Irrigation pump sizing

[cartim]

I have a larger lot and the furthest zone (all zones are designed at 25gpm), which is about 400 feet away from the meter. The pump will be about 125 feet away from the meter. From the meter there is only 2 feet of height difference to the last zone. (400 feet away) There is about 14 GPM at around 55 psi available from the 1 inch meter.

What size pump discharge and mainline sizing should I install leading to that farthest sprinkler zone?

What is the correct size of pump that I should I install to deliver 25 gpm to all the zones especially the ones furthest away?

There are also low volume drip zones and a couple of sprinkler zones that have much lower gpm requirements. Do I need any reducer valves for this or will the pump control cut off for these lower volume zones?

Thank You for you time!

 

[Reach4]

14 GPM at around 55 psi available from the 1 inch meter.

What is the correct size of pump

If city water, why are you planning a pump? If not city water, a meter would be less usual.

 

[Sponsor]

 

[Valveman]

Like Reach says, a larger meter would give you 55 PSI at 25 GPM. I am not sure what the pressure will be when trying to such 25 GPM through a 1" meter. At 25 GPM you will loose 1.63 PSI for every 100' of 1.5" mainline. With 2' line you would only loose 0.48 PSI per 100'. Assuming the pressure at the meter will be zero when sucking 25 GPM, you will need a pump that can do 25 GPM at 55 PSI. Something like a Goulds J15S jet pump would get close. But a 25GB10 multi-stage would be better.

If every zone was exactly 25 GPM a 25 GPM pump would not cycle on/off. But when using anything smaller than 25 GPM, the pump can cycle itself to death quickly. Even using a pump start relay will cause high pressure on small zones, plus not allow the use of hydrants and hoses if needed.

Adding a Cycle Stop Valve to control the system will keep the pump from cycling as long as more than 1 GPM is being used. 25 GPM is a little much for the CSV1A, but the CSVS12550-1 will do a good job and only needs a 4.5 gallon size pressure tank. Without the CSV you could not get a pressure tank large enough to eliminate the cycling.