Flow Control on Well Head

[npalen]

I have been using a 1/2HP submersible in this well since 1976 to irrigate our 1/2 acre of fescue and it has never failed to deliver at least ten GPM. We've had a couple years of drouth in NCKS and the well responds saying I can deliver the ten gallons but absolutely no more and the pump will start sucking air. The underground sprinkler system has six zones with four or five heads per zone so I've had to install 2.0 GPM nozzles and keep the pressure at no more than 40 PSI as a result.

The problem comes with the method of controlling the flow and I've been trying to do it with the 1" ball valve shown in the pic. A 1/2" ball valve would probably work better but I'm wondering if someone could recommend a better way of controlling the pressure and flow. The problem with the large 1" valve trying to control the 10 GPM is that it is just not precise enough and not enough pressure will let several of the six solenoid diaphragm valves to stay partially open resulting in some water exiting heads on several zones at once.

I'm guessing that there is a low cost pressure control valve that could be plumbed into the PVC plumbing shown and would be precise enough to maintain the 10 GPM in varying conditions such as night time as well as full sun daytime?

Edit: The black object is a canister type sand filter.

 

[steve tym]

Simple, use a gate valve. Much easier to control.
More costly, use a pressure regulator such as a watts U5B.
Or, change nozzles so every zone uses the same amount of water.

 

[WranglerX]

How are your zones controlled and how are they scheduled....And is there well recovery time between watering zones....

 

[npalen]

Simple, use a gate valve. Much easier to control.
More costly, use a pressure regulator such as a watts U5B.
Or, change nozzles so every zone uses the same amount of water.

I've tried using 1/2" gate valves over the years at each sprinkler head to control flow and found they have enough slack in them to sometimes not allow any flow the next time using after adjusting them down to, say, 2.0GPM. Ball valves actually work better as they don't have any slack like a gate valve.

I have changed nozzles in every zone in an attempt to maintain the 10GPM zone flow.

Forgot to mention that each of the six Hunter solenoid valves has an onboard flow control that can adjust the diaphragm opening but they aren't really precise enough either.

I wish it was simple.

 

[npalen]

How are your zones controlled and what are your sprinkler heads.....

Zones are controlled with a Hunter wifi enabled programmable and Hunter valves and the heads are Rainbird 5000 series rotary.

 

[npalen]

How are your zones controlled and how are they scheduled....And is there well recovery time between watering zones....

I've tried various methods, over the years, of timing the zones including recovery time but it seems to make no difference. The well will produce 10 GPM 24/7 but no more even after several hours recovery and then pumping for, maybe, ten minutes. I'm happy to have 10GPM, just need to be able to control it.

I tried this valve back in the 70's but could not control the flow as it was erratic. The 1" size is probably too large for 10GPM?

 

[LouNY]

When adjusting valves the method of adjusting needs to be consistent all the time, either closing all the way and opening a set number of turns, or opening all the way and closing some many turns. Trying to adjust by opening and closing the slack in the actuator will affect the flow.
A pressure regulator will not control flow.

 

[steve tym]

How about a flow control, like a Dole flow control?

https://www.rcworst.com/Shared/content/mfr/eaton_corp/docs/dolevalve_specifications.pdf

 

[npalen]

How about a flow control, like a Dole flow control?

https://www.rcworst.com/Shared/content/mfr/eaton_corp/docs/dolevalve_specifications.pdf

Yeah, a flow control is probably the answer and that is what I've been using, it's just not precise enough with the 1" ball valve. It gets a bit confusing thinking about how the number and nozzle sizes of the sprinklers on each zone and trying to regulate the flow. One of the zones has only two heads so I do run larger nozzles on them while the five head zones all run the 2.0 GPM nozzles.
I'm probably overthinking it, but almost seems like both a pressure and flow regulator are needed but I'm not sure which would be upstream and which downstream of each other.

 

[etpm]

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