My pool robot no longer climbs the walls
The short answer. A robot climbs the walls using the grip of its brushes and the suction that presses it against the surface. When it stops climbing, it's almost always one of these three problems: the brushes are worn and slip, the filters are full and suction has dropped, or a greasy film on the liner prevents any grip.
Also check the most obvious thing: your robot might simply be programmed in floor-only mode.
1. The brushes are worn
This is the number one cause, and the one most often ignored.
The brushes or grip bands are what catch on the wall. They wear out, flatten, harden with UV exposure, and lose their bite. A robot with worn brushes still cleans the floor very well but can no longer climb. This is exactly the symptom people describe.
How to check: turn the robot over and look at the brushes. Rounded, flattened, split, or visibly shorter bristles than originally are the diagnosis.
Run your finger over them. A new brush grips. A worn brush slips.
This is a normal wear part that is replaced, like the pads on a cleaner. It's not a breakdown.
2. The filters are full
Suction helps press the robot against the wall. Saturated filters reduce flow, and therefore grip.
Many owners clean the filters "when they remember." On a robot that is working well, they should be rinsed after every cycle, or at least as soon as they appear loaded.
A filter that looks clean to the eye can also be deeply clogged with pollen or fine particles. If rinsing doesn't restore suction, it's time to replace the cartridges, such as those for the Hayward TigerShark, AquaVac, or Pentair Prowler.
3. A greasy film on the walls
This one is surprising, and it explains cases where everything else seems correct.
Sunscreen oils, lotions, and organic residues form a thin film on the waterline and the walls. This film is slippery. No robot, even a new one, will climb a soapy wall.
The unmistakable sign: your robot climbed well in June and no longer climbs in August, after a summer of swimming. It's not the brushes, it's the liner.
Manually brush the waterline and the walls, treat the organic film, and try again. Many people replace perfectly good brushes for this problem.
4. The programmed cycle
Check the selected mode before looking further.
Several robots offer distinct programs: floor only, floor and walls, or floor, walls, and waterline. An accidental mode change, or a reset to factory settings after a power outage, sometimes puts the device back in floor mode.
This is a thirty-second check that sometimes prevents an unnecessary parts order.
5. Mechanical causes
The wheels or tracks are slipping. Turn them by hand. A sand-clogged axle, a tangled hair, or a loose belt reduces traction.
The float or ballast is out of adjustment. Some models have a buoyancy adjustment. A robot that is too heavy won't lift off the floor; if it's too light, it won't press against the wall.
The cable pivot is stuck. On a corded robot, a seized pivot causes the cable to twist and hold the device back. We discuss this in my robot turns in circles.
The diagnostic chart
| What you observe | Probable cause | What to do |
|---|---|---|
| It climbs a little then goes back down | Worn brushes | Replace the brushes |
| It won't leave the floor | Full filters, or floor mode | Clean, check the program |
| It climbed well in June, no longer in August | Greasy film on the walls | Brush and treat the liner |
| It slips on a specific wall | Locally dirty surface | Brush this area |
| It vibrates and doesn't move straight | Wheels or belt | Check traction |
| It pulls on its cable | Seized pivot, poorly unrolled cable | Unroll, check the pivot |
| It started after a liner change | Different grip | Adjust brushes or ballast according to the model |
The case of smooth liners and fiberglass pools
A very smooth wall, made of fiberglass or with a new liner with a slick finish, offers less grip than a slightly textured surface.
Some manufacturers offer specific brushes for these surfaces. If your robot climbed well in an older pool and refuses to climb in the new one, that's probably where to look rather than a breakdown.
Frequently asked questions
How often should I replace a robot's brushes?
It depends on the number of cycles and the surface. The right indicator is not the calendar, but the condition: rounded or flattened bristles signal the time.
My robot is new and doesn't climb. Is it defective?
First check the programmed mode and the cleanliness of the walls. In a pool whose liner hasn't been brushed in a while, even a new robot will slip.
Can I clean the brushes instead of replacing them?
Rinsing removes deposits and restores some bite, which is worth trying. If the bristles are mechanically worn, rinsing won't change anything.
My robot climbs but doesn't do the waterline.
The waterline requires a specific program that not all models offer. Check your device's capabilities before concluding it's defective.
Does brush wear affect floor cleaning?
Much less. That's why the symptom first appears on the walls: the floor continues to be cleaned well and nothing seems abnormal.
Our other guides on pool robots
- My pool robot no longer starts
- My robot turns in circles or leaves dirty areas
- How to maintain your pool robot
- When to replace a robot's wear parts
View our cleaning robots | Parts for automatic cleaners
Not sure which brushes to order? Send us the exact model of your robot. Write to us or call 450-818-8200.
