How to adjust a Hunter MP Rotator (without ruining the spray pattern)
Hunter's MP Rotator nozzles screw onto a standard spray body and replace fixed-pattern fan nozzles with multi-stream, rotating water delivery. That design drove the matched-precipitation revolution in residential and commercial irrigation. Out of the box every MP Rotator is preset to its center arc (often 180°) and full radius. Almost every install needs at least an arc adjustment; many need a radius dial-back too.
This guide walks the adjustment process for the four current MP families (MP800SR, MP1000, MP2000, MP3000) plus the MP Corner nozzle, using Hunter's official adjustment tool.
If you're shopping for the nozzles themselves, browse the full lineup on the Rotary Nozzles category page; every in-stock MP Rotator on Total Sprinkler is listed there.
You'll need
- The MP Rotator nozzle, screwed onto a working spray body that's pressurized (run the zone while you adjust).
- The Hunter MP Rotator Adjustment Tool (small black tool with a forked end and a key). The metal Hunter rotor adjustment tool (172000SP) also works.
- A general idea of the arc you want (e.g. 90° for a corner, 180° for an edge, 360° for an island).
Three adjustments, in this order
Set arc first, radius last.
The MP Rotator has three independent adjustments and the order matters. Doing it backwards means re-doing it.
1. Set the arc (the angle the nozzle sweeps)
Hold the nozzle's outer ring (the part with the printed arc markings) and rotate it until the left edge of the spray hits where you want the left boundary of the watered area. That side is now fixed. Then turn the inner adjustment ring with the forked end of the adjustment tool (clockwise to widen the arc, counter-clockwise to narrow it) until the right edge of the spray hits the right boundary.
The arc range depends on the model:
- MP800SR, MP1000, MP2000, MP3000 adjustable-arc models: 90° to 210°.
- 360° fixed-circle models (any "360°" SKU like HUN-58-1203): no arc adjustment, since they water a full circle by design.
- MP Corner (HUN-58-1212): 45° to 105°, purpose-built for tight corner geometry.
2. Confirm the rotation direction
Stand behind the nozzle and watch which way the streams sweep. If you need the opposite direction, you'll need to swap to the matched left-rotation MP nozzle. Hunter manufactures most arcs in both rotations, and Total Sprinkler stocks both rotation variants; see the Rotary Nozzles category for the full list.
3. Dial in the radius (the distance the streams reach)
Insert the key end of the adjustment tool into the small port on top of the nozzle (look for the slot marked with a flat-head screwdriver symbol). Turn clockwise to reduce the radius (up to about 25% pullback from full); counter-clockwise to restore full radius. The MP Rotator family is engineered so that radius reduction preserves matched precipitation — you can dial down a 30' nozzle to 24' without creating dry spots. Don't push beyond the documented 25% reduction; past that point precipitation uniformity degrades and you'll get dry strips.
Pressure matters: pair with PRS40, not PRS30.
The MP Rotator design point is 40 PSI dynamic at the nozzle; the full operating range is 30–55 PSI. PRS40 spray bodies regulate to 40 PSI, which is why PRS40 + MP Rotator is the canonical pairing, and Hunter built the PRS40 specifically for the MP Rotator.
PRS30 bodies regulate to 30 PSI, the low end of the MP Rotator's operating range; reserve PRS30 for the MP800SR family at its 6' minimum radius. For all other MP Rotator zones, use a PRS40 spray body. For the full PRS30 vs PRS40 decision tree, see our PRS30 vs PRS40 comparison guide.
Which MP Rotator family do I have?
typical 10–12' residential zone
Five MP Rotator nozzle families cover the residential and light-commercial range. Pick by the radius your zone needs:
| Family | Radius (ft) | Arc | Best for | Example SKU |
|---|---|---|---|---|
| MP800SR (short-radius) | 6'–12' | 90°–210° or 360° | Tight strips, narrow side yards, mixed-head fix-up | HUN-58-1553 90°–210° female thread |
| MP1000 | 10'–12' (extended to 15') | 90°–210° or 360° | Standard small residential zones | HUN-58-0015 10–12' female thread |
| MP2000 | 13'–21' | 90°–210° or 360° | Most mid-sized residential zones | HUN-58-1204 MP2000 male thread |
| MP3000 | 22'–30' | 90°–210° or 360° | Large lawns, light commercial | HUN-58-0017 16–20' female, plus 360° variants |
| MP Corner | 8'–15' | 45°–105° | Tight corners where a wider arc would overspray hardscape | HUN-58-1212 |
All in-stock MP Rotators on Total Sprinkler are on the Rotary Nozzles category page. If you don't see the rotation, arc, or radius you need, contact us. We stock the male-thread and 360° variants behind the most common SKUs.
Common mistakes that ruin an MP Rotator
- Adjusting with the zone off. You can't see where the spray goes. Run the zone (or have a helper turn it on at the controller) while you adjust.
- Forcing the inner ring past its arc limit. The mechanism stops at 90° on one end and 210° on the other. If you feel resistance, you've hit the stop. Back off.
- Pairing MP Rotators with PRS30 bodies (or unregulated bodies on high-static-pressure mains). Below 30 PSI or above 55 PSI, MP Rotator throw shortens and the stream profile gets ragged. Use PRS40 spray bodies for any MP Rotator zone above the MP800SR's 6' minimum radius.
- Mixing MP Rotators and fixed-spray nozzles in the same zone. The MP Rotator's precipitation rate (about 0.4 in/hr) is roughly a third of a fixed-spray nozzle's. A mixed zone will under-water the rotator section and over-water the spray section. Convert the whole zone or none of it.
- Dialing radius past 25% reduction. Matched precipitation breaks down past that point. If you need more pullback, swap to the next-smaller family (MP3000 → MP2000, MP2000 → MP1000).
Keep going
If you're tuning up the rest of your system:
- Full Rotary Nozzles category — replacement MP Rotators in every arc and radius.
- Spray and Rotor Tools category — adjustment keys, riser tools, and replacement parts.
- PRS30 vs PRS40 comparison guide — which body to use for MP Rotator zones, with the MP800SR edge case explained.
- Pressure-Regulated (PRS) Spray Heads — the bodies that go under MP Rotators.
