Polaris Vac-Sweep 380

The 380 is the top of the belt-drive Polaris line, and the most useful way to describe it is by what it is made of: the 360's drive train on the 280's plumbing.

That is not a metaphor. Put the three parts diagrams side by side and items 1 through 20 of the 380 — wheels, bearings, belts, gears, turbine, axle blocks, frame — are the same numbers as the 360. The hose, the wall fitting, the restrictor disks, the quick disconnect, the swivels and the back-up valve kit are the D-series and G-series numbers off the 280. Polaris even sells one tune-up kit, 9-100-9010, for the 380 and the 360 together, which is about as direct a statement as a parts catalog can make.

Where it sits against the 3900 Sport

Both need a booster, both run three jets, and the step up to the 3900 Sport buys four specific things: a 2½ inch vacuum inlet instead of 2¼, all-wheel PosiDrive on a stainless chain instead of belts, WideTrax tires instead of classic, and a dual-chamber bag instead of a single.

The chain is the one worth thinking about, because it changes what wears. Belts are a consumable that Polaris does not warrant and that you will replace; a chain mostly is not. Against that, the 3900 runs a tighter wheel-speed window — 30 to 36 RPM against the 380's 28 to 32 — so it is fussier to set up correctly.

Which is why ordering parts goes wrong

This is the practical consequence and it is worth putting near the top.

A pool owner with a 380 searching for a sweep hose will find results for all three cleaners, and about half the numbers will be right. Three that catch people:

• Sweep hose — the 380 takes B5, the same as a 280. The 360 takes 9-100-1011. Same shape, different part.
• Wear rings — the 380 takes eight. The 360 takes seven.
• Rebuild kit — the 380 kit is 9-100-9030, the 360 kit is 9-100-9060, and they contain different bases.

The drive-train parts really are interchangeable between a 380 and a 360. The plumbing parts really are interchangeable between a 380 and a 280. It is the middle of the machine that is shared and the ends that are not, which is exactly backward from what most people assume.

The booster pump is a second machine, and a second warranty

The 380 needs a dedicated booster pump — a Polaris PB4-60 or a universal alternative like the Pentair LA01N — running whenever the cleaner runs. That is roughly a kilowatt on top of your filter pump, and it is where the running cost of a 380 actually lives.

The printed warranty is unusually blunt about the arrangement: the booster pump is excluded from the cleaner's warranty and carries its own separate warranty. Nothing about that has changed in substance under the current statement, where the two are simply two products with two terms.

So a 380 setup is two machines, two warranty clocks and two claims — and on the evidence of what fails, the pump is the half more likely to need one, because most booster pump failures are scheduling and wiring mistakes rather than defects.

There is a startup order that goes with it: turn the filtration pump on and let it prime before the booster pump starts. A booster fed by an unprimed line is a booster running dry.

If the pool has no booster and you would rather not add one, the 360 is the same cleaner plumbed to a dedicated return line instead.

The leader hose is cut to your pool's depth

The 380 ships with 31 feet of hose in three pieces: two 10-foot white sections that are relatively hard, and a clear soft leader that attaches at the cleaner end. Sizing it is a two-part measurement, and only the first part is obvious.

Cut the leader hose to the deepest point of the pool. Not the length that looks right — the depth measurement. The leader is what lets the cleaner get down and stay down, and one cut to the wrong length is why some 380s never work the deep end properly.

Then the whole assembly has to land within 6 inches of the farthest point of the pool, longer or shorter. If it is too long, separate the hose at the center swivel and cut equal amounts off each 10-foot section — not all of it off one. If it is too short, the extra section is 9-100-3104, and it needs a swivel and two nuts to join.

Float spacing is part of the setup too: 1½ to 3 feet apart on the feed hose, 2 to 3 feet on the leader.

Tuning is by disk, not by valve

Same target as the 360 — 28 to 32 RPM, counted for one minute on the single-wheel side with the cleaner held below the water line — but a different set of controls, because there is no diverter valve on a booster line to turn.

The blue restrictor disk goes into the wall fitting at setup. From there:

• Above 32 RPM — swap the blue disk for the red, which restricts more. Still too fast, unscrew the pressure relief valve.
• Below 28 RPM — check the in-line filter screen, the baskets and the hoses for leaks, then remove the blue disk entirely.

One rule that is easy to invert: the pressure relief valve should only be adjusted when a restrictor is installed. Disk first, valve second, never the other way around.

The back-up timer that is no longer there

Worth knowing if you are buying used or working on an older machine.

Early 380s backed up on an in-head timer — a mechanism inside the cleaner body. Current ones use an in-line back-up valve in the feed hose, 30 inches from the cleaner, and where the timer used to sit there is now a part called the feed pipe and timer blank assembly, 9-100-7003. The name is a fossil of the change.

Polaris publishes a conversion kit for the older ones, and the instructions are worth reading before you buy it, because the job is more than swapping parts. It includes cutting the feed hose 30 inches from the cleaner, discarding the timer and the old feed pipe, replacing the jet retainers if they are the glued-in old style — and filing a 2-inch notch in the frame to clear the new feed pipe, if the frame is not already notched.

Filing the frame is not reversible, and the frame is the part with the five-year warranty. That is not an argument against the conversion; it is an argument for reading the sheet first.

What Polaris will not cover

Short version, because it is the same list across the pressure-side range: bags, tires, sweep hoses, sweep hose scrubbers and belts are named as wear-and-tear items and are covered by nothing. The cleaner carries a year and the frame five.

The exclusions that catch people on a 380 specifically:

• Removing the filter screen. It is in the exclusions, and on this cleaner the screen sits in an in-line filter in the hose where it is easy to forget. Polaris's troubleshooting worksheet asks how often you clean it and lists "never" as one of the options, which tells you how common that answer is.
• Freeze damage. Drain the cleaner, and drain the booster pump as well — that is a second machine with its own drain plug.
• Chemical shock with the cleaner in the pool. Take it out first.

The two SKUs

F3 is the blue and white cleaner. F3B is the Black Max, the same machine in black with black tires for a dark-bottom pool. Polaris lists it as its own SKU rather than a color choice, and the tire number changes with it — C11 instead of C-10 — so a set of white tires ordered for a Black Max will fit and will look wrong.