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Tuesday, June 26th 2012, 7:52pm

Hunter Sprayer Question

A pro installed my system 7-8 years ago and left the business shortly there after. Since, I've largely ignored the system until now. I'm trying to learn the language. For sure I have many Hunter PGP rotors. I also have many sprayers. Most say 10A. I've come to find out that 10A is the nozzle and NOT the part number of the sprayer. Can someone tell me how to determine the replacement number of the sprayer. Next, how can I extend the height of the sprayer. The beds have out grown the sprayer height. There seem to be many choices for extending the sprayer, but not if I don't know the thread size. Last question, are PGP's and whatever my sprayers are, directly interchangeable?

Thanks in advance!!


Wednesday, June 27th 2012, 8:24am

First, all threads are standard, either 1/2", 3/4" or, rarely in residential, 1"
PGP = 3/4", pop-ups = 1/2"
Most nozzles are interchangeable EXCEPT there is a female thread (most used in industry:Rain Bird, Hunter, K-Rain, etc) and a male thread, usually Toro. If you match that then brand doesn't matter.Take a quick look at this article on NOZZLES. It's a short read and will tell you a lot. It will also explain the 10A marking.
To extend the height of a sprayer you can use cut off nipples.Pick the 1/2" or 3/4" size you need, cut to height. Again, pop-ups will use 1/2".
Replacement number of sprayer: not one. Everything is based on how high you want the riser to pop up: 4", 6", etc. Look at the sprinkler bodies . The distance above the body to the top of the nozzle (roughly) is your height. Then you pick a series. For example, if you wanted Rain Bird products the most popular series is the 1800. For a 4" rise you would get the 1804; 1806 for a 6" rise.

Finally, PGP and spray heads are not interchangeable. While you can get an adapter to make the threads work the precipitation rate of each is different. For example, the PGP comes with a choice of 12 nozzles. If I pick the middle, #6, my precipitation rate = about .36" per hour, depending on pressure, covering 36 to 38 feet. The largest gives 1" per hour.
If I pick the largest spray nozzle at 17' full circle my rate is about 1.6" per hour. If you mix them on the same zone you either flood one area or starve another.


Supreme Member

Posts: 309

Location: Northern New Jersey


Wednesday, June 27th 2012, 8:27am

If your sprays for the beds are 4 inch pop ups, replace with 12 inch pop ups. Or use the existing sprays and add risers - lengths of plastic pipe - cheaper fix. Home Depot will have risers that may fit, try that first as long as you don't mind the units showing while not watering.

Can you switch around sprays and PGPs IN THE SAME ZONE? You need to look at precipitation rates - that is how much water is put out to the lawn/beds. They should be similar. If you have one sprayer .5 inch/min and a rotor 1 inch per minute on same zone, problem potential.




Wednesday, June 27th 2012, 10:50am

Are Hunter MP's swapable with Hunter PGP's with mod at all?

Huge, huge thank you for your responses and informaiton!!!!!

At the risk of pushing my luck, I do have one final question. Can I unscrew a Hunter PGP and screw in a Hunter MP ith no modification of any kind? I'm reading that MP are the spiffy new upgrade for rotors.

Thanks again for the help!!!


Supreme Member

Posts: 5,330

Location: Metro NYC


Wednesday, June 27th 2012, 11:13am

No you can't - let the PGP heads be


Wednesday, June 27th 2012, 11:47am

Boots is right, though I have seen it done.
Strongly recommend against.
Everything goes back to precipitation rate.
Biggest MP Rotator: max 30', 40psi, precip rate = .40" +/-.
PGP: 30', 40 psi, precip rate = .6" to 1", IF you have a smaller nozzle (1,2 or 3) installed. Bigger nozzles = more water.

Plus inlet size reduces from 3/4" to 1/2"




Tuesday, July 17th 2012, 3:04pm

I wanted to catch you all up with my activities and perhaps give you a laugh as well.

First, many thanks for your help to date! I did successfully, reset my my PGP's, PJG's and Sprayers to their proper height. I will mention that in my area, if you want 1/2" cut off nipples, you can get them at Home Depot. If you want 1/2" union's, sorry those are at Lowes. 1/2" T's...back to HD. 1" unions for splices? Lowes. 1" guessed it, HD.

I also added some sprayers. Orbit was all HD or Lowe's carried. What crap! I'll say no more.

After the sprinkler exercise was complete I decided that some electricity at the back of my property was in order. So, I rented a trencher and off I went. It's not like I didn't realize there were water lines down 8" or so, but it turns out the original installer must have been drinking during the install! There wasn't a straight line in the whole yard. So yes, I cut pretty much all of them! I am now quite skilled at splicing 1" plastic line. <grin> And, much learning ensued.

When all is said and done, here's what I found and I'd like opinion's. It seems that 1" line is on the periphery of the yard with 3/4" line "T"-ing off for the PGP's and 1/2" for the Sprayers. If all of this is normal, my question now goes to zones, flow rate and all that. It seems that my yard is set up geographically rather than zones of grass, bed, shrubs, trees. And, unless I'm set for digging it all up (and I'm not), I'm stuck with this configuration.

For my question let's talk about my zones 4, 5 and 6. I have 5 PGP's in each zone. In zone 6 I decided I wanted to add some sprayers for the shrub and flower beds. It wasn't difficult, but I think there must be some math (that I don't know to figure out how many sprayers, PGP, etc. the zone can handle. Can someone point me to that learning?

In zone 4 and 5 I have a tree in each zone and would like to put something directly on each tree for deep watering. Hunter makes a gizmo of some kind for that. Can someone help me calculate that stuff. Likely it's the same math as above, right?

Then as part of what I'd like to add to the system (assuming the flow rate and capacity hold up) are these little micro sprayers and drippers I've seen. They seem like they just push into 1/2" line. However, it seems be a thinner line than the 1/2" line my sprayers are on. Can I somehow splice this type line into my 1/2" line?

I know if time, money and a trencher were at the ready, the idea solution would be to add more lines and zones, but I don't see that happening right now. I've got to cobble together my new needs with my old system, so any and all ideas are welcome.

Again, thank you all so much for your help!!! In spite of the cut lines, I've really enjoyed the learning and had fun doing the work.



Tuesday, July 17th 2012, 4:16pm

The math is simple but sometimes tedious.
First look at FLOW CHART . Find the one for the type pipe you are using: sch 40, class 200, etc.
Look at the chart. BEFORE YOU BOTHER READING NUMBERS, notice there is a section about the middle that is blocked off. This is the 'you shouldn't go there' section.
Designs should max at 5 feet per second. That is the area above the blocked area.
For example, look at Schedule 40.
On the left you have gallons per minute. Across the top you have pipe sizes.
Find pipe size, read down to first numbers above block.
For 1" this is your velocity, 4.44 fps and your pressure loss per 100 ft: 3.36 psi.
Now look directly to the left at the GPM column. The most water you can push safely through this pipe is 12gpm.
To figure how many heads you need on zone you add up the water used by each head and stop before you get to 12.
A 3/4" sch 40 only moves 8gpm. Not a lot of heads on an 8 gpm pipe.

"Safe" means avoiding water hammer and undue stress. People can and do exceed this all the time. Sometimes they get away with it, sometimes not. Sometimes you get a way with it for a few years then things go bad. Ya' never know.

"these little micro sprayers and drippers I've seen. They seem like they
just push into 1/2" line. However, it seems be a thinner line than the
1/2" line my sprayers are on. Can I somehow splice this type line into
my 1/2" line? "
Remember, those figure in gallons per HOUR. Your heads figure in gallons per MINUTE. If you combine drip and sprays on one zone you will either flood one area or starve the other.
What Hunter product were you talking about on trees?




Wednesday, July 18th 2012, 7:15am

It's called the Root Zone Watering System. Here's a link

Just trying to think my way out of my problem, so see if this makes sense. Since I have 1" line around the periphery of the property with valves (do they still call them manifolds?) back at the house, can I tap into the 1" line way away from the house and put in a remote controlled valve that would control either one more line with PGP's and sprayers or an entire Micro sprayer system? The thing I'm trying to avoid is digging all the way from the house/valves, to the back of the property (around 120') just to add to a valve cluster that is close to the house.

Maybe the question is, is there any limit to the number of zones that I add to my 1" line as long as only on zone runs at a time? Then, with these micro sprayers, how do I slice them into the 1" line. Is it 1" line into the valve and 1/2" line out of the valve? Is there any kind of pressure reducer needed?


Wednesday, July 18th 2012, 8:22am

You can tap into your main line anywhere.
Adding zones doesn't make much difference if you run one at at time.
Just need to make sure you have the water and pressure.

Micro sprayers do need a pressure reducer and filter. Look at drip zone assembly for an example.

Don't run a 1/2" line out of your valve. Too limiting. Use at least 3/4" You never know what you might need in the future. The price difference between 1/2" and 3/4 or 1" isn't that much.
Fittings: depending on pipe type, barbed T or PVC combo T.
I still can't visualize one aspect of your design so I'll throw a general warning in: you can tie into your main with no problem. You cannot tie into a line after a valve with another valve without trouble following.

Root zone watering. We sell the Rain Bird equivalent but I don't know anyone that actually uses one. No reason it wouldn't work but I would hesitate to put all my water on one side of the tree. Could do interesting things to the roots. If I used it I'd use multiple around the tree.

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