Archives: Troubleshooting

A robot pool cleaner that is not picking up debris is usually losing suction or grip: a full or clogged filter basket, debris jammed in the impeller, worn brushes that no longer lift dirt off surfaces, or a filter too coarse for the debris you have, so clean the filter and impeller and match the filter grade to the mess first.

The usual causes

• Full or clogged filter. Once the basket or cartridge fills, water and debris can no longer flow through, so the cleaner stops collecting even while it keeps moving.
• Jammed impeller. Leaves, hair, or pebbles caught around the impeller cut suction sharply.
• Worn or flattened brushes. Brushes that have worn down cannot agitate dirt loose from the floor and walls, so it is never lifted into the intake.
• Wrong filter grade. A coarse filter passes fine silt and sand straight back into the water, while a fine one can blind quickly on large debris.
• Poor floor contact. Worn tracks or tires that slip stop the unit from pressing debris toward the intake.

Steps to try

1. Empty and rinse the filter. Remove the basket or cartridge and clear it fully after every use. Rinse cartridges with a hose, and replace any that stay gray or stiff after cleaning.
2. Clear the impeller. With the unit unplugged, open the intake area per your model and remove anything wound around or lodged in the impeller. Turn it by hand to confirm it spins freely.
3. Inspect the brushes. Compare brush height to a wear line if your model has one. Flattened or short brushes should be replaced so they can lift dirt again.
4. Match the filter to the debris. Fit a fine filter for silt, sand, and pollen, and a coarser one for leaves and larger material. Some pools need a mid-season switch as the debris type changes.
5. Check tracks or tires for grip. Look for worn, cracked, or slick drive surfaces. Poor grip means the cleaner drifts over debris rather than working it toward the intake.
6. Confirm coverage. Watch a full cycle. If whole zones are skipped, a path or steering issue may be leaving debris untouched rather than a suction problem.

Water and setup factors

• Debris beyond the design. Very fine dust or heavy storm debris can exceed what the filter is built to capture in one pass.
• Running too seldom. Long gaps let debris settle and bond to surfaces, which a single cycle cannot fully lift.
• Cycle too short. A cleaner pulled out early may not reach the whole pool, leaving debris that looks like a pickup failure.

When it is the cleaner, not the pool

If the filter is clean, the impeller is clear, the brushes and tracks are in good shape, and debris still passes untouched, the fault has likely moved inside the unit. Weak or no suction with a clean flow path points to a failing pump motor, a cracked impeller housing leaking suction, or a control fault that never brings the pump to full speed. A drive motor that no longer holds the cleaner against the floor will also leave debris behind. These are larger repairs to weigh against the age of the cleaner. For how these units are expected to perform and where their limits sit, see our coverage of robot pool cleaner autonomy, and follow reliability signals and recalls on the Tracker.

A robot pool cleaner cable that keeps tangling is usually caused by the cord holding a coiled memory from storage, a swivel that has seized and no longer lets the cable rotate, too much cable length let out for the pool, or a cleaner that keeps turning in one direction, so straighten the cable set and free the swivel first.

The usual causes

• Coiled cable memory. A cord stored wound tightly keeps that shape in the water and works itself into loops as the cleaner moves.
• Seized or worn swivel. Many corded cleaners use an inline swivel joint that lets the cable untwist. When it stiffens or fails, twists accumulate into knots.
• Too much cable in the pool. Excess length beyond what the pool needs gives the cord room to fold back on itself.
• One-directional cleaning path. A cleaner that repeatedly circles the same way winds the cable up over a cycle.
• Return jet interference. Strong water return can push the cable across the cleaner’s path and bunch it.

Steps to try

1. Relax the cable in the sun. Lay the full cord out straight on a warm, flat surface for a while. Mild warmth lets a coiled set relax so the cable lies flatter in the water.
2. Check the swivel turns freely. Find the swivel joint and twist the two sides by hand. It should rotate with little resistance. If it is stiff or gritty, clean it, and if it will not free up, plan to replace it.
3. Let out only the cable you need. Feed out roughly enough length to reach the far point of the pool plus a small margin, and no more. Keep the rest coiled loosely at the edge.
4. Reposition the power supply. Set the unit so the cable enters the water from a corner or a point that gives the cleaner an even reach across the whole pool.
5. Lower return jet flow if possible. Angle return fittings downward or reduce flow during a cleaning cycle so the current does not shove the cable around.
6. Untwist after each run. When you pull the cleaner out, walk the cable straight and let the swivel shed any accumulated twist before storing.

Storage that prevents tangles

• Loose, wide loops. Coil the cable in large loops rather than tight winds, and avoid sharp bends that set a permanent kink.
• Off the ground. Hang the cord or lay it flat instead of leaving it crushed under the unit, which forces a coiled shape.
• Alternate loop direction. Reversing the coil direction between uses keeps a consistent twist from building into the cord.

When it is the cleaner, not the pool

If the cable lies flat, the length is right, and the swivel turns freely yet tangles still form every cycle, the cause may be inside the unit. A cleaner that always veers or circles one way can point to uneven drive tracks, a worn drive motor pulling harder on one side, or a steering or control fault that stops it from varying its path. A swivel that has failed internally will also keep twisting no matter how you store the cord. Replacing a swivel is minor, but a drive or control issue can be a larger repair to weigh against the age of the cleaner. For how these units are meant to navigate and where their limits sit, see our coverage of robot pool cleaner autonomy, and track reliability patterns and recalls on the Tracker.

A robot mower reporting no loop signal or a lost satellite fix has lost the reference it uses to know where it is: on boundary-wire models that means a broken loop, a dead base station, or a loose connection, and on wire-free RTK models it means the antenna or mower cannot see enough satellites.

Wire-based (loop signal) causes

• Broken or cut boundary wire. A single break anywhere in the loop stops the signal around the entire perimeter. Cuts come from digging, edging tools, frost heave, and rodents.
• No power to the base station. A tripped outlet or unplugged supply leaves the loop with nothing to energize it, so the mower reads no signal even with the wire intact.
• Loose wire terminals. The loop ends can back out of the base station connectors, especially after weather or vibration.
• Interference. Nearby buried cables, metal, or another mower’s loop can disturb the signal near certain sections.

Wire-free (satellite) causes

• Blocked sky view. The reference antenna or the mower under dense tree canopy, next to tall buildings, or beside a solid fence cannot lock onto enough satellites.
• Reference station moved or unpowered. The fixed antenna needs a stable, powered, open-sky position. If it was moved or lost power, the mower loses its correction.
• Connection dropout. RTK systems rely on a data link between the reference and the mower. A weak link in far corners breaks the precise fix.

Fixes to try in order

1. Confirm the base station has power. Check the outlet and the supply indicator. Restore power and watch whether the signal light returns to a steady state.
2. Reseat the loop connections. On wire systems, open the base station and make sure both loop ends are firmly seated in the correct terminals.
3. Find and repair a wire break. Walk the perimeter for disturbed ground and visible damage. Many models signal a break with a specific indicator pattern, so check the base station lights against the manual. Splice cleanly with a waterproof connector.
4. Clear the sky view. On RTK systems, confirm the reference antenna sits in the open, is powered, and has not shifted. Trim overhanging branches and move the antenna away from walls and metal.
5. Re-check corners and far zones. If the fix drops only in certain areas, the problem is local: a wire section near interference, or a spot where satellite coverage or the data link is weak.
6. Restart the system. Power the base and the mower off and on so both re-establish the signal or satellite fix from a clean state.

When it is the mower, not the lawn

If the base is powered, the loop tests continuous, or the antenna has clear sky and the mower still cannot hold a signal, the fault may be internal. A failing signal receiver, a damaged antenna on the mower, a worn wheel motor that strands it outside coverage, or a firmware regression that changed how the mower reacquires its fix after an update can each produce a persistent no-signal state. Note whether the error appeared right after a firmware update, since that points to software rather than hardware. Follow model-specific reports and update notes on the Tracker, and see our overview of robot mower autonomy.

A robot mower that leaves uncut patches is usually cutting with worn blades, running a coverage pattern that misses corners and narrow passages, steering around obstacles or wet spots, or simply not getting enough run time to reach the whole lawn.

The usual causes

• Worn or damaged blades. Dull, chipped, or bent blades tear rather than cut and drag through thicker growth, leaving standing grass in denser areas.
• Coverage pattern gaps. Corners, narrow strips between beds, and areas past a tight passage are common misses because the mower cannot maneuver fully into them.
• Obstacles and no-go zones. Furniture, toys, low branches, and mapped exclusion zones make the mower steer away, leaving a ring of uncut grass around each object.
• Slopes and slippery ground. On inclines or wet grass the wheels can slip, so the mower covers less ground than its pattern intends.
• Run time too short for the area. If the schedule or battery runtime does not match the lawn size, the mower charges before it finishes, and the same far corners get skipped each cycle.
• Boundary or position drift. A boundary wire placed too far inside the edge, or an RTK mower with a weak fix near tree cover, can keep the mower off the true perimeter.

Fixes to try in order

1. Inspect and replace the blades. Power down the mower, turn it over, and check each blade for dullness, chips, and free movement. Replace a worn set rather than sharpening if the design uses small pivoting blades.
2. Raise the cutting height, then lower gradually. If grass is tall or dense, set a higher deck first and step it down over several sessions so the mower is not forced to muscle through heavy growth in one pass.
3. Increase run time or frequency. Lengthen the schedule or add sessions so the mower has time to reach every zone, especially far corners and areas behind passages.
4. Clear and re-check obstacles. Remove movable items before each run and trim low branches. Review any mapped no-go zones and confirm they are not larger than intended.
5. Adjust the boundary or mapping. For wire systems, reposition the perimeter wire so the mower reaches the true edge. For RTK systems, confirm a strong satellite fix and remap corners that sit under tree cover or beside buildings.
6. Check the wheels and tires. Clean caked grass from the drive wheels so they grip and track the pattern accurately on slopes and damp ground.

When it is the mower, not the lawn

If the blades are sharp, the schedule is generous, and the yard is clear but patches still appear in the same places, suspect an internal fault. A worn wheel motor that slips under load, a failing tilt or position sensor that cuts a pass short, a cutting motor that bogs down in normal grass, or a firmware regression that changed the coverage pattern after an update can each leave repeatable missed spots. Note whether the skips started right after a firmware update, since that points to software. Track model-specific reports and update notes on the Tracker, and see our overview of robot mower autonomy.

A robot mower that will not charge or return to its base is usually blocked by dirty or corroded charging contacts, no power reaching the dock, a docking station placed where the mower cannot line up with it, or a boundary and guide signal the mower can no longer follow home.

The usual causes

• Dirty or corroded charging contacts. The metal strips on the mower and the dock build up oxidation, grass film, and moisture residue. Poor contact means the mower parks but never draws a charge.
• No power at the dock. A tripped outlet, a cut or chewed low-voltage cable, or an unplugged power supply leaves the base dead even though the mower docks correctly.
• Docking station placement. A dock on a slope, on uneven ground, or too close to a wall or corner can stop the mower from aligning its contacts.
• Lost return path. Boundary-wire mowers follow the perimeter wire or a guide wire back to the dock; wire-free RTK mowers navigate by satellite position. A break, a signal drop, or a poor return location blocks the trip home.
• Depleted or aging battery. A battery near the end of its service life may report a charge it cannot hold, so the mower leaves the dock and stalls quickly.

Fixes to try in order

1. Clean both sets of contacts. Power down the mower, then wipe the charging strips on the mower and the dock with a dry cloth or fine abrasive pad until the metal is bright. Remove any grass or debris packed around them.
2. Confirm the dock has power. Check the outlet with another device, inspect the full length of the low-voltage cable for cuts or rodent damage, and verify the power supply indicator light if the model has one.
3. Reseat the mower by hand. Place it on the dock manually and watch whether the charge indicator responds. If it charges when placed by hand but not on its own, the problem is the return path or alignment, not the charger.
4. Check the docking approach. Make sure the dock sits on firm, level ground with clear space in front of it. Clear grass clippings, sticks, and standing water from the approach lane.
5. Test the boundary and guide signal. For wire-based systems, confirm the base station signal light is steady and walk the perimeter for visible wire breaks. For RTK systems, confirm the reference antenna has a clear sky view and a stable satellite fix before the return trip.

When it is the mower, not the lawn

If the contacts are clean, the dock has power, and the mower still will not charge or find its way home, the fault may be internal. A battery that drops charge within minutes, a charging circuit that never engages a clean hand-placed dock, a failing position sensor that misreads the approach, or a firmware regression that changed docking behavior after an update can each produce these symptoms. Note whether the trouble began right after a firmware update, since that points to software rather than hardware. Watch for known model issues and update notes on the Tracker, and see our overview of robot mower autonomy.

A robot vacuum that shows as offline in the app is usually still running fine but has lost its link to your Wi-Fi or the manufacturer’s servers: confirm the robot has power and signal, restart your router and the app, and if it still will not reconnect, remove the robot from the app and add it again on your 2.4 GHz network.

Why the app loses the robot

• A weak Wi-Fi signal at the dock. If the dock sits far from the router or behind walls, the robot drops off when the signal fades.
• A router or password change. A new router, a renamed network, or a changed Wi-Fi password breaks the saved connection until the robot is set up again.
• A 5 GHz only network. Nearly all robot vacuums use the 2.4 GHz band only. If your phone or router pushed the robot onto 5 GHz, it cannot stay connected.
• The robot is off the dock or powered down. A robot with a drained battery, a flipped power switch, or a resting spot far from the dock will show as offline.
• A server or app outage. The status also depends on the manufacturer’s servers. When those are down, the robot can work while the app still reads offline.

Fix it in order

1. Confirm the robot has power. Return it to the dock, check that it is charging, and make sure any physical power switch is on.
2. Restart the app and your phone. Fully close the app and reopen it, or restart the phone, to clear a stale connection.
3. Restart your router. Power the router off for about thirty seconds and back on, then give it a minute to come up before checking the app.
4. Check for an outage. If nothing on your network changed, wait and try later, since a server outage clears on its own.
5. Confirm you are on 2.4 GHz. Put your phone on the 2.4 GHz network before any re-setup so the robot is not handed a band it cannot use.
6. Remove and re-add the robot. Delete the robot from the app and run setup again. Check the manual for the exact button or hold needed to put your model into pairing mode.
7. Move the dock closer if signal is weak. If the robot keeps dropping, relocate the dock nearer the router or add coverage to that area.

When it is the robot, not the network

If other devices hold Wi-Fi in the same spot and the robot alone keeps dropping, the fault may sit with the robot. Signs of an internal cause include a robot that will not enter pairing mode, a connection that fails only after a firmware update, or repeated disconnects that began without any change to your network. A firmware regression usually shows up across many units of the same model at the same time, which separates it from a local Wi-Fi problem. You can check whether others are reporting the same connection issue on the Tracker, and for how remote control and app dependence fit into a robot’s independence, see our assessment of robot vacuum autonomy.

A robot vacuum that suddenly has weak suction or stops picking up is almost always clogged or full: empty the bin, clear the brush roll and air path of hair and debris, and clean or replace the filter. Suction usually returns once the airflow is unblocked.

What weak suction usually means

• A full or poorly seated bin. A dustbin that is full, or not clicked fully into place, chokes airflow and can stop pickup entirely.
• A clogged filter. Fine dust packs into the filter over time. A gray, matted filter is the single most common cause of gradual suction loss.
• Hair wrapped on the brush roll. Hair and fiber wind tightly around the roll and its end caps, stopping it from turning and lifting debris.
• A blocked air path. Debris can lodge in the intake nozzle or the channel between the brush and the bin, sealing off suction.
• Worn brushes or bin seals. Flattened bristles and cracked or missing rubber seals let air leak instead of pulling it through the floor.
• A low battery or a quiet mode. Many robots reduce suction as the battery drains or when set to an eco or quiet profile.

Fix it in order

1. Empty the bin and reseat it. Empty it fully, then push it back until it clicks. Confirm no lid or flap is stuck open.
2. Clean or replace the filter. Tap out loose dust and brush the surface. Rinse it only if the manual says the filter is washable, and let it dry fully before refitting. Replace filters that stay gray.
3. Clear the brush roll. Remove the roll, cut away wound hair with scissors, and clean the end caps and bearings where hair collects.
4. Check the nozzle and air channel. Look into the intake and the passage to the bin, and remove any clump you can reach.
5. Inspect side brushes and wheels. Free the side brushes and drive wheels of tangled hair so the robot can hold the floor and feed debris to the intake.
6. Raise the suction level and charge fully. Set a higher suction mode in the app and test on a full charge to rule out power-saving behavior.

When it is the robot, not the debris

If suction stays weak after the bin, filter, brush, and air path are all clean, the cause may be inside the machine. Signs of an internal fault include a fan motor that sounds strained or unusually quiet, a bin that will not hold a seal even with a new gasket, or a drop in pickup that started right after a firmware update. When an update is the trigger, many owners of the same model tend to report it together, which helps separate a software regression from ordinary wear. You can follow reported firmware issues on the Tracker, and to understand where suction sits within a robot’s wider capabilities, see our overview of robot vacuum autonomy.

Most robot vacuums streak when mopping because the pad is already saturated with dirty water, the tank is releasing too much liquid, or dried cleaner residue on the floor is being pushed around: rinse or replace the pad, use plain water or a robot-safe solution, and vacuum the floor before the mop pass.

Common reasons a mop pad streaks

• A dirty or saturated pad. A pad already holding dirt and gray water spreads a thin film rather than lifting it. Streaks that appear only after the first few minutes usually point here.
• Too much water. When the tank releases more liquid than the pad can spread evenly, the floor dries in uneven bands. Many robots let you lower the flow rate in the app.
• Cleaner residue. Soap that is too strong, or a floor cleaner left from an earlier manual mopping, leaves a sticky layer the pad smears into streaks.
• Loose debris on the floor. Grit and hair caught under the pad drag across the surface. A mop pass is not a substitute for a vacuum pass.
• An uneven or worn pad. A pad that is folded, clipped in crooked, or frayed makes contact in patches rather than across its full width.

Fix it in order

1. Start with a clean pad. Rinse the pad thoroughly or fit a fresh one. Wring reusable pads until they are damp, not dripping.
2. Lower the water flow. If your robot offers water level settings, set a lower level and run a short test on a small area.
3. Switch to plain water or a robot-safe solution. Avoid ordinary floor soap, oil-based cleaners, and vinegar unless the manual approves them. Most streaking from residue clears once the cleaner is removed.
4. Vacuum first, then mop. Run a vacuum-only pass, or use a mode that vacuums before mopping, so the pad is not dragging grit.
5. Reseat the pad. Check that the pad sits flat and square, with no folded corners, and that the mounting plate is free of buildup.
6. Empty and refill the tank. Old water can carry residue. Rinse the tank and refill with clean water.

When it is the robot, not the floor

Some streaking is mechanical rather than a matter of technique. Signs the fault is internal include a water pump that no longer meters flow evenly, a vibrating or rotating mop plate that has stopped moving, or streaks that began right after a firmware update changed how the robot handles water. Uneven wetting across the width of every pass, regardless of pad or setting, points to hardware. When a software update is the trigger, the behavior often affects many units of the same model at once. You can watch for reported firmware regressions on the Tracker, and for a broader view of how mopping fits into a robot’s overall capability, see our assessment of robot vacuum autonomy.

A robot pool cleaner that will not move or climb walls is usually held back by something mechanical: debris jamming the impeller or drive tracks, a clogged filter that kills suction and grip, a tangled cable, or trapped air making it too buoyant. Clearing the debris path fixes most cases.

Why climbing fails first

Wall climbing needs both drive traction and suction against the surface. Anything that reduces either, a full filter or a jammed track, shows up as a cleaner that still works the floor but slides back down the walls, before it stops moving altogether.

The usual causes

• Clogged filter or basket. A full filter cuts the flow the cleaner needs to hold a wall and to drive. This is the most common cause by far.
• Debris in the impeller or tracks. Leaves, acorns, or small stones jam the impeller or wedge in the tracks and brushes and stall the drive.
• Worn tracks or brushes. Smooth, worn tracks and flattened brushes lose grip on the wall.
• Tangled or short cable. A twisted cable pulls the unit off the wall; a cable too short for the pool stops it reaching the far side.
• Trapped air or low water. Air left inside makes the cleaner too buoyant to hold the floor; a low water level starves the intake.

Fix it in order

1. Empty and rinse the filter. Clean the basket or cartridge after most cycles. Reduced climbing is nearly always the first sign it is full.
2. Clear the impeller and tracks. Power off and unplug, then remove debris from the impeller housing, tracks, and brushes.
3. Purge trapped air. Lower the cleaner in slowly and tilt it so air escapes before it sinks and starts.
4. Untangle and check the cable. Straighten the cable and let it relax in the sun; confirm its length suits the pool.
5. Check water level and wear. Keep the water at the midpoint of the skimmer, and replace worn tracks or brushes if grip is gone.

When it is the cleaner, not the pool

If the filter is clean, nothing is jammed, and it still will not drive or climb, the cause is more likely a worn drive motor, a failed pump, or a control fault. Corded and cordless pool robots fail in different ways, and reliability by model is recorded on the robot’s record and in the Tracker. For what a pool robot should reach on its own, see robot pool cleaner autonomy.

A robot mower that keeps stopping is usually reacting to something it is built to stop for: wet or tall grass, a slope near its climb limit, a lifted or tilted deck, a blocked wheel, or a lost boundary signal. The message on the mower or in the app almost always names which one.

Read the reason first

Unlike a stuck vacuum, a mower that stops normally tells you why, on its screen or in the app. Start there; the fixes below map to the common messages.

The usual causes

• Wet or very tall grass. Wet clippings clog the deck and bog the blade; grass above the cutting range stalls the motor. Mow when dry, and drop the height for a first pass on long grass.
• Slope near the limit. Most consumer mowers handle roughly 20 to 30 percent grade. Near that limit, wet or loose turf makes the wheels slip and the mower stops.
• Lift or tilt. Safety sensors stop the blade the instant the mower is lifted or tips past a set angle. Uneven ground, molehills, or a wheel dropping into a hole can trip this.
• Blocked wheels or blade disc. Packed grass and mud around a wheel or the blade disc make the mower think it is stuck.
• Lost boundary or satellite signal. Wire mowers stop when the perimeter loop breaks; wire-free RTK mowers stop when they lose the satellite fix under trees or beside buildings.

Fix it in order

1. Clear and clean. Power off, clear packed grass from the wheels, deck, and blade disc, and check the blades turn freely.
2. Mow dry, in stages on long grass. Reschedule around watering and rain; on overgrown lawns cut from a higher setting down over several passes.
3. Smooth the trouble spots. Fill holes and level molehills where the tilt sensor trips, and set a no-go zone around a slope it cannot hold.
4. Check the boundary or signal. For wire mowers, look for a break in the loop (usually shown as a signal error). For RTK mowers, note whether stops cluster under tree canopy or beside the house, where the sky view is poor.

When it is the mower, not the lawn

If it stops on flat, dry, open lawn with no message that fits, the cause is more likely a worn wheel motor, a failing tilt or lift sensor, or a fault from a firmware update. Reliability patterns and post-update changes per model are recorded on the robot’s record and in the Tracker. For what a mower should manage on its own, see robot mower autonomy.