What It Means
Actuation of low pressure switch (LPS).
Daikin Packaged Unit
Daikin Packaged Unit Error Code E4
Troubleshooting guide for the Daikin Packaged Unit system fault E4.
Possible Causes
- Abnormally drop in low pressure.
- Defective low pressure sensor.
- Defective outdoor unit PCB.
- Defective connector contact.
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.
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Full Diagnosis
Actuation of low pressure switch (LPS)
All Recorded Causes
Abnormally drop in low pressure Defective low pressure sensor Defective outdoor unit PCB Defective connector contact
Verify Before Replacing Parts
- Confirm the exact Daikin model family and packaged context before acting on a generic code description.
- Verify airflow first, then confirm operating pressures and temperature relationship before adjusting charge, since abnormally drop in low pressure.
- Look for restrictions, iced coils, or dirty heat-transfer surfaces that can mimic a charge problem, and separately confirm defective low pressure sensor.
- After the correction, run the system long enough to confirm the packaged fault does not return under normal load.
Still unsure about this fault?
ACLogics walks you through Daikin Packaged Unit diagnostics step-by-step — so you confirm the cause before swapping parts.
