What It Means
Malfunction of outdoor air thermistor.
Daikin Split & Multi-Split
Daikin Split & Multi-Split Error Code H9
Troubleshooting guide for the Daikin Split & Multi-Split system fault H9.
Possible Causes
- Defective connection of thermistor.
- Defective outdoor unit PCB.
- Defective outdoor air thermistor.
Not sure which one it is — or if it's none of these? Try ACLogics today.
Disclaimer: This information is for general reference. Error codes can vary by model and production year. Always refer to your machine's specific manual and the information printed on the unit itself.
New to this code? Click to see why this happens
Full Diagnosis
Malfunction of outdoor air thermistor
All Recorded Causes
Defective connection of thermistor Defective outdoor unit PCB Defective outdoor air thermistor
Verify Before Replacing Parts
- Confirm the exact Daikin model family and split/ multi split context before acting on a generic code description.
- Verify the sensor or thermistor reading against the expected range for the current operating condition, keeping in mind that defective connection of thermistor.
- Check the sensor harness and board connection before condemning the sensor itself; on Daikin units this is also where you'd confirm defective outdoor unit PCB.
- After the correction, run the system long enough to confirm the split/ multi split fault does not return under normal load.
Still unsure about this fault?
ACLogics walks you through Daikin Split & Multi-Split diagnostics step-by-step — so you confirm the cause before swapping parts.
