Line Mini-Split Heat Pump Series
41 codes
/
Fault

E4 Internal Fan Error / Sliding Door Error

LED

What it means

For wall-mounted PG motor models: the main internal control panel is not receiving the speed feedback signal from the PG motor. For wall-mounted and mobile DC motor models: the main internal control panel cannot receive rotational speed feedback through the DC motor's green plug connection. For floor standing sliding door models: the upper or lower photoelectric switch cannot sense the sliding door position normally. In all cases, primary causes are mechanical jam, a damaged speed feedback component, or a fault in the main internal control panel's receiving circuit.

Special attention The main internal control panel will not report a fan error while the fan is still rotating. Errors may go unreported even when obvious fan problems exist (such as low-speed rotation from damaged capacitors or uneven speed from abnormal feedback). For 3-core DC motor models: before startup, the fan blades will mechanically shake for 3–5 seconds during the blade position locking phase — this is normal and not a fault. For floor standing sliding door models: new machines may have the sliding plate secured with tape — remove before testing.

Inspection path

1 Fan or sliding plate for mechanical jam → 2 Speed feedback line or motor terminal connectors → 3 Speed feedback terminal connector on control panel → 4 Main internal control panel

Diagnostic procedure

  1. Check whether the fan can run for a period before the error appears. If so, mechanical jam can be excluded as the cause.
  2. Disconnect power and manually rotate the indoor fan blade to check for any resistance. Occasional fan errors may be related to bearing issues.
  3. For PG motor models: reconnect the drive wire and speed feedback wire to rule out connector loosening. For DC motor models: unplug and reseat the DC motor terminal connector.
  4. Check that the speed feedback plug-in terminal on the control panel is firmly seated. Gently tug if needed.
  5. For DC motor models: with the unit powering on in cooling mode, monitor voltage between the second (yellow) and fourth (black) wires of the DC motor terminal. Voltage should rise gradually and the motor should begin accelerating. If the motor does not rotate, the DC motor is damaged.
  6. Swap in a known-good motor (without mounting it to the fan assembly). If the error persists, replace the main internal control panel. If the error clears, replace the motor.
  7. For floor standing sliding door models: observe whether the sliding plate jams during startup or shutdown. If the door moves normally but the error persists, check the photoelectric switches. Verify the reversible synchronous motor is receiving 220V. Replace the faulty switch with a new sealed unit and confirm correct terminal color orientation — upper and lower photoelectric switches have different colored connectors and must not be swapped.

Tools

  • Multimeter
  • PG motor in working condition (PG motor models)
  • DC motor in working condition (DC motor models)
  • Photoelectric switch in working condition (floor standing only)

Frequent parts

  • Indoor fan (mechanical jam)
  • PG motor
  • DC motor
  • Main internal control panel
  • Photoelectric switch (floor standing only)
  • Reversible synchronous motor (floor standing only)
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

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

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

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 P5 Exhaust Protection F4 Exhaust 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 P7 Anti-Freezing Protection in Refrigeration Mode P6 Indoor High Temperature Protection E3 Internal Coil 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 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