As an Amazon Associate I earn from qualifying purchases. Some links on this site are affiliate links: if you buy through one, EvenParts may earn a commission at no extra cost to you. Learn more.
Robotic Cleaners

Robotic Pool Cleaner Troubleshooting

Won't climb, tangled cable, not cleaning, error lights: the checks Polaris and Maytronics list in their own manuals, in the order they list them.

As an Amazon Associate I earn from qualifying purchases. The "Search Amazon" buttons and the "Worth a look" links on this page are Amazon affiliate links; we show no prices or ratings. Facts recorded Oct 25, 2026 from the official sources linked on each section. Manufacturer pages and rules change, so check the current version and your model's manual.

Difficulty: easy user-level checks

Safety first: robots, power supplies and batteries

  • GFCI only. Polaris says its robotic cleaners plug into a GFCI outlet, and Maytronics' U.S. Dolphin LIBERTY safety sheet says the power supply must be on a GFCI-protected circuit. If a GFCI trips by itself, both say not to use the product until the problem is corrected.
  • Distance from the water. The Polaris 9350/9450/9550 manual says to keep the control unit at least 5 ft from the pool edge (U.S. National Electrical Code). Maytronics says to place the LIBERTY battery charger at least 10 ft from the pool edge and at least 4 in above the ground. No extension cords (both makers).
  • Nobody swims with the robot in the pool. Both makers say to take the cleaner out before people get in.
  • Don't open power supplies, chargers or batteries. Polaris says never to open the charging station and not to attempt repair of the cleaner, charging station or cord; Maytronics says the LIBERTY battery is non-replaceable and not to open it. Use the maker's support instead.
  • Impeller blades. Maytronics says to use the impeller safety tool and keep fingers away from the impeller and drive belt.

Sources: Polaris pool cleaners; Polaris 9350/9450/9550 owner's manual; Polaris FREEDOM owner's manual; Maytronics LIBERTY safety instructions (USA)

The question

"My robot stopped climbing, keeps tangling, leaves dirt behind or flashes an error. What do I check, and when is it time to call the maker?" The answers below come from three manuals. Follow the one for your model.

Won't climb walls (or flips over)

  • Polaris (blog): remove the filter canister and test again. If it runs properly without the canister, the canister is clogged with fine debris (algae, silt, salt); brush it gently with mild soap and rinse with a hose.
  • Polaris 9350/9450/9550 manual: full or dirty canister; or slippery walls from microscopic algae, even if the water looks clear. Polaris says to do a shock chlorination treatment and slightly reduce the pH, and not to leave the cleaner in the pool during this treatment. Check tires for wear.
  • Polaris FREEDOM manual: full or dirty canister; worn track treads; pool chemistry (speak with your pool service professional); or the cleaner is in Floor Only mode.
  • Dolphin LIBERTY manual: filter too full, debris in the impeller housing, slippery surface, algae on walls or unsuitable pH. Maytronics says to check chemical levels, adjust them and scrub the walls.

Source: Polaris blog; Polaris 9350/9450/9550 manual, 8.3; Polaris FREEDOM manual, 7.1; Dolphin LIBERTY user instructions, 11

We don't give shock or pH instructions here; follow your chemical product's label and your pool professional.

Cable keeps tangling (corded)

Polaris says the cause is usually "too much cable length in the water": "Do not unravel the entire cable length. Place only the required length of cable in the water and place the rest on the side of the pool." The cable should enter the water near the middle of the pool's length. Tangling can happen more often on the 7-day programmed cycle, so don't leave the cleaner unattended for long periods. After each cycle, unplug, remove the cleaner and untangle coils starting at the cleaner head; lay the cable straight in the sun to relax it.

Source: Polaris 9350/9450/9550 owner's manual, 6.2 and 8.3

Floats or won't stay on the bottom

Polaris (both manuals): air trapped in the housing, so take it out and re-submerge it as the manual describes; or a full or dirty canister. On the 9350/9450/9550, flashing lights during a cycle can mean the cleaner is sucking air.

Source: Polaris 9350/9450/9550 manual; Polaris FREEDOM manual

Moves but doesn't clean, or goes in circles

  • Polaris: brushes worn smooth or past the wear indicator; full or dirty canister; floating cable excessively coiled or kinked.
  • Dolphin LIBERTY: clogged filter basket; debris in the impeller housing or cover; an object stuck in tracks or wheels; or a pool surface "too glossy for this robot model."

Source: Polaris 9350/9450/9550 manual; Dolphin LIBERTY user instructions

Won't start, won't charge (cordless)

  • Dolphin LIBERTY: it's designed not to run out of the water, so place it in the pool within 30 seconds of starting. A full charge can take up to 6 hours; charge in the shade, between 43 and 95 °F, with clean charger contacts.
  • Polaris FREEDOM: if the indicator isn't green after 6+ hours of charging, clean the charging contacts on the cleaner and the station with a cloth and fresh (non-salt) water. A reset is: slide to off and hold for 20 seconds, then put it on the charging station.

Source: Dolphin LIBERTY user instructions; Polaris FREEDOM manual, 7.1–7.2

Error lights and codes: model-specific

Error codes differ by model, so only use the table in your own manual. As an example of how one table reads: on the Polaris 9450 Sport and 9550 Sport, codes 1–3 point to pump or traction-motor short circuits. Polaris's steps are to check for small debris or cable stopping the brushes, check the power-cable connector pins for corrosion or a bent pin, and turn each wheel a quarter turn at a time until rotation is smooth; if that doesn't fix it, contact Polaris Technical Support. Code 9 is "not a cleaner error" (normal end of cycle).

For flashing lights right after start, Polaris says to unplug and reconnect the floating cable at the control unit, re-submerge the cleaner, and restart a cycle. A jammed propeller or wheels: contact your retailer for a diagnostic review, then Polaris Technical Support (1-800-822-7933).

Source: Polaris 9350/9450/9550 manual, 8.3–8.4

When to stop and call the maker

Polaris's manual says anything beyond the routine cleaning and maintenance it describes must be done by a qualified pool-equipment professional. If the wear parts are fine and the troubleshooting table doesn't fix it, contact your dealer or the manufacturer: Polaris 1-800-822-7933; Maytronics U.S. 1-888-365-7446. We don't publish a robot "lifespan." See also Robotic pool cleaner replacement parts.

Source: Polaris 9350/9450/9550 manual (front-page warning); Dolphin LIBERTY user instructions (contacts)

Other brands

We haven't read Aiper or WYBOT troubleshooting manuals yet, so they aren't covered here. WYBOT's product FAQ says very dirty water can affect the robot's performance and recommends running your circulation and filtration first. WYBOT C2 FAQ

Should you DIY? / When to call a pro

Fine to DIY: emptying and rinsing filters, checking brushes and tracks for wear, untangling the cable, clearing debris from wheels, and the user-level steps in your manual.

Call the manufacturer or dealer: motor units, power supplies, chargers, batteries, damaged cords and anything else beyond "routine cleaning and maintenance" (Polaris says that work must be done by a qualified professional). Call a licensed electrician: if the outlet isn't GFCI-protected or the GFCI trips by itself.

See our full When to Call a Pro page. Follow your model's manual; this site isn't a substitute for it, and it isn't legal advice.

If your model isn't listed

The numbers on this page come from specific manufacturer documents and models. If your equipment isn't one of them, don't assume the same numbers apply: find the model number on the rating plate, open that model's manual on the manufacturer's site, or contact the manufacturer. You can also email us with the brand and model number.

Facts from the manufacturer (and where else they came from)

Where to look

Robot parts should be bought by the manufacturer's part number. These buttons cover small supplies. As an Amazon Associate I earn from qualifying purchases.

  • Small soft brush: for canister mesh, with mild soapSearch Amazon
  • Pool water test kit: to check chemistry before blaming the robotSearch Amazon