Robot Vacuum Troubleshooting

Most robot vacuum problems are one of eight things, and almost all of them are fixed by cleaning a component rather than by replacing the machine. A full bin, a clogged filter, a hair-wrapped brushroll and a dirty sensor between them account for the large majority of 'it stopped working properly' complaints.

This page recommends no products. That is deliberate - it is here to keep a machine you already own working, and the honest version of that page does not end with a buy button.

Almost always the filter. As it loads with fine dust, airflow drops steadily, and because it happens gradually you do not notice a day-to-day change - only that six weeks later the machine seems useless. Tap it out over a bin, and if it is a washable type, rinse and let it dry completely before refitting; a damp filter is worse than a dirty one.

Then the bin. A bin above about two-thirds full restricts airflow before the filter even comes into it. If the machine has no dock, this is a two- or three-day job with a pet in the house.

Then the inlet. Look at the underside. A single sock, a wad of hair or a bottle cap lodged in the inlet throat will not stop the machine and will stop it collecting anything.

The brushroll has a hair sleeve on it. Long hair wraps around the roller until it forms a solid tube, at which point the brush cannot turn freely and is smearing rather than agitating. Remove the brush - every machine here is designed for this without tools - and cut the sleeve off along the length with scissors, taking care not to cut the bristles.

Check the side brush too, and check it more often. It is thinner, unshrouded and slower-turning, which makes it the worst hair-wrap point on any robot vacuum, and it is the one most people never look at. The pet-hair page explains which brush designs reduce this.

It needs a 2.4 GHz network and your router is giving it 5 GHz. This is by far the commonest setup failure. Almost every machine here states a 2.4 GHz requirement, and modern mesh routers present both bands under one network name and decide for themselves which a device gets - including the phone doing the pairing.

The fix is to temporarily split the bands in your router settings, or create a 2.4 GHz-only guest network for the pairing and then switch back. It is a router problem rather than a vacuum problem, and no amount of resetting the machine will solve it.

Under a specific piece of furniture means the clearance is a fraction of an inch more than the machine's height - it drives in, the surface bows or the floor rises, and it wedges. The fix is a no-go zone if the machine maps, or a physical barrier if it does not.

On a rug edge or a threshold means the climb exceeds what the machine can manage. Published climbing figures here run up to 20 mm; a folded rug edge easily exceeds that. A rug gripper or a threshold strip fixes it permanently.

On dark flooring is a cliff-sensor false positive. The downward-facing infrared sensors read a very dark or matte surface as a drop and the machine refuses to cross. Cleaning the sensors sometimes helps; often the only fix is a no-go zone.

Something changed that the machine uses as a landmark. Moving a large item of furniture, or starting the machine from somewhere other than its dock, can be enough for it to decide it is in an unknown room and start a new map - taking your no-go zones with it.

Always start a run from the dock, and after moving furniture, run a full mapping pass deliberately rather than letting it discover the change mid-clean. Some apps let you lock a saved map, which is worth doing once you are happy with your zones.

A pad that went back on dirty. A mop pad has to be removed, rinsed and dried after every mopping run. If it goes back damp, it grows bacteria and the smell is that. If it goes back dirty, it redistributes last run's dirt.

Too much water on a sealed floor. Streaking is usually over-wetting rather than under-cleaning. Drop the flow setting a level.

Vacuuming and mopping in the same pass. Water laid onto a floor the machine is still lifting dry crumbs from makes paste. Schedule two separate jobs - a vacuum pass, then a mop pass.

Some decline is normal - these are lithium cells with a finite cycle count, and manufacturers in this price range do not publish one. But check the obvious first: a clogged filter or a hair-wrapped brush makes the motor work harder, and a machine fighting restriction flattens a battery noticeably faster. Clean everything, then reassess.

Also check whether the machine is running in a higher suction mode than it used to. Some apps raise power automatically on carpet, and a rug moved into the machine's path changes the whole run's consumption.

On a mapping machine, this is usually a closed door during the mapping run, so the room is simply not in the map. Re-map with every internal door open.

On a non-mapping machine, this is normal behavior and not a fault. Without a map the machine runs a pattern until the battery ends, and which rooms it reaches depends on where it started and what it bumped into. The navigation guide explains why, and it is the strongest practical argument for buying a machine with a map.