don't want to live by those words - these curves are fairly consistent, and the efficiencies are what they claim. Seen any V-8 pickups getting 35 mpg? So much energy moves so much water.

Just have your measurements in order, so the well guy can work it from there. If there is a 10GS15 pump in your 100 foot well, it is probably defective.

On the river pump, you would generally look for something with less stages, and get a bit more water, and a lower top pressure, which is nice if you want to avoid blown poly pipes.

jcom
06-22-2008, 11:30 PM
Thanks, WB,

Your insight is greatly appreciated. Again, you surely have forgotten more than I will ever learn.

My numbers as to the flow and psi are solid and I just ended a visit with the driller. He also does not understand why this pump will not give us a lot more psi with the water he maintains is available. He told me the pump is a 10 series and 1 1/2 hp.

He told me the well is 160' deep and the pump is at the 120' level. He maintains there is a very ample amount of water available.

To say the least, our meeting tomorrow will teach us all a lot.

Thanks again, WB, for the insight.

10 series 1 hp. is standard for river installs here for average residential property for what it is worth.

John

Wet_Boots
06-23-2008, 10:11 AM
Submersibles with less stages don't have any practical deep-well application, so they wouldn't have been in stock for the first river-pump guy to set the trend with. No big deal, as long as the relief valve is large/reliable enough to handle the flow. Strictly for the money, you have a lower list price for a 13GS07, about the same flow at 60 psi, and a shutoff pressure under 100 psi. Or, sticking with 1 HP pumps, a 25GS10 will flow about 24 gpm at 60 psi.

jcom
06-23-2008, 01:50 PM
I'll give one of those you mentioned a try on my next river pump, WB.

Thanks again for the assist.

John

jcom
06-23-2008, 11:21 PM
We turned up the pressure switch to 50-70 psi. and ran the pump.

If we allowed the pressure tank to fill and regulated the output to 14 gpm, the pump would hold at 50 psi. In theory, this would allow us to irrigate up to the 300' ft. range we are looking for.

We are going to hook up a surface zone with 14 gpm tomorrow before we bury anything. Just to see how the pump and tank will function. Pump installers think that if this will not work, their next option would be to remove the pressure tank. If that did not allow the system to work, they would opt for a constant pressure pump, (whatever that is?) and they feel that would work for sure but the owner would have to spend a lot more money. Go figure.

John

Wet_Boots
06-23-2008, 11:28 PM
We turned up the pressure switch to 50-70 psi. and ran the pump.

If we allowed the pressure tank to fill and regulated the output to 14 gpm, the pump would hold at 50 psi. In theory, this would allow us to irrigate up to the 300' ft. range we are looking for.

We are going to hook up a surface zone with 14 gpm tomorrow before we bury anything. Just to see how the pump and tank will function. Pump installers think that if this will not work, their next option would be to remove the pressure tank. If that did not allow the system to work, they would opt for a constant pressure pump, (whatever that is?) and they feel that would work for sure but the owner would have to spend a lot more money. Go figure.

John

Seems to be somewhat at odds with your earlier testing
Just got back from the well and did some more testing so that some more info might be useful.

We made sure that the pump remained running and then did the flow test. It will maintain about 32 psi. after closing down the 1" ball valve enough and still have decent flow. Again, in the 20 gpm area. If we shut the ball valve further to gain 40 psi., the flow drops off below 6 as I stated before.

Valveman
06-24-2008, 10:00 AM
If a regular pump isn't working then a "constant pressure pump" won't help a thing. You would just be spending a lot of extra money to get something that is completely unreliable. Removing the pressure tank should not make any difference either. The pump is either working or it isn't, and removing the tank won't change a thing.

Northernliving
06-29-2008, 03:12 PM
Hi Guys,

I'm in the design phase of my irrigation system and would like to know more about the Stop Cycle Valve. Seems like sensible addition to a system with a well/pump. My well is about 100t deep with a 2hp submersible pump (I had them oversize the pump and tank when I had the house built anticipating an irrigation system). The well was rated at 30GPM when it was drilled. I’m assuming that the CSV needs to go in the well and that the extra water that is unused is exhausted back in the well. Is this correct?

Thanks for your help. I really appreciate all that you’ve contributed to this site! I’ve been reading all day! I’ve rebuilt other system in houses that I’ve owned, but this is the first new installation that I’ve done. I want to do this right, so I’m sure I’ll have some more questions!

Wet_Boots
06-29-2008, 03:22 PM
There isn't any dumping of water - the valve behaves like a pressure regulator, and restricts the flow when the outlet pressure reaches the setpoint, so that the pressure switch doesn't shut off the pump while the sprinkler system is operating.

Northernliving
06-29-2008, 04:29 PM
Thanks for the quick reply! So do you just build massive pressure behind the CSV? Isn't that bad for the pump or does the pump have some kind of relief valve?

So if this there is no discharge, the CSV can go in the basement between the pump and the tank. Correct?

Wet_Boots
06-29-2008, 05:26 PM
Just how 'massive' a pressure depends on your flow and your pump. The CSV can't be completely off, so there's enough flow to avoid disaster.

AI Inc
06-30-2008, 06:50 AM
We turned up the pressure switch to 50-70 psi. and ran the pump.

If we allowed the pressure tank to fill and regulated the output to 14 gpm, the pump would hold at 50 psi. In theory, this would allow us to irrigate up to the 300' ft. range we are looking for.

We are going to hook up a surface zone with 14 gpm tomorrow before we bury anything. Just to see how the pump and tank will function. Pump installers think that if this will not work, their next option would be to remove the pressure tank. If that did not allow the system to work, they would opt for a constant pressure pump, (whatever that is?) and they feel that would work for sure but the owner would have to spend a lot more money. Go figure.

John

Before you yank the tank , bypass your pressure switch by moving your wires from the outside ( line) to sit on top of thres in the middle ( load)

jcom
06-30-2008, 02:40 PM
We hooked up a zone to the unit and we can hold 14 gpm at 50 psi indefinitely or close to it. As soon as we go over 14 1/2 gpm the psi drops continuously.

Again, after we make sure the tank is full and then do our testing, the above zoning will work for us. We will zone to the 11-12 gpm once we get out to the 300' foot range.

Thanks for all the inputs!

John

Wet_Boots
06-30-2008, 02:56 PM
Did you run a test at your proposed 11-12 gpm? What kind of pressure did you have?

jcom
06-30-2008, 04:12 PM
WB-

We did not run a test to check our psi. but my pressure loss should not exceed 18 psi. at that flow so methinks it should be o.k..

Value your opinions so please opine.

We will begin install tomorrow if schedule holds.

John

jcom
07-15-2008, 11:31 PM
Just an update for the gurus who are dying to know what happened after all the snafus and such.

We zoned as said for 14 closest to the pump and 12 at the furthest zones. All work great and the psi will hold in the 45-50 range depending on the zone running.

Customer is happy, and therefore so are we.

Many thanks for all the help. Our first install with a pressure tank taught us a lot. (Let the pressure tank fill before flow test would be a no brainer for the gurus but an omission on our first flow test!)

Again, thanks,

John:walking:

Tom Tom
08-12-2009, 04:39 PM
Just an update for the gurus who are dying to know what happened after all the snafus and such.

We zoned as said for 14 closest to the pump and 12 at the furthest zones. All work great and the psi will hold in the 45-50 range depending on the zone running.

Customer is happy, and therefore so are we.

Many thanks for all the help. Our first install with a pressure tank taught us a lot. (Let the pressure tank fill before flow test would be a no brainer for the gurus but an omission on our first flow test!)

Again, thanks,

John:walking:



How is the system running a year later?

Did you ever use a cycle stop valve and/or what setting did you set the pressure switch at?

Does the pump cycle while the irrigation system is running?

Mike Leary
08-12-2009, 05:00 PM
Does the pump cycle while the irrigation system is running?

If any of you guys think you have pump problems, I'll bring our logger kit when we come down. :drinkup:

Waterit
08-12-2009, 05:57 PM
If any of you guys think you have pump problems, I'll bring our logger kit when we come down. :drinkup:

::::heads to store to stock up on merlot and brisket::::

jcom
08-13-2009, 09:23 AM
Customers have no problems with system at all this year. Happy campers.

The pump does not cycle when the system runs. Pressure switch is set at 70/50 and will hold during the run times.

John