Flow Control on Well Head

[npalen]

How about a flow control orifice before each zone and one pressure regulator feeding the whole system? That way each zone gets the same amount of flow to it no matter how many sprinklers. This assumes that each zone uses the same amount of water. I have done what you want but on a much much much smaller scale for lubricating a machine. I used constant pressure to the system and orifices at each lube point. This made it possible to deliver precise amounts of oil everywhere.
Eric

That seems to make sense and might work.

I'm beginning to think that my problem is that the six 1" zone valves are too large and that I should have gone with 3/4" or even 1/2" size. I say this because the 10GPM that I'm trying to achieve doesn't generate enough pressure to keep all the valves closed tightly except the one that is currently energized to run a zone. When that happens there are a couple dozen sprinkler heads trying to run on 10GPM resulting in not much more than a trickle from each.

 

[npalen]

Thinking about this some more and may have come up with a solution after remembering that there is a delay setting available in the Hunter controller software, called Hydrawise, that allows for a delay between the pump starting and a zone valve opening. I'm thinking that this might let the pump build up pressure against all the valves to keep them shut while the valve, that the controller calls for, gets opened by its solenoid.

The is no check valve on the pump so the water in the output line drains back into the well each time the pump shuts off.

This system was originally set up with the six zones but controlled with manual valves since 1976 until three years ago when we installed the controller. The last two years of drought have reduced the well output to where I have had to throttle the pump output pump down.

I will plan to add the time delay mentioned above and report back here to let you guys know how it works out. I very much appreciate all your feedback.

Edit: This short video shows how the zone valves work. It takes pressure to hold the valve closed which sounds counterintuitive.

 

[steve tym]

Pressure regulator first, flow control second.

 

[steve tym]

That seems to make sense and might work.

I'm beginning to think that my problem is that the six 1" zone valves are too large and that I should have gone with 3/4" or even 1/2" size. I say this because the 10GPM that I'm trying to achieve doesn't generate enough pressure to keep all the valves closed tightly except the one that is currently energized to run a zone. When that happens there are a couple dozen sprinkler heads trying to run on 10GPM resulting in not much more than a trickle from each.

I don't think a smaller zone valve will cure that.

 

[steve tym]

Be careful dead heading the pump.
The pump may make enough pressure to blow stuff up.
The motor is water lubricated and water cooled. It needs to have water flowing past it to keep it cool.
If there is no water flowing thru the pump long enough, it will melt the guts of the pump.

 

[Egon]

For flow control use a globe valve Or a fixed/variable orfice type valve.

 

[npalen]

Be careful dead heading the pump.
The pump may make enough pressure to blow stuff up.
The motor is water lubricated and water cooled. It needs to have water flowing past it to keep it cool.
If there is no water flowing thru the pump long enough, it will melt the guts of the pump.

Good advice. I'm always careful to not knowingly deadhead the pump for more than a few seconds but, between my wife and I, we have inadvertently left it running with no outlet flow for at least a few minutes on occasion over the last 48 years. The pump has been replaced once in that timespan. I've checked the amperage draw, out of curiosity, with the pump deadheaded and its interesting that the amperage drops way down.

I started this thread asking about a better method of controlling the flow and I still want to achieve that and certainly appreciate all the suggestions. After a lot of additional thought, however, I think that I need to solve the basic problem that being throttling the flow down low enough to not overload the well has resulted in not enough initial flow and resulting pressure to hold all six zone valves shut tightly until pressure builds up in the system.

To further explain, I can start the pump then pinch the flow down to the 10 GPM with the 1" ball valve and the pressure will hold the remaining five valves shut. But, when restarting the pump and opening one valve simultaneously, the 10 GPM can't overcome the leakage letting several more of the valves not completely shut. So I'm thinking that starting the pump and delaying the valve for a couple seconds may solve my problem.

Sorry for the wordiness here, I'm impressed if you're still with me.

 

[WranglerX]

Personally I think you are beating a dead horse in trying to throttle down the output of well/pump when it would be my concept to develop well more ..... But then my experience is with a 468 foot well (though almost 400 feet of solid granite) and 13 watering zones and the household to boot, all on a pressure tank system......... And my sprinklers/zones are only operational at night (no or little household use) and about half my zones run on odd days and other half on even days.......

 

[npalen]

Personally I think you are beating a dead horse in trying to throttle down the output of well/pump when it would be my concept to develop well more ..... But then my experience is with a 468 foot well (though almost 400 feet of solid granite) and 13 watering zones and the household to boot, all on a pressure tank system......... And my sprinklers/zones are only operational at night (no or little household use) and about half my zones run on odd days and other half on even days.......

I'm interested to hear your thoughts on "develop well more".

The driller hit a rock at 31' depth back in 1976 and we called it good with a depth to water of just over 21'. I initially installed the six zones all teed together and with a manual 1/2" valve next to each of the two dozen heads. Money was tight so no controller until three years ago.

I can live with the 10GPM during the rare drought years by running 2.0 GPM nozzles but controlling the flow can be a balancing act. I think there is a reason why controller features include a set time delay between pump start and valve opening and that can or may be utilized when the allowable flow rate is low.

 

[WranglerX]

I'm interested to hear your thoughts on "develop well more".

The driller hit a rock at 31' depth back in 1976 and we called it good with a depth to water of just over 21'. I initially installed the six zones all teed together and with a manual 1/2" valve next to each of the two dozen heads. Money was tight so no controller until three years ago.

I can live with the 10GPM during the rare drought years by running 2.0 GPM nozzles but controlling the flow can be a balancing act. I think there is a reason why controller features include a set time delay between pump start and valve opening and that can or may be utilized when the allowable flow rate is low.

Gee a rock at 31 feet and driller quit?..... 31 Feet here is not even surface water...... Suggest you talk with local geologist/hydrologist and see where other local wells are and who drilled them..... Locally here a "a rock" is just something to be drilled through..... Well report at time of drilling says my 468 foot well will go 300 gallons a minute using a air lift to test well (NOTE: I have my doubts as well was drilled 1991 long before I got property) ... And I only got a copy of well report in 2008 when I bought property, but at that time (2008) well was tested at 15 GPM and no appreciable decrease in level of water.... Suggest you explore local water tables and possible adding bulk water storage (2000-3000 tank) and second pump to disturbed stored water.... With large storage you can throttle back well pump and let tank fill at a rate the will not stress well and lever of water in tank would be controlled with simple float switch....