Cause one: the wrong litter
Crystals in a clumping machine, tofu in a mineral-only one. Read the manual’s list, not the marketing.
Cause two: too much litter
Over-filling stops the drum turning cleanly and drags clumps against the wall. Manufacturers publish a level line; it is there for this reason.
Cause three: dust on the sensors
Wipe the infrared windows every time you change litter. Ten seconds.
Cause four: the seal
A perished drawer seal leaks, and a leaking drawer eventually gums the mechanism. It is a cheap part and it is the one people replace last.
This does not replace your machine’s manual. Sensor thresholds, cycle delays and temperature limits differ between models, and the manufacturer’s instructions for yours take precedence over anything written here.
The questions owners ask
Which litter jams a box?
Any litter the machine was not built for: crystals in a clumping machine, plant litters in a mineral-only one, and soft slow-setting clay in a rake box. The manual’s list is the specification, not a suggestion.
The sensors trigger for no reason. Why?
Dust, usually. Fine litter dust settles on infrared sensors inside an enclosed drum, and a sensor that mis-reads stops a cycle or starts one at the wrong moment. Wipe them when you change litter.
Last reviewed 2026-08-17