How Detection Works (by Model)
Litter-Robot 3
Uses a weight-based cat sensor (like a scale). The Reset button "zeros" the scale so it can detect your cat accurately.
Litter-Robot 4
Uses OmniSense sensors (curtain sensors in the bezel) plus a weight scale. Debris in the bezel/curtain sensor openings can cause false detects.
Common Detection Issues
1. Not Detecting Cat Entry (Doesn't Cycle After Use)
Most common causes:
- LR3: Cat is under 5 lb (2.2 kg) — auto mode not recommended for kittens
- Unit needs a Reset after changes (adding/removing litter, emptying drawer, moving/cleaning)
- Placement issues: not level, too close to a wall, on a mat/carpet affecting sensitivity
- Too much litter/weight can interfere with detection
How to fix:
- Ensure the unit is on a firm, level surface and not touching a wall/furniture
- Make sure litter is at or below the fill line and not excessively heavy
- With the unit in Home/Ready (solid blue light), press Reset once
- Don't lean on the unit while pressing Reset
- If your cat is under 5 lb on LR3, use manual cycle until they're heavier
2. False Detects ("Ghost Cycles" When Empty)
The unit thinks a cat is present when nothing is there, triggering unnecessary cycles.
How to fix:
- Remove anything touching the unit (bags, cords, litter mats pushing against it)
- Pull it 2–3 inches away from walls and confirm it's level/stable
- Press Reset once while in Home/Ready position
3. Red Light / "Cat Sensor Fault" (Won't Clear)
This usually means the sensor thinks it's continuously activated — often due to excess weight, too much litter, or a cat lingering inside.
How to fix:
- Verify no cat is inside the globe
- Check for excess litter or extra weight on the unit
- Press Reset once while in Home/Ready
Cleaning (Model-Specific)
Litter-Robot 4: Bezel & Curtain Sensor Cleaning
- Wipe the bezel area with a dry, clean cloth
- Vacuum the inside perimeter of the bezel with a brush attachment, especially across the holes at the top
- If needed, gently clean sensor surfaces with a dry cotton swab
Tip: Don't spray liquids into sensor openings. Use dry methods only.
Litter-Robot 3: Cat Sensor Best Practices
- Press Reset after anything that changes weight/placement (emptying drawer, adding litter, moving/cleaning)
- Keep it level, stable, and not touching walls or furniture
- Avoid placing on thick carpet or litter mats that can affect weight sensing
Adjusting Cycle Delay (Clumping Time)
The cycle delay is how long the unit waits after your cat exits before starting a clean cycle. This gives litter time to clump.
| Model | Options | Default |
|---|---|---|
| Litter-Robot 3 | 3 / 7 / 15 minutes | 7 min |
| Litter-Robot 4 | 3 / 7 / 15 / 25 / 30 minutes | 7 min |
When to adjust:
- Increase delay if clumps smear or stick, or if you use slow-clumping litter
- Decrease delay to reduce odor, or if you have a dog that raids the litter box
Monitor your sensors remotely
RobotSitter.io watches your Litter-Robot's sensor status and alerts you immediately when issues occur — even when you're away from home.