[mnikon]

Hello all! I am new to the forum here but have been following for quite some time. I am currently in the process of updating my existing irrigation system from Hunter PGP ultra rotors to MP rotators. The main issue I seem to be having is system pressure. I have read through quite a bit of the irrigation tutorials website but still can't seem to figure out my issue. My home provides 11gpm @ 50psi. However every single rotor zone seems to only operate @ 20psi. While 20psi is low for the MP rotators the 3000s seem to work fine in the front lawn where my heads are only spaced @ 20ft. I am however 2nd guessing the swap in my backyard as the heads are spaced closer to 25-30ft. My main question is what in the world could be eating up 30psi from the source to the heads? I would prefer to operate these at their recommended 40psi. Any help would be greatly appreciated!

 

[mnikon]

A few more notes i forgot to mention. From what I can tell all valves are 1", all laterals are 1" and all sprinklers connect to 1/2" funny pipe from the laterals.

 

[Ecks from Tex]

Welcome! I have questions.....

My home provides 11gpm @ 50psi.

How do you know this and at what point in your system was it measured?

every single rotor zone seems to only operate @ 20psi.

How are you measuring this? Are you measuring each head or what exactly are you doing to make this determination?

 

[g-man]

Welcome to TLF.

How are you measuring the psi at the heads? When swapping to the mp, do you plan to swap the bodies to the regulated ones?

Do the valves have flow controls?

 

[mnikon]

The GPM was done based on pipe size from irrigation tutorials. I also confirmed with a bucket test. The system pressure was taken from the spigot on the irrigation mainline. Each head was tested by placing the gauge inline @ each head in the zone.

 

[mnikon]

Welcome to TLF.

How are you measuring the psi at the heads? When swapping to the mp, do you plan to swap the bodies to the regulated ones?

Do the valves have flow controls?

As of right now the areas with MPs are just using standard Hunter Pro Spray bodies.

 

[Ecks from Tex]

The GPM was done based on pipe size from irrigation tutorials. I also confirmed with a bucket test. The system pressure was taken from the spigot on the irrigation mainline. Each head was tested by placing the gauge inline @ each head in the zone.

If I'm in your shoes, my first concern would be that the GPM from my house is not accurate. Irrigation tutorials also cautions against the bucket test. Normally I don't think it would matter if you weren't having an issue, but I think in your situation you've got to play detective, so to speak, and go back to the source. That probably requires you calling your water provider to get supply information (I have done this as well) and then figuring out how to get the most accurate reading at your house.

My worry is that you don't have the pressure you need. Pressure regulated bodies and flow control valves may be in your future, but before you go fixing problems you aren't sure you have, I'd get the most accurate numbers I can.

 

[g-man]

I would do the meter test. Open the meter and record the number. Trigger irrigation and run it for 10mim (without anything else in the house running). Record the second number and calculate your gpm that way.

 

[mnikon]

The GPM was done based on pipe size from irrigation tutorials. I also confirmed with a bucket test. The system pressure was taken from the spigot on the irrigation mainline. Each head was tested by placing the gauge inline @ each head in the zone.

If I'm in your shoes, my first concern would be that the GPM from my house is not accurate. Irrigation tutorials also cautions against the bucket test. Normally I don't think it would matter if you weren't having an issue, but I think in your situation you've got to play detective, so to speak, and go back to the source. That probably requires you calling your water provider to get supply information (I have done this as well) and then figuring out how to get the most accurate reading at your house.

My worry is that you don't have the pressure you need. Pressure regulated bodies and flow control valves may be in your future, but before you go fixing problems you aren't sure you have, I'd get the most accurate numbers I can.

I was afraid of this. I moved into this home with the irrigation already installed. We have always had pressure issues in the house if the irrigation is running. Mostly noticed when
I shower in the mornings before work. The more and more research I do the more and more im finding whoever did my irrigation didnt know what they were doing totally. Including every rotor being nozzled exactly the same. This was the main reason why I started digging into this was the uneven watering and dry spots I was getting from my system. The old nozzles were WELL over 11GPM per zone. I have renozzled everything to get approptiate coverage but the pressure issues remain. I will be calling my Water company asap to fogure out what numbers they claim to be offering. I will post back with my findings. Thanks!

 

[mnikon]

I would do the meter test. Open the meter and record the number. Trigger irrigation and run it for 10mim (without anything else in the house running). Record the second number and calculate your gpm that way.

This is a great suggestion! Funny how one can overlook things. For clarification when you say "Open the meter" are you refering to a spigot? Or something else?

 

[mnikon]

A little more info. on my system......I have 8 zones total. Zone 1 is 6 MP rotator SRs, zone 2 is 4 MP rotator 3000s (1 does 360), zone 3 is 5 MP rotator 3000s, zone 4 is 5 PGP Ultras, zone 5 is 5 PGP ultras (2 heads do 360s), zone 6 is 6 PGP ultras, zone 7 is 6 MP rotator side strips, zone 8 is 6 MP rotator side strips. Zones 1,7,8 do 40psi exactly so tbose are good. Im assuming from the lower GPM. Which seems ultra low at around 2-3GPM only. Keep in mind this entire system was existing and I'm trying to do the best with what I was given.

 

[Ware]

This is a great suggestion! Funny how one can overlook things. For clarification when you say "Open the meter" are you refering to a spigot? Or something else?

No I think he's talking about opening the water meter box and getting readings from the dial on the meter. Around here you would need a "key" for the meter box. Also note that some dials read in cubic feet, so you would convert to gallons (1 cubic foot = 7.48 gallons).

 

[g-man]

Zone 6 and 8 have 6 pgp and they are all working? Have you calculated the theoretical GPM for those zones?

Open the meter means going to the yard and finding the metal top that the water company has the water meter at. The meter has the CCF of water measurements.

 

[Ware]

Note 1 CCF is one hundred cubic feet, or 748 gallons. Moral of the story is just pay attention to the units on the meter face. :thumbsup:

 

[Ecks from Tex]

The GPM was done based on pipe size from irrigation tutorials. I also confirmed with a bucket test. The system pressure was taken from the spigot on the irrigation mainline. Each head was tested by placing the gauge inline @ each head in the zone.

If I'm in your shoes, my first concern would be that the GPM from my house is not accurate. Irrigation tutorials also cautions against the bucket test. Normally I don't think it would matter if you weren't having an issue, but I think in your situation you've got to play detective, so to speak, and go back to the source. That probably requires you calling your water provider to get supply information (I have done this as well) and then figuring out how to get the most accurate reading at your house.

My worry is that you don't have the pressure you need. Pressure regulated bodies and flow control valves may be in your future, but before you go fixing problems you aren't sure you have, I'd get the most accurate numbers I can.

I was afraid of this. I moved into this home with the irrigation already installed. We have always had pressure issues in the house if the irrigation is running. Mostly noticed when
I shower in the mornings before work. The more and more research I do the more and more im finding whoever did my irrigation didnt know what they were doing totally. Including every rotor being nozzled exactly the same. This was the main reason why I started digging into this was the uneven watering and dry spots I was getting from my system. The old nozzles were WELL over 11GPM per zone. I have renozzled everything to get approptiate coverage but the pressure issues remain. I will be calling my Water company asap to fogure out what numbers they claim to be offering. I will post back with my findings. Thanks!

No worries dude even if that's the case it's a problem that can be lessened and you can DIY with a little patience. I don't have a pressure problem but I definitely have/had a coverage problem so I understand how frustrating it can get trying to solve. Gman gave you a good measuring method so just keep troubleshooting.

 

[mnikon]

Zone 6 and 8 have 6 pgp and they are all working? Have you calculated the theoretical GPM for those zones?

Open the meter means going to the yard and finding the metal top that the water company has the water meter at. The meter has the CCF of water measurements.

Zone 6 is the only zone with 6 PGPs. Yes they work but only @ 20psi. Zone 8 is 6 MP rotator side strips. Zones 1,7,8 all run fine @ 40psi. Im assuming from the lower gpm consumed by the side strips and SRs. It's only zones where PGPs were initially installed I'm getting 20psi. Including the front zones 2 and 3 where I have swapped PGPs out for MP rotator 3000s. Thank you for the clarification on opening the meter. I will see what I can do with this as I'm in MN and our meters are in the basement to prevent freeze. Mine is burried in a closet unfortunately. May be messy to open the meter up. The theoretical GPM for zones 7 and 8 is only 2.6GPM😔. Theoretical for zone 1 is only 2.3GPM. That seems silly low.

 

[g-man]

Wait the water company goes to your basement every month to bill you? I don't think the meter could be in the basement.

There is a relationship between gpm and pressure drop. As you flow more water it will drop more pressure (more friction with the pipes). Switch to MP will be a positive thing to do since they are lower flow.

 

[mnikon]

Wait the water company goes to your basement every month to bill you? I don't think the meter could be in the basement.

There is a relationship between gpm and pressure drop. As you flow more water it will drop more pressure (more friction with the pipes). Switch to MP will be a positive thing to do since they are lower flow.

Yes indeed the basement due to deep winter freezes in MN. They have a wireless transmitter connected to it so they can drive by and read your meter monthly. Cool huh?

Edit. My main issue with the rotators out back is zone 5 utilizes 2 360s and 1 270. Even with the rotators im still over my supposed 11gpm which i think weve determined is completely false lmao. Also the heads are spaced further than the front lawn so even the MP3000s @ 20psi wont give me full head to head coverage.

Edit 2 - Zone 5 theoretical GPM with MP rotators would be 10.08GPM @ 25psi. Technically shy of 11gpm but again that isnt accurate.

 

[mnikon]

Almost wondering if theres an issue with my supply line in the yard feeding the house. 2.6GPM cant be legit can it?

 

[Ecks from Tex]

Almost wondering if theres an issue with my supply line in the yard feeding the house. 2.6GPM cant be legit can it?

I'd you know how much the water co supplies you, and what your pressure is at the house, you can probably figure that out.

And you could go dig a small hole at the main and see how big the line is. I'm wondering if the installers put in a small line