Haier AC error codes – Split AC
31 codes from the Haier service manual, with what each one means and the usual causes. Checks are standard practice.
You can safely switch the unit off at the switch, wait 5 minutes and switch on again. Don't open the unit, touch wiring or handle gas: these checks need a trained technician.
E1
Indoor room sensor failure
What our technician checks
- Room (return air) sensor: unplug and measure - most split ACs use 10 kΩ at 25°C (about 12.6 kΩ at 20°C, 8 kΩ at 30°C). Open or short = faulty. Check connector on the indoor PCB.
E2
Indoor pipe sensor failure
What our technician checks
- Indoor coil (pipe) sensor: unplug and measure (commonly 10 kΩ or 5 kΩ at 25°C depending on brand). Check it is clipped into the coil sensor pocket.
E4
Indoor EEPROM failure
What our technician checks
- Power off 3 min and restart.
E5
Indoor anti-freeze protection
What our technician checks
- Indoor filter / coil dirty, blower slow, low gas, very low set temperature with low indoor load.
E7
Indoor-outdoor communication fault
What our technician checks
- Interconnect cable: correct terminal order (L, N, signal, earth), no loose screw or joint, cable not run with other power cables. Is the outdoor unit powered (LED on outdoor PCB)? Signal line voltage fluctuates when healthy. Check outdoor fuse and reactor.
E9
Indoor overload in heating
What our technician checks
- Condenser dirty or air recirculating, outdoor fan slow, overcharge, air / nitrogen in system, valves closed (heating: indoor filter / fan).
E14
Indoor fan motor fault
What our technician checks
- Indoor blower turns freely by hand? Blower wheel clean, not rubbing? Fan motor connector, motor supply (AC: capacitor
- DC: about 310 V DC + 15 V and feedback signal).
F1
IPM protection
What our technician checks
- Power off, wait for capacitors to discharge. Compressor U-V, V-W, W-U equal (about 0.5-3 Ω) and >10 MΩ to earth. Diode test the IPM P/N to U/V/W. Check DC bus (about 310 V DC on 230 V supply), heat-sink paste and screws, condenser cleanliness, supply voltage, overcharge.
F2
Compressor instant over-current
What our technician checks
- Supply voltage under load, condenser dirty or outdoor fan slow, overcharge, air in system, compressor current against rated.
F3
Communication between power module and main PCB
What our technician checks
- Interconnect cable: correct terminal order (L, N, signal, earth), no loose screw or joint, cable not run with other power cables. Is the outdoor unit powered (LED on outdoor PCB)? Signal line voltage fluctuates when healthy. Check outdoor fuse and reactor.
F4
Discharge temperature protection
What our technician checks
- Low refrigerant charge (most common), blocked expansion valve / capillary, EEV not opening, discharge sensor reading wrong.
F6
Outdoor ambient sensor failure
What our technician checks
- Outdoor sensor (ambient / coil / suction): unplug and measure against the brand chart (outdoor ones are usually 10 kΩ, discharge sensors 50-200 kΩ at 25°C).
F7
Suction temperature sensor failure
What our technician checks
- Outdoor sensor (ambient / coil / suction): unplug and measure against the brand chart (outdoor ones are usually 10 kΩ, discharge sensors 50-200 kΩ at 25°C).
F8
Outdoor DC fan motor fault
What our technician checks
- Outdoor fan turns freely (bearing)? Leaves / debris? DC fan: motor supply from the outdoor PCB and feedback wire.
F9
Module reset (supply dip)
What our technician checks
- Measure mains under load (single phase normally 200-250 V). Loose neutral, undersized cable, stabiliser.
F11
Compressor loss of synchronism
What our technician checks
- Compressor windings equal and not earthed? U/V/W lead order and connection. Refrigerant pressures equalised before start? Board output to compressor.
F12
Outdoor EEPROM failure
What our technician checks
- Power off 3 min and restart.
F13
Lack of refrigerant
What our technician checks
- Suction pressure low? Leak test (flare joints, valves, coils) with soap / nitrogen. Valves fully open?
F14
4-way valve reversing failure
What our technician checks
- 4-way valve coil voltage and resistance
- valve sticking (heating models).
F19
Supply over / under voltage
What our technician checks
- Measure mains under load (single phase normally 200-250 V). Loose neutral, undersized cable, stabiliser.
F20
High pressure protection
What our technician checks
- Condenser dirty or air recirculating, outdoor fan slow, overcharge, air / nitrogen in system, valves closed (heating: indoor filter / fan).
F21
Outdoor coil sensor fault
What our technician checks
- Outdoor sensor (ambient / coil / suction): unplug and measure against the brand chart (outdoor ones are usually 10 kΩ, discharge sensors 50-200 kΩ at 25°C).
F22
Outdoor AC over-current
What our technician checks
- Supply voltage under load, condenser dirty or outdoor fan slow, overcharge, air in system, compressor current against rated.
F23
Compressor U/V/W phase over-current
What our technician checks
- Power off, wait for capacitors to discharge. Compressor U-V, V-W, W-U equal (about 0.5-3 Ω) and >10 MΩ to earth. Diode test the IPM P/N to U/V/W. Check DC bus (about 310 V DC on 230 V supply), heat-sink paste and screws, condenser cleanliness, supply voltage, overcharge.
F24
CT current detection abnormal
What our technician checks
- Current sensing circuit on the outdoor board.
F25
Discharge sensor abnormal
What our technician checks
- Discharge pipe sensor: measure (typically 50-200 kΩ at 25°C, brand dependent) and check it is fixed on the discharge pipe.
F27
Compressor current sampling circuit fault
What our technician checks
- Current sensing circuit on the outdoor board.
F28
Compressor position detection circuit fault
What our technician checks
- Compressor leads and windings
- board drive section.
F35
Compressor driver board failure
What our technician checks
- Power off, wait for capacitors to discharge. Compressor U-V, V-W, W-U equal (about 0.5-3 Ω) and >10 MΩ to earth. Diode test the IPM P/N to U/V/W. Check DC bus (about 310 V DC on 230 V supply), heat-sink paste and screws, condenser cleanliness, supply voltage, overcharge.
F43
Model matching abnormality
What our technician checks
- Indoor and outdoor model numbers are a matching pair? Correct capacity / model setting on the board.
FE
Refrigerant leak detected (fixed speed)
What our technician checks
- Suction pressure low? Leak test (flare joints, valves, coils) with soap / nitrogen. Valves fully open?
Code not here, or still showing?
Send a photo of the display and the model sticker on WhatsApp. We'll tell you what it means and whether it needs a visit.
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