Hunter rotor sprinkler heads throw a rotating stream rather than a fixed spray, which means one head covers far more ground than a spray nozzle. Fewer heads, less pipe, fewer fittings. That’s why rotors are the default for lawns bigger than a courtyard.
This guide covers which Hunter rotor suits which size lawn, how to pick a nozzle, and how to set the arc and radius once it’s in.
Which Hunter rotor sprinklers do I need?
Choose by throw distance first. Measure the widest point of the area and pick a rotor that reaches across it, because heads need to throw far enough to reach each other.
| Model | Radius | Best for |
|---|---|---|
| SRM | 4.0 – 9.4 m | Small lawns, and filling in beside larger rotors |
| PGJ | 4.3 – 7.3 m | Narrow lawns and tight domestic zones |
| PGP Ultra | 7.3 – 14.3 m | Most home lawns. The one people mean by “a Hunter rotor” |
| I-20 | 7.3 – 14.3 m | Commercial and heavy-use turf |
| I-40 | 12.2 – 21.3 m | Sports fields, large open turf |
Hunter PGP Ultra — the one most people want
The best-selling gear-driven rotor in the world, and the right answer for most Australian home lawns. Adjustable from 50° to 360°, so one model does corners, sides and full circles rather than you stocking three.
Two features earn their keep. The drive is non-strippable, so if a kid or a mower spins the turret it doesn’t destroy the gears. And automatic arc return means that if the turret does get turned, it goes back to the arc you set instead of watering the driveway until you notice.
It comes with a rack of nozzles, so you set the throw distance by nozzle choice rather than buying a different sprinkler.
SRM and PGJ — when the PGP is too much
A PGP throwing 12 m into a 6 m lawn wastes water on the fence. The SRM is Hunter’s shortest-range rotor and is designed to work alongside larger rotors on the same zone, so you can cover a big area and a small one together without splitting the zone.
I-20 and I-40 — commercial
The I-20 is built for sites that take a beating: parks, schools, sports grounds. It adds FloStop, which lets you shut off water at one head while the system is running, so you can change a nozzle without turning off the zone. The I-40 steps up again for large open turf.
Rotors or MP Rotators?
A fair question, since both rotate. Rotors are gear-driven sprinklers with their own body. MP Rotators are nozzles that fit a spray body and throw 2.5 to 9.1 m.
Rough rule: under about 9 m across, MP Rotators on spray bodies give better uniformity and lower precipitation rates. Over that, rotors cover the ground with fewer heads and less pipe. Between the two, either works and it usually comes down to what’s already in the ground.
Choosing a nozzle
The rotor sets the body; the nozzle sets the distance and the flow. Every PGP Ultra ships with a rack of them.
Two things worth knowing. Low-angle nozzles throw at a flatter trajectory and are the answer on windy sites or where the spray would hit a fence or a window. And matched precipitation matters: heads on the same zone should apply water at a similar rate, or one part of the lawn gets soaked while another stays dry. Hunter’s nozzle charts give you the rate for each nozzle at each pressure.
If in doubt, size the nozzle so heads reach each other. Head-to-head coverage is the single biggest factor in whether a lawn comes up evenly.
Adjusting a Hunter rotor
Setting the arc
Rotors come preset to about 180°. The right stop is fixed and doesn’t change; you set the arc by moving the left stop.
- Rotate the turret anticlockwise to the left stop by hand to finish any part-cycle.
- Rotate it clockwise to the right stop and hold it there.
- Put the plastic key end of the Hunter wrench into the adjustment socket.
- Turn clockwise to increase the arc, anticlockwise to decrease. Each full turn changes it by 90°.
It will ratchet when it reaches full circle. That’s the stop, not a fault.
Setting the radius
The radius screw sits on top, beside the nozzle. Turning it in cuts the throw back, by up to about 25%. Use it to stop a head watering a path, not to correct a nozzle that’s the wrong size in the first place.
You’ll need a Hunter adjustment wrench for the arc. A 3 mm hex key will do the radius screw at a pinch, but not the arc, and we don’t stock the wrench.
Common problems
The head won’t pop up. Usually pressure. Too many heads running on one zone drops the pressure below what the rotor needs to lift and turn. Count the heads on the zone against your flow rate.
It pops up but doesn’t rotate. Grit in the drive. Rotors have a filter screen under the nozzle; pull the riser, take the nozzle out and flush the line.
It won’t retract. The wiper seal has gone or there’s debris on the riser. On a PGP that’s a body replacement rather than a repair.
Water pooling at the lowest head after shutdown. That’s low head drainage, not a fault in the sprinkler. The line is emptying through the bottom head. A check valve stops it.
Buying in Australia
We’re an authorised Hunter stockist and we sell nothing else. Every rotor above is held in stock here, not ordered in, and dispatched the same day.
Not sure which model or nozzle you need? Send us the dimensions of the area and your tap pressure and we’ll tell you what suits.
