Line Mini-Split Heat Pump Series
41 codes
/
Fault

F0 External DC Fan Error (3-Core Terminal Motor)

LED

What it means

The frequency-converting outdoor unit uses a 3-lead-wire externally driven DC motor (used after 2012). It has no speed feedback circuit — the main control panel drives it directly and monitors current balance across the three lead wires. When the panel detects imbalanced current on those wires, it indicates this error.

Special attention Unlike 5-core internal DC motors, the 3-core external DC motor goes through a blade position locking phase before startup: the blades will mechanically shake for 3–5 seconds, then begin rotating slowly. This is normal behavior — do not diagnose it as a fault.

Inspection path

1 Mechanical jam of external fan blades → 2 Motor terminal connectors and wire order → 3 Main external control panel → 4 External DC motor

Diagnostic procedure

  1. Confirm there is no mechanical jam in the external fan blades.
  2. Verify the motor terminal is firmly connected and the wire order is correct. If the fan on a newly installed unit rotates in reverse, confirm the color order of the three lead wires or swap any two of the three motor wires to correct rotation direction.
  3. This 3-core DC motor scheme is reliable, so the drive section of the main external control panel is the more likely failure point. Replace the main external control panel with a matched unit. If the fan returns to normal, the original control panel is faulty. If the error persists, replace the external DC motor.

Tools

  • Main external control panel in normal working condition

Frequent parts

  • Mechanical jam of external fan
  • Main external control panel
  • External DC motor
Safety Disconnect power at the breaker before opening any access panel. DC bus capacitors retain charge for up to 5 minutes after disconnect - verify with a meter before touching live components.
Sensor Reference 6

Internal temperature

15 kΩ @ 25°C
Too-high resistance Detected temperature reads lower than actual. May cause shutdown errors in heating mode or startup failures in cooling mode.
Too-low resistance Detected temperature reads higher than actual. May cause startup errors in heating mode or shutdown failures in cooling mode.
Triggers E1 Internal Temperature Sensor Error

External coil

20 kΩ @ 25°C
Too-high resistance Detected temperature reads lower than actual. May cause frequent entry into defrost mode, illusory defrost cycles, or protection errors during cooling.
Too-low resistance Detected temperature reads higher than actual. May cause defrost failures during heating or protection activation during cooling.
Triggers P4 Refrigeration Overload Protection E2 External Coil Sensor Error

Internal coil

20 kΩ @ 25°C
Too-high resistance Detected temperature reads lower than actual. May cause high-pressure cold-blast protection during heating or frequent anti-freezing protection during cooling.
Too-low resistance Detected temperature reads higher than actual. May cause frequent overheat protection during heating or overload protection during cooling.
Triggers P6 Indoor High Temperature Protection P7 Anti-Freezing Protection in Refrigeration Mode E3 Internal Coil Sensor Error

Exhaust

50 kΩ @ 25°C
Too-high resistance Detected exhaust temperature reads lower than actual. The system may fail to activate protection when exhaust temperature is genuinely dangerous.
Too-low resistance Detected exhaust temperature reads higher than actual. The unit enters high exhaust temperature protection frequently, compressor frequency threshold rises, leading to unwanted shutdowns. Example: installing a 20KΩ coil sensor in place of the 50KΩ exhaust sensor produces this behavior.
Triggers F4 Exhaust Sensor Error P5 Exhaust Protection

External temperature

15 kΩ @ 25°C
Too-high resistance Detected outdoor temperature reads lower than actual, causing incorrect temperature-based control decisions.
Too-low resistance Detected outdoor temperature reads higher than actual, causing incorrect temperature-based control decisions.
Triggers F6 External Temperature Sensor Error

Recirculated

20 kΩ @ 25°C
Too-high resistance Incorrect back temperature value affects electronic expansion valve adjustment and four-way valve position confirmation during heating.
Too-low resistance Incorrect back temperature value affects electronic expansion valve adjustment and four-way valve position confirmation during heating.
Triggers FA Recirculated Sensor Error