# Whats wrong with my design! Mp rotators



## Gilman (May 18, 2021)

Installing my in-ground system.

I have a 30' x 30' square zone that i used 4 Hunter prs40 and mp rotator 3500.
using the outdoor spigot that has 40 psi and a GPM of 6.66( 5 gallon bucket took 45sec to fill)

I'm not getting enough range at all and the pressure at the heads is dropping to 24psi.

Mp3500 need 1.28 GPM x 4 = 5.12

I checked for leaks and put new piping to be on the safe side.
I'm using blu lock 3/4"

Where is the problem here? 
Thank you


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## bernstem (Jan 16, 2018)

Sounds like not enough pressure, though it could also be low flow. Could be supply pressure is low or your pressure loss in the lines is high. What is the static pressure measured just after your water meter? What happens to the pressure after the meter in the irrigation line with the zone running? I


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## Gilman (May 18, 2021)

bernstem said:


> Sounds like not enough pressure, though it could also be low flow. Could be supply pressure is low or your pressure loss in the lines is high. What is the static pressure measured just after your water meter? What happens to the pressure after the meter in the irrigation line with the zone running? I


I'm running this out of my outdoor spigot. At the spigot its 40 psi. I have no way to test the pressure right after the meter. 
I have another zone that has 6 Mp1000 with 130ft pipe and at the last head i'm at 38psi


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## bernstem (Jan 16, 2018)

I didn't realize you were running it off the hose spigot. So the zone with MP1000s works fine? If that is the case, it might be a flow issue. Try capping one or two of the MP 3500s and see what happens with two or three heads on the zone.


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## g-man (Jun 15, 2017)

It is likely a flow and pressure issue. For the 35ft, you need 40psi at the head. With the 3/4in times the distance square to the flow, it might be too many friction losses. Plus you are already at the 40psi at the spigot, it likely is not 40psi at the head.

Splitting into two zone might help. Also using 1in from the spigot to the first head can also help.


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## Gilman (May 18, 2021)

Just did this now! The only way to get the MP3500 to work properly is by using only 2 at a time and the pressure at the head reduces to 28psi


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## Gilman (May 18, 2021)

Something to mention that the spigot is connected with a 1/2" pex! Is it better to replace it with 3/4" pex ?


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## g-man (Jun 15, 2017)

1/2 pex is like 3/8 copper. 3/4 can help.

Keep in mind that the max safe GPM on 1/2 Pex is 3gpm.

https://www.irrigationtutorials.com/gpm-psi-municipal-water-source/


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