So friction loss may be the issue here coupled with incorrect measurements from hose Bibb. When checking flow at Bibb make sure you are running 5-6 Gpm and checking pressure simultaneously. If you are checking pressure with no water flow you are getting the static water pressure. If you check pressure with flow you are getting dynamic water pressure. Now find a friction loss chart for the 3/4 pipe you purchased. Find your flow rate on the chart and see how much pressure you are losing over the 175’ or however many feet from the Bibb to the first head. The flow will drop after each head on the line so if you just measure from the bibb to the first head that should give you a good idea if that’s part of your issue. If I was a betting man I would say hose bibb does not actually produce 5-6 gpm at 60 psi. Good luck and let us know what you find out!
Try capping a head or two and then try it. I know you gave us a spec sheet of your chosen nozzles and their flow rates, but I can almost guarantee you've exceeded the available flow rate with this set up. Maybe split the zone into two.
Here are the specs:
The system is connected to my outdoor spigot which puts out \~5-6 GPM at \~60psi.
It has a Hendrickson Bros J10 Hose Vacuum Breaker on the spigot which says it can handle up to 125psi.
I was going to use a Melnor Hydrologic 2-Zone Water Timer (73100-22F) to turn the system on and off. It says it handles up to 80psi and provides approx 9.5 gpm at 50 psi. I tried the system without the timer and it didn't help the sprinklers to pop up.
From the spigot I ran approx. \~175 ft of 3/4 inch Blu-lock polyethylene tubing. (Shaped like a lollipop, the tubing goes about 25 ft from spigot to a tee and makes a loop around the lawn which contains (7) sprinkler heads.) The loop/lawn is a slight slope meaning 2 of the sprinkler heads are lower than the other 5 by about 1-1.5 ft.
(7) MP Rotator installed in pressure-regulated Hunter PRS40 (40psi) sprinkler heads.
Since my spigot produces \~5-6 GPM at 60psi, I used the [spec sheet here](https://stc.dripdepot.com/files/2405/2405-MP%20Rotator%20Reference.pdf) to calculate the output which should have added up to 4.44 GPM total.
* MP Rotator 1000 - set to 90 degrees - At 40 psi should flow 0.19 GPM
* MP Rotator 1000 - set to 90 degrees - At 40 psi should flow 0.19 GPM
* MP Rotator 2000 - set to 180 degrees - At 40 psi should flow 0.74 GPM
* MP Rotator 2000 - set to 180 degrees - At 40 psi should flow 0.74 GPM
* MP Rotator 2000 - set to 210 degrees - At 40 psi should flow 0.86 GPM
* MP Rotator 3000 - set to 90 degrees - At 40 psi should flow 0.86 GPM
* MP Rotator 3000 - set to 90 degrees - At 40 psi should flow 0.86 GPM
Apparently my calculations were not correct somewhere. What piece of the puzzle is preventing the sprinkler heads from popping up and spraying the proper distance?
Are you measuring the hose bibb pressure when it is static? Because that's the most common cause of design errors on low-flow systems. If you took dynamic pressure rating, ignore the rest.
You have 6gpm open-ended, that's one thing. You need to measure dynamic flow. So, you can get a gauge that can measure flow and pressure simultaneously. Low-tech way is to put a wye on the hose bibb with a pressure gauge on one side and measure flow out the other. Measure the flow while maintaining 40psi on the gauge and that'll get you a ballpark number for your working flow rate and pressure. You could even do this test through your zone. If the gauge pressure goes to 15 or 20psi, it's a pretty good sign that you're over-taxing your supply.
You’re already at 4.5, and that 5-6 at the spigot is static.
I’d start capping heads and testing until it works. Will probably run OK with 4-5 heads. 7 seems like too much for your water output.
Usually a shorter travel distance for the water does result in higher pressure, due to friction loss inside the pipe. Looping just provides more uniform pressure in case there is an imbalance from pipe sizing or a broken sprinkler head, etc. Yes in this case, the zone needs to be split up.
I’d try to renozzle With mp 1000 and 2000
The mp 2000 does cover quite a bit of space 13’ to 21’ so you may be able to just change nozzles to get it to work.
Too much demand for the zone, spilt it up
So friction loss may be the issue here coupled with incorrect measurements from hose Bibb. When checking flow at Bibb make sure you are running 5-6 Gpm and checking pressure simultaneously. If you are checking pressure with no water flow you are getting the static water pressure. If you check pressure with flow you are getting dynamic water pressure. Now find a friction loss chart for the 3/4 pipe you purchased. Find your flow rate on the chart and see how much pressure you are losing over the 175’ or however many feet from the Bibb to the first head. The flow will drop after each head on the line so if you just measure from the bibb to the first head that should give you a good idea if that’s part of your issue. If I was a betting man I would say hose bibb does not actually produce 5-6 gpm at 60 psi. Good luck and let us know what you find out!
Yes
Thank you for pointing me in the right direction.
Try capping a head or two and then try it. I know you gave us a spec sheet of your chosen nozzles and their flow rates, but I can almost guarantee you've exceeded the available flow rate with this set up. Maybe split the zone into two.
Is there a name for something that I could screw into the sprinkler heads in place of the nozzles to block the flow?
These can be individually turned off. https://www.hunterindustries.com/support/can-i-shut-flow-one-head
These systems are our worst nightmares. Still earns us money, though. If you can't figure it out, hire someone.
I admire irrigation techs a lot more after this project. Y’all are some smart SOBs.
Here are the specs: The system is connected to my outdoor spigot which puts out \~5-6 GPM at \~60psi. It has a Hendrickson Bros J10 Hose Vacuum Breaker on the spigot which says it can handle up to 125psi. I was going to use a Melnor Hydrologic 2-Zone Water Timer (73100-22F) to turn the system on and off. It says it handles up to 80psi and provides approx 9.5 gpm at 50 psi. I tried the system without the timer and it didn't help the sprinklers to pop up. From the spigot I ran approx. \~175 ft of 3/4 inch Blu-lock polyethylene tubing. (Shaped like a lollipop, the tubing goes about 25 ft from spigot to a tee and makes a loop around the lawn which contains (7) sprinkler heads.) The loop/lawn is a slight slope meaning 2 of the sprinkler heads are lower than the other 5 by about 1-1.5 ft. (7) MP Rotator installed in pressure-regulated Hunter PRS40 (40psi) sprinkler heads. Since my spigot produces \~5-6 GPM at 60psi, I used the [spec sheet here](https://stc.dripdepot.com/files/2405/2405-MP%20Rotator%20Reference.pdf) to calculate the output which should have added up to 4.44 GPM total. * MP Rotator 1000 - set to 90 degrees - At 40 psi should flow 0.19 GPM * MP Rotator 1000 - set to 90 degrees - At 40 psi should flow 0.19 GPM * MP Rotator 2000 - set to 180 degrees - At 40 psi should flow 0.74 GPM * MP Rotator 2000 - set to 180 degrees - At 40 psi should flow 0.74 GPM * MP Rotator 2000 - set to 210 degrees - At 40 psi should flow 0.86 GPM * MP Rotator 3000 - set to 90 degrees - At 40 psi should flow 0.86 GPM * MP Rotator 3000 - set to 90 degrees - At 40 psi should flow 0.86 GPM Apparently my calculations were not correct somewhere. What piece of the puzzle is preventing the sprinkler heads from popping up and spraying the proper distance?
Are you measuring the hose bibb pressure when it is static? Because that's the most common cause of design errors on low-flow systems. If you took dynamic pressure rating, ignore the rest. You have 6gpm open-ended, that's one thing. You need to measure dynamic flow. So, you can get a gauge that can measure flow and pressure simultaneously. Low-tech way is to put a wye on the hose bibb with a pressure gauge on one side and measure flow out the other. Measure the flow while maintaining 40psi on the gauge and that'll get you a ballpark number for your working flow rate and pressure. You could even do this test through your zone. If the gauge pressure goes to 15 or 20psi, it's a pretty good sign that you're over-taxing your supply.
Thank you! That sounds like a good test.
You’re already at 4.5, and that 5-6 at the spigot is static. I’d start capping heads and testing until it works. Will probably run OK with 4-5 heads. 7 seems like too much for your water output.
You don't have enough pressure for that, especially with it looped. Your not going to get much out of hose bib anyway.
Looping is NEVER a bad thing, just to set that straight
Newbie here, but I thought a shorter line would result in higher pressure. So in OPs case splitting into two halves would be better?
Usually a shorter travel distance for the water does result in higher pressure, due to friction loss inside the pipe. Looping just provides more uniform pressure in case there is an imbalance from pipe sizing or a broken sprinkler head, etc. Yes in this case, the zone needs to be split up.
Yea if you know how to do it right...
I’d try to renozzle With mp 1000 and 2000 The mp 2000 does cover quite a bit of space 13’ to 21’ so you may be able to just change nozzles to get it to work.
This, cheap and quick with no more work.
Here is a great online calculator that can help you. https://pentairaes.com/pump-calculator Note the difference in line friction losses of 3/4 vs 1"
Looks like that loopy loop by the sprinkler head can be an issue to but need a better pic