# Need Increased Precipitation Rate But Not Radius - How To Handle?

My system was originally set up using #4 Red nozzles (PGP-ADJ) for all rotors

I’m in the process of re-configuring to the following

• Red #4 - 90 - 0.27 in/hr
• Red #9 - 180 - 0.52 in/hr
• Red #12 - 360 - 0.99 in/hr

My issue is that at 50 psi my 180 rotors throw water further than I’d like

I’ve tried adjusting the radius screw but when I reduce it far enough, I get lots of misting

Any suggestions? Thanks

Well, that is,fairly open ended, those heads throwing father than you would like, is probably ok, usually the water at the end of the curtain is minimal, has a catchup test shown that your efficiency is low?

Sorry, should have mentioned that it’s either hitting my house or spraying on the driveway

Still working on the catch cup - was trying to get the spray patterns how I wanted them first

Trying to understand something - Hunter’s examples for ‘matched precipitation’ doesn’t seem to consider the increased radius of nozzles with higher flow

The article just says 1x flow for 90, 2x for 180, 4x for 360… except it doesn’t seem like it would be that simple since the radius is changing, right?

What they mean is that a 90,flows at 2gph, then you,180’s should flow at 4gph and your 360’w at 8gph.

This is,because a 180 has th cover 2 times the area tha a 90,does, and a 360 2x the 180.

Understood but if the radius isn’t constant, it seems that you can’t swap them in and out so easily

For instance, a #4 (34 ft) won’t overthrow as much as say a #7 (40 ft)

You have fairly old rotors if they use the red PGP nozzles. They should begin to wear out ovet time. Check if Hunter has a low angle nozzle option available for the red nozzles. How many rotors do you have? If not too many you can replace them with new PGPs that use the blue nozzles. For the new rotors they have free grey nozzle trees that are low angle. The low radius nozzles throw less further. If you are decreasing the radius by more than 25 percent try using MP Rotators that have so many radius configurations. Hope this helps a little.

Well, they were first installed about 2 1/2 years ago - not sure how long they were in the installer’s supply store

I have about 40 rotors or so - thought about the LA nozzles - might be helpful to since my area is quite windy

My rotors should accept either the Blue or Grey nozzles, right? I can put a Red in a new one, so it seems like they should?

Interesting idea about the MP rotators, will have to give them some thought

You can try, but as I recall they are not compatible. Those PGPS only have a two year warranty from date of manufacture. Personally, I would complain to the contractor because it’s been at least four years since Hunter was selling the old style rotor. The good news is Hunter is very good about standing behind their products. Find out where he bought them and tell him he sold you old stock.

How would I know if they are not compatible? Would it be as simple as it just doesn’t fit?

I just checked Hunters website. I was wrong. The blue nozzles will fit any PGP back as far as 1982. My memory sometimes fails. Sorry. So I would insert the PGP low,angle nozzles. They are grey. Look in the Hunter catalog for the correct part number. Any Hunter distributor can get or give them to you. Or call Hunters tech service group. Just make sure they don’t confuse the pgp ultra nozzles with regular pgp nozzles.

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Gotcha, thanks!

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It doesn’t seem to me that it’s possible to do what it describes (with rotors, at least)

It seems to indicate that you can have a 90, 180 and 360 rotor, all with the same radius of throw

Am I understanding this correctly?

If so, it doesn’t seem like you can turn down the higher flow nozzles’ radii to equal the 90 rotor - as you can only reduce by 25% and even then, you get misting

Well my rotors allow you to adjust the flow which doesn’t effect the radius, just the volume of water that passes,

It has to do with the nozzle selection. For example,
4.0 gpm nozzle for full circle
2.0 gpm nozzle for half circle
1.0 gpm nozzle for quarter circle.

If you turning down the radius screw you either be using low angle nozzles, MP rotators or no rotors at all.

You must be referring to the K-Rain rotors. I think they are an upgrade to the RPS.

Understood and that’s what I set out to do… however, I am having difficulty because the 180 rotor is now throwing water further and onto my driveway

What is your pressure? Perhaps go to all low angle nozzles. Check Hunters spec chart. I know irrigation is frustrating.

Pressure is 50 psi at these particular rotors

Took a look at low angle but they seem to have similar issues

For instance, if I were to use a #4 on my 90 (1.8 gpm), that would drive me to use #7 for 180 (3.5 gpm)

But then, at 50 psi, the #7 would throw 35 ft which is about 10 ft further than it needs to be

I took a look at MP Rotator and those seem like they might work better but I’d rather not have to change over

Hmmm. Those larger nozzle sizes are for large yards and larger sized pipe. Try 3.0 for full circle, 1.5 for half and .75 for smaller yard. You are seeing unusual results. I have 9 rotors in my backyard all on one zone, but it’s 4,000 square feet and I have a 1.25 inch mainline.

What’s a 0.75?

Are you suggesting that I use #1 for 90, #4 for 180 and #6 for 360?