Symptoms
- Unit runs for a few minutes then shuts off, then restarts soon after
- Room never quite feels comfortable
- Cycling happens even when the room isn't cold yet
- Compressor clicks on and off frequently
Likely causes
- CommonThermostat sensor near the coil is bent or miscalibratedIf the sensor touches the cold coil, the unit thinks the room is cold and shuts off early.
- CommonUnit oversized for the roomAn overpowered unit cools the air near the thermostat too fast and shuts off before the room evens out.
- PossibleDirty filter or blocked ventsRestricted airflow can trigger safety cutoffs that cycle the unit.
- PossibleLow refrigerant causing the coil to ice and the safety switch to tripIcing triggers repeated shutdowns as the unit protects itself.
What to do
- Remove the front cover and check that the small thermostat sensor (a thin wire near the coil) isn't touching the coil or bent out of place.
- Gently reposition the sensor a small distance from the coil, following the gap shown in the manual if available.
- Clean the filter and clear any blocked vents to restore normal airflow.
- Check whether the unit's BTU rating is much higher than recommended for the room size, which can cause short cycling even when working correctly.
- Run the unit for 30–60 minutes and time how long each cycle lasts; frequent cycling under 5–10 minutes suggests a sensor or airflow issue.
- If cycling continues after these checks, the issue may be low refrigerant or a failing control board.
Tools and parts
- Screwdriver
- Flashlight
When to call a pro
Call an appliance technician if adjusting the sensor doesn't stop the cycling, since that points to a refrigerant or electrical issue.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.