Skip to main contentStart diagnosing L4 on your Daikin heat pump
What this code means
Radiation fin temperature rise – radiation fin temperature is above threshold with compressor on.
First step from the service manual
Turn off the power, then turn on the power to restart the system. Check if PCB has been replaced and silicone grease is properly applied.
Next steps: diagnose the root cause
1
Verify the error code is active
Power cycle the unit and see if the code returns. If it does, the fault is persistent and requires diagnosis.
2
Get the full diagnostic procedure
Get step-by-step guidance, test values, and wiring diagrams from the OEM service manual.
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What’s available for Daikin heat pump models
Access Daikin heat pump service manuals, wiring schematics, exploded parts views, and error code references on MyPros+.